The application of 3D-bioprinted scaffolds for neuronal regeneration after traumatic spinal cord injury - A systematic review of preclinical in vivo studies.

BACKGROUND

The implantation of 3D-bioprinted scaffolds represents a promising therapeutic approach for traumatic Spinal Cord Injury (SCI), currently investigating in preclinical in vivo studies. However, a systematic review of the relevant literature has not been performed to date. Hence, we systematically reviewed the outcomes of the application of 3D-bioprinted implants in the treatment of SCI based on studies conducted on experimental animal models.

METHODS

We searched PubMed, Scopus, Web of Science, and Cochrane Library databases. Manuscripts in other designs than in vivo preclinical study and written in other languages than English were excluded. A risk of bias assessment was performed using SYRCLE's tool. The quality of included articles was assessed by ARRIVE guidelines. Extracted data were synthesized only qualitatively because the data were not suitable for conducting the meta-analysis.

RESULTS

Overall, eleven animal studies reporting on the transection SCI rat model were included. Six of included studies investigated 3D-bioprinted scaffolds enriched with stem cells, two studies - 3D-bioprinted scaffolds combined with growth factors, and three studies - stand-alone 3D-bioprinted scaffolds. In all included studies the application of 3D-bioprinted scaffolds led to significant improvement in functional scores compared with no treated SCI rats. The functional recovery corresponded with the changes observed at the injury site in histological analyses. Seven studies demonstrated medium, three studies - high, and one study - low risk of bias. Moreover, some of the included studies were conducted in the same scientific center. The overall quality assessment ratio amounted to 0.60, which was considered average quality.

CONCLUSION

The results of our systematic review suggest that 3D-bioprinted scaffolds may be a feasible therapeutic approach for the treatment of SCI. Further evidence obtained on other experimental SCI models is necessary before the clinical translation of 3D-bioprinted scaffolds.