Growth Factor Gene-Modified Cells in Spinal Cord Injury Recovery: A Systematic Review

• Published in: World neurosurgery 2022-06, Vol.162, p.150-162.e1
• Main Authors: Yousefifard, Mahmoud, Sarveazad, Arash, Babahajian, Asrin, Rafiei Alavi, Seyedeh Niloufar, Madani Neishaboori, Arian, Vaccaro, Alex R., Hosseini, Mostafa, Rahimi-Movaghar, Vafa
• Format: Article
• Language: English
• Subjects: Animal; Growth factor; Locomotion; Spinal cord injuries
• ISSN: 1878-8750; 1878-8769
• DOI: 10.1016/j.wneu.2022.03.012

Numerous preclinical studies have been performed in recent years on the effects of the administration of growth factor gene-modified cells in spinal cord injury (SCI). However, findings of these studies are contradictory. The present study aims to conduct a systematic review and meta-analysis of animal studies evaluating the effects of administration of growth factor gene-modified cells on locomotion recovery after SCI. A search of the MEDLINE, Embase, Scopus, and Web of Science databases was conducted, including all animal studies until the end of 2020. Two researchers screened search results, summarized relevant studies and assessed risk of bias, independently. Thirty-three studies were included in the final analysis. Transplantation of growth factor gene-modified cells in the injured spinal cord resulted in a significant improvement in locomotion of animals compared with nontreated animals (standardized mean difference = 1.86; 95% confidence interval, 1.39–2.33; P < 0.0001)] and non-genetically modified cell–treated animals (standardized mean difference = 1.30; 95% confidence interval, 0.80–1.79; P < 0.0001). Transplantation efficacy of these cells failed to achieve significance in moderate lesions (P = 0.091), when using modified neural stem/progenitor cells (P = 0.164), when using synthetic neurotrophins (P = 0.086) and when the number of transplanted cells was less than 1.0 × 105 cells per animal (P = 0.119). The results showed that transplantation of growth factor gene– modified cells significantly improved locomotion in SCI animal models. However, there is a major concern regarding the safety of transplantation of genetically modified cells, in terms of overexpressing growth factors. Further studies are needed before any effort to perform a translational and clinical study.