AO Spine Reference Centre & Institute of Health & Biomedical Innovation, Queensland University of Technology, Brisbane, Australia

Traumatic spinal cord injury (SCI) is a devastating condition with no curative therapy. Pro-inflammatory therapy has been suggested recently to try and reduce the inhibitory glial scar and promote neural regeneration and healing. The aim of this study is to investigate the potential of sustained delivery of angiogenic/pro-inflammatory growth factors to reduce the secondary degeneration after spinal cord injury.

Adult male Wistar Kyoto rats (200-300g; 12-16weeks old) were subjected to cord hemisections via a T10 laminectomy. Animals were randomised to treatment or control groups after the spinal cord injury had been induced. Treatment consisted of implantation of a mini-osmotic pump capable of delivering 5 micrograms vascular endothelial growth factor (VEGF) and 5 micrograms platelet-derived growth factor (PDGF), via a catheter, to the site of the lesion, over 7 days(n=6). Control animals were subjected to either cord lesion only (n=6) or lesion plus mini-pump delivering PBS (phosphate-buffered saline) solution (n=6). Rats were sacrificed at one month and the spinal cords were harvested and examined by immunohistology, using anti-neurofilament-200 and anti-Glial Acidic Fibrillary Acidic Protein (GFAP) antibodies.

RESULTS: Active treatment spinal cords showed a higher level with aboration of the axonal filament through the defect and more dense neurofilament-200 staining at the lesion site compared to both control groups. The treatment also showed the elevated presence of activated microglia in the lesion, whilst distal to the lesion the microglia and astrocytes retained an unreactive phenotype.

Pro-inflammatory therapy in the rat spinal cord-injury model showed favourable histological findings after sustained delivery of PDGF and VEGF

Introduction Fluid dynamics in the intervertebral disc plays an important role in the overall mechanical function as well as nutritional supply for both the annulus fibrosis (AF) and the nucleus pulposus (NP). The apparent diffusion coefficient of water in intervertebral discs has been suggested to be related to the matrix composition as well as the structural integrity of the disc.

Methods Lesions were created in two intervertebral lumbar discs in 18 in-bred Sprague Dawley rats (approved by Animal Ethics Committee) using a 14G hypodermic syringe to induce degenerative change as described by Sobajima et al (1). Regenerative treatment involved the injection of multipotent stem cells isolated from the olfactory mucosa. These cells were injected either at the time of creation of the lesion or six weeks after creation of the lesion.

MRI experiments were undertaken at 25.0 ± 0.1 °C on a Bruker Avance NMR spectrometer (Bruker Bio-Spin, Rheinstetten, Germany) using a 7.0T vertical bore magnet system, equipped with a 1.1 T m-1 (110 G cm-1) gradient set and 15 mm ‘birdcage’ RF resonator. Specimens for testing were immersed in physiological saline inside a 15 mm NMR. Both multi echo and diffusion weighted images were acquired with a recycle time TR = 2 s and 8 averages using a 0.7 mm slice thickness, a field of view (FOV) of ca. 15 × 15 mm and a 128 × 128 matrix. For multi echo experiments the echo time was 5 ms with 64 echoes and for DT imaging a diffusion gradient duration δ = 2 ms and diffusion delay Δ = 12 ms. The diffusion tensor was calculated from the seven requisite diffusion-weighted images using in-house Matlab® code (The Mathworks, Natick, MA) written for the purpose.

Results Preliminary results of the multi echo images indicate that intervertebral disc degradation results in observable differences in the T2 of the NP ((mean/SD (ms)) control disc (63.2/3.4), untreated (49.5/1.4) and treated (49.7/3.4)). Diffusion tensor results show isotropic diffusion in the NP with anisotropic diffusion in the AF and observable differences in magnitude.

Discussion The use of high resolution MRI has been shown to provide a useful tool for quantifying the effects of regenerative treatments for degenerative disc disease.

Introduction The devastating and permanent effects of complete spinal cord injury are well documented. In animal models, olfactory ensheathing cells (OEC) transplanted into areas of complete spinal cord injury have promoted regeneration of the neural elements with reconnection of the descending motor pathways. This reproducible anatomical finding is associated with significant motor functional recovery. Accordingly, cellular transplantation therapies have been advocated for human spinal cord injury.

In a single-blind, Phase I clinical trial, we aimed to test the feasibility and safety of transplantation of autologous olfactory ensheathing cells into the spinal cord of three humans with complete spinal cord injury. This paper describes the trial and the surgical procedures and presents twelve month safety data.

Methods Six patients with paraplegia resulting from chronic (6 – 36 months post-injury) traumatic spinal cord injury (thoracic) were enrolled in the trial. Exclusion criteria included the presence of vertebral column instability, syringomyelia, an implanted spinal device or instrumentation and the presence of psychological instability. The patients were allocated to a treatment group and a control group. No intervention was undertaken to the control group.

Olfactory ensheathing cells were harvested from each subject in the surgery group, grown and purified in vitro. After exposure via laminectomy, durotomy and adhesolysis, the cells were injected into the region of injured spinal cord.

All patients are tested on enrollment and then at regular intervals up to three years by a group of assessors who are blinded to the treatment or control group status. These assessments include physical, radiological, neurophysiological and psychosocial parameters.

Results All surgery patients exhibited continuity of presumed pia through the cystic region at the site of injury. The spinal cord adjacent to the cyst appeared macroscopically normal. There were no complications of surgery evident in the peri-operative period. At twelve months there was no evidence of tumour formation, syrinx development, clinical or psychosocial deterioration.

Discussion The dictum, primum non nocere, is especially relevant to the emerging field of human spinal cord regeneration. Animal models promise such exciting potentials for therapy in this devastating condition, that the possibilities need to be fully explored. Anecdotal, non-trial based reports suggest that equivalent results may be able to be obtained in humans. However, science and care should guide the endeavours in this controversial field.

This is the first reported trial of OEC’s in human spinal cord injury. Twelve-month data in a small cohort shows that there is no evidence of adverse events that would preclude completion of the current trial and the development of efficacy trials.