Cervical spinal cord therapeutics delivery: Preclinical safety validation of a stabilized microinjection platform

Jonathan Riley, Thais Federici, John Park, Masatoshi Suzuki, Colin K. Franz, Craig Tork, Jacalyn McHugh, Qingshan Teng, Clive Svendsen, Nicholas M. Boulis

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

OBJECTIVE: The current series represents a preclinical safety validation study for direct parenchymal microinjection of cellular grafts into the ventral horn of the porcine cervical spinal cord. METHODS: Twenty-four 30- to 40-kg female Yorkshire farm pigs immunosuppressed with cyclosporine underwent a cervical laminectomy and ventral horn human neural progenitor cell injection. Cell transplantation in groups 1 to 3 (n = 6 pigs each) was undertaken with the intent of assessing the safety of varied injection volumes: 10, 25, and 50 μL injected at 1, 2.5, and 5 μL/min, respectively. Groups 4 and 5 (n = 3 pigs each) received prolonged immunosuppressant pretreatment in an attempt to demonstrate graft viability. The latter was undertaken in an alternate species (mini-pig versus Yorkshire pig). RESULTS: Neurological morbidity was observed in 1 animal and was attributable to the presence of a resolving epidural hematoma noted at necropsy. Although instances of ventral horn targeting were achieved in all injection groups with a coordinate-based approach, opportunities exist for improvement in accuracy and precision. A relationship between injection volume and graft site cross-sectional area suggested limited reflux. Only animals from group 5 achieved graft survival at a survival end point (t = 1 week). CONCLUSION: This series demonstrated the functional safety of targeted ventral horn microinjection despite evidence for graft site immune rejection. Improvements in graft delivery may be augmented with an adapter to improve control of the cannula entry angle, intraoperative imaging, or larger graft volumes. Finally, demonstration of long-term graft viability in future preclinical toxicity studies may require tailored immunosuppressive therapies, an allograft construct, or tailored choice of host species.

Original languageEnglish (US)
Pages (from-to)754-761
Number of pages8
JournalNeurosurgery
Volume65
Issue number4
DOIs
StatePublished - Oct 2009

Keywords

  • Cell therapy
  • Cervical spinal cord
  • Microinjection
  • Neural progenitor cells
  • Pigs

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology

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