Efficacy of hydrogels for repair of traumatic spinal cord injuries: A systematic review and meta‐analysis

Abstract

Hydrogels have been used as promising biomaterials for regeneration and control of pathophysiological events after traumatic spinal cord injuries (TSCI). However, no systematic comparison was conducted to show the effect of hydrogels on pathophysiological events. This study was designed to address this issue and evaluate the regenerative potential of hydrogels after TSCI. From 2857 records found in MEDLINE and EMBASE databases (April 23, 2021), 49 articles were included based on our inclusion/exclusion criteria. All studies discussing the effect of hydrogels on at least one of the main pathophysiological events after TSCI, including inflammation, axon growth, remyelination, glial scar formation, cavity size, and locomotor functional recovery were included. For statistical analysis, we used mean difference with 95% confidence intervals for locomotor functional recovery. The results showed that both natural and synthetic hydrogels could reduce the inflammatory response, hinder glial scar formation, and promote axon growth and vascularization. Also, the meta‐analysis of the BBB score showed that using the hydrogels can lead to locomotor functional recovery. It was found that hydrogels are more efficient when used in transection and hemisection injuries (SMD: 1.89; 95% CI: 1.26, 2.52; P < .00001) compared to other injury models. The pre‐formed implanted hydrogels (SMD: 1.79; 95% CI: 1.24, 2.34; P < .00001) found to be more effective compared to injection (SMD: 1.58; 95% CI: 0.64, 2.52; P = 0.0009). In conclusion, based on the available evidence, it was concluded that hydrogel composition as well as implantation method are dominant factors affecting tissue regeneration after TSCI and should be chosen according to the injury model in animal studies.

Astrogliosis: A review of the astrocytic mechanisms, imaging modes, and treatments in spinal cord injury patients

“…Several novel treatments have shown promise in ameliorating SCI sequelae. One of these is hydrogels, an analog of the extracellular matrix of a soft tissue [59].…”

“…In their systematic review and meta-analysis of animal models, Ayar et al [59] found notable improvements in the pathophysiological outcomes of SCI after treatment with hydrogels. One such finding includes the potential of hydrogels to improve motor function after SC.…”

“…One such finding includes the potential of hydrogels to improve motor function after SC. The authors conducted a meta-analysis of Basso, Beattie, and Bresnahan scores and found that there were statistically significant improvements in functional capacity after either injection or implantation of hydrogels [59]. Of note, there was high heterogeneity among the studies which was addressed through subsequent subgroup analysis [59].…”

“…The authors conducted a meta-analysis of Basso, Beattie, and Bresnahan scores and found that there were statistically significant improvements in functional capacity after either injection or implantation of hydrogels [59]. Of note, there was high heterogeneity among the studies which was addressed through subsequent subgroup analysis [59]. The etiology of the SCI was strongly indicative of motor function recovery [59].…”

Cooperative assembly of a designer peptide and silk fibroin into hybrid nanofiber gels for neural regeneration after spinal cord injury

“…A widely used strategy is to locally reconstruct a permissive environment for neural regeneration with biomaterials, which can provide physical and biochemical cues to axonal growth. As a three-dimensional (3D) aqueous matrix, hydrogel has been regarded as an appealing option that can simulate the complex structure of ECM and serve as a bridge to promote neural regeneration ( 3 ).…”