Acidic Fibroblast Growth Factor in Spinal Cord Injury

Abstract

Spinal cord injury (SCI), with an incidence rate of 246 per million person-years among adults in Taiwan, remains a devastating disease in the modern day. Elderly men with lower socioeconomic status have an even higher risk for SCI. Despite advances made in medicine and technology to date, there are few effective treatments for SCI due to limitations in the regenerative capacity of the adult central nervous system. Experiments and clinical trials have explored neuro-regeneration in human SCI, encompassing cell- and molecule-based therapies. Furthermore, strategies have aimed at restoring connections, including autologous peripheral nerve grafts and biomaterial scaffolds that theoretically promote axonal growth. Most molecule-based therapies target the modulation of inhibitory molecules to promote axonal growth, degrade glial scarring obstacles, and stimulate intrinsic regenerative capacity. Among them, acidic fibroblast growth factor (aFGF) has been investigated for nerve repair; it is mitogenic and pluripotent in nature and could enhance axonal growth and mitigate glial scarring. For more than 2 decades, the authors have conducted multiple trials, including human and animal experiments, using aFGF to repair nerve injuries, including central and peripheral nerves. In these trials, aFGF has shown promise for neural regeneration, and in the future, more trials and applications should investigate aFGF as a neurotrophic factor. Focusing on aFGF, the current review aimed to summarize the historical evolution of the utilization of aFGF in SCI and nerve injuries, to present applications and trials, to summarize briefly its possible mechanisms, and to provide future perspectives.

Keywords: Acidic fibroblast growth factor; Regeneration; Spinal cord injury.

Fig. 1.

Brief pathophysiology of SCI. The sequential damage of SCI is a combination of the primary trauma and secondary injury. The primary mechanical injury directly injures the axons and breaks down the blood-spinal cord barrier (BScB) within the initial hours. In the following days, secondary injury flare-up occurs with the infiltration of the immune cells (macrophages, neutrophils, and microglia) into the injured site. Also, within days to weeks, the astrocytes are activated and form a glial scar to envelop the injured area and to limit the range of the inflammatory response. In the following weeks to months, the glial scar reconstructs a firm shell surrounding the injured area, and eventually forms a cyst or cavity consisting of necrotic cells inside.