Brain-derived neurotrophic factor (BDNF) as biomarker in stem cell-based therapies of preclinical spinal cord injury models: A systematic review.

Stem cell-based therapies offer promising treatment for spinal cord injury (SCI) by reducing inflammation, restoring plasticity, and supporting neuroprotection and nerve regeneration. Brain-derived neurotrophic factor (BDNF) is crucial in SCI pathophysiology. This study reviews the impact of stem cells on BDNF expression in preclinical SCI models. A thorough search was performed in PubMed, Scopus, and Web of Science until June 2023, identifying studies on the effects of stem cells on BDNF in SCI. Two researchers reviewed and extracted data from relevant studies. This review is registered in the Prospective Register of Systematic Reviews (PROSPERO) with the registration number [CRD42023441466]. Out of 923 records, 51 studies met the inclusion criteria, involving rats (46 studies) and mice (5 studies). The contusion or compression model was used in 40 studies, and the transection model in 11. The most common stem cell types were bone marrow mesenchymal stem cells (BM-MSCs), neural stem cells (NSCs), and adipose-derived stem cells (ADSCs). BM-MSCs increased BDNF expression in 16 studies, NSCs in 9 studies, and ADSCs in only one study. This review highlights that BM-MSCs and NSCs are effective in enhancing BDNF expression in preclinical SCI models, while other stem cell types may not significantly affect BDNF levels. These findings suggest variability in the effectiveness of different stem cell therapies in modulating BDNF production for SCI treatment.