Homing of mesenchymal stem cells after acute traumatic cervical spinal cord injury – a case report

Background & Aim Mesenchimal stem cell (MSC) therapy has been studied for years as a possible treatment strategy for traumatic spinal cord injury (tSCI), which usually results in severe permanent neurologic deficits. Here we report a case on the migration and homing ability of MSC transplanted by the intravenous and intrathecal route after tSCI. Methods, Results & Conclusion METHODS: A 33-year old male patient with complete tSCI after cervical spine dislocation at theC3 - C4 spinal level due to a diving accident underwent immediate surgical 360° decompression and instrumented fusion. Postoperative MRI showed severe spinal cord injury with minimal residual spinal cord tissue (Figure 1). Three months after injury autologous MSC were harvested from the patient`s iliac crest bone marrow and cultivated. The dose of 150 million MSC were transplanted via the intravenous route, of these one third were radiolabeled with 600MBq of 99mTc-exametazime (HMPAO). Whole-body planar and hybrid (SPECT/CT) imaging of the head and neck, to follow cell migration, were performed at 1h, 4h and 20h after transplantation. After two weeks another 150 million MSC of the same culture were transplanted directly intrathecally per lumbar puncture using the same labeling and imaging protocol and the results of the imaging between intravenous and intratechal administration were compared. RESULTS After intravenous administration, MSC were distributed in the reticuloendothelial system and in the lung parenchyma, as seen on hybrid SPECT/CT imaging and MSC retention at the site of spinal cord injury was unremarkable at any time frame. (Figure 2) After intrathecal administration, accumulation of radiolabeled MSC at the level of administration (L 3) with slow rostral progression was demonstrated on whole-body planar SPECT/CT imaging. On hybrid SPECT/CT imaging intense retention of MSC was observed at the site of spinal cord injury one hour after injection with slow gradual increase in the signal at 4h after administration. A widespread signal throughout the whole spinal canal was observed at 20h after administration due to intense background activity. (Figure 3) CONCLUSION These results suggest the existence of a homing signal that facilitates migration and engraftment of MSC at the site of spinal cord injury three months after acute tSCI and suggest that intrathecal administration is more effective than intravenous administration as the route for MSC transplantation in this respect.