Delivery of chondroitinase by canine mucosal olfactory ensheathing cells alongside rehabilitation enhances recovery after spinal cord injury.

Spinal cord injury (SCI) can cause chronic paralysis and incontinence and remains a major worldwide healthcare burden, with no regenerative treatment clinically available. Intraspinal transplantation of olfactory ensheathing cells (OECs) and injection of chondroitinase ABC (chABC) are both promising therapies but limited and unpredictable responses are seen, particularly in canine clinical trials. Sustained delivery of chABC presents a challenge due to its thermal instability; we hypothesised that transplantation of canine olfactory mucosal OECs genetically modified ex vivo by lentiviral transduction to express chABC (cOEC-chABC) would provide novel delivery of chABC and synergistic therapy. Rats were randomly divided into cOEC-chABC, cOEC, or vehicle transplanted groups and received transplant immediately after dorsal column crush corticospinal tract (CST) injury. Rehabilitation for forepaw reaching and blinded behavioural testing was conducted for 8 weeks. We show that cOEC-chABC transplanted animals recover greater forepaw reaching accuracy on Whishaw testing and more normal gait than cOEC transplanted or vehicle control rats. Increased CST axon sprouting cranial to the injury and serotonergic fibres caudal to the injury suggest a mechanism for recovery. We therefore demonstrate that cOECs can deliver sufficient chABC to drive modest functional improvement, and that this genetically engineered cellular and molecular approach is a feasible combination therapy for SCI.

Three-Dimensional-Printed Patient-Specific Osteotomy Guides, Repositioning Guides and Titanium Plates for Acute Correction of Antebrachial Limb Deformities in Dogs.

OBJECTIVE: The aim of this study was to describe the use of patient-specific three-dimensional (3D)-printed osteotomy guides, repositioning guides and custom-printed titanium plates for acute correction of antebrachial limb deformities in four dogs. METHODS: Retrospective review of antebrachial limb deformities in small breed chondrodystrophic dogs that were surgically corrected using a closing wedge ostectomy of the radius at a predetermined site using patient-specific osteotomy guides. Reduction was achieved without the need for intraoperative measurements using patient-specific 3D-printed repositioning guides secured and manipulated using temporary Kirschner wire fixation. The ostectomy of the radius was stabilized with a patient-specific 3D-printed titanium plate. RESULTS: All limbs were corrected to within 3.5 degrees (standard deviation [SD]: 1 degree) and 7.5 degrees (SD: 3 degrees) of the pre-planned deformity correction in the frontal and sagittal planes, respectively. No complications were encountered. Owners completed a canine orthopaedic index survey at a median postoperative follow-up time of 19 months. Surgery eliminated the main presenting complaint of buckling over of the manus in all cases. CLINICAL SIGNIFICANCE: The 3D-printed osteotomy repositioning guides and titanium plates facilitated accurate acute correction of antebrachial deformities in this case series. The methodology described simplifies intraoperative surgical decision-making on limb position with good clinical outcomes seen in a small number of clinical cases.

Nanoparticle-Based Imaging of Clinical Transplant Populations Encapsulated in Protective Polymer Matrices.

A recent clinical trial proves that autologous olfactory mucosal cell (OMC) transplantation improves locomotion in dogs with naturally occurring spinal injuries comparable to human lesions. However, not all dogs respond to the treatment, likely due to the transplantation procedures involving injections of cell suspensions that are associated with cell death, uneven cell distribution, and cell washout. Encapsulating cells in protective hydrogel matrices offers a tissue engineering solution to safely achieve 3D growth of viable transplant cells for implantation into injury sites, to improve regenerative outcomes. It is shown for the first time that canine OMCs (cOMCs) can be propagated with high viability in 3D collagen matrices. Further, a method to incorporate cOMCs pre-labeled with clinical-grade iron oxide nanoparticles into the constructs is described. Intraconstruct labeled cells are visualized using magnetic resonance imaging, offering substantial promise for in vivo tracking of cOMCs delivered in protective matrices.

A fusion of minicircle DNA and nanoparticle delivery technologies facilitates therapeutic genetic engineering of autologous canine olfactory mucosal cells.

Olfactory ensheathing cells (OECs) promote axonal regeneration and improve locomotor function when transplanted into the injured spinal cord. A recent clinical trial demonstrated improved motor function in domestic dogs with spinal injury following autologous OEC transplantation. Their utility in canines offers promise for human translation, as dogs are comparable to humans in terms of clinical management and genetic/environmental variation. Moreover, the autologous, minimally invasive derivation of OECs makes them viable for human spinal injury investigation. Genetic engineering of transplant populations may augment their therapeutic potential, but relies heavily on viral methods which have several drawbacks for clinical translation. We present here the first proof that magnetic particles deployed with applied magnetic fields and advanced DNA minicircle vectors can safely bioengineer OECs to secrete a key neurotrophic factor, with an efficiency approaching that of viral vectors. We suggest that our alternative approach offers high translational potential for the delivery of augmented clinical cell therapies.

Effectiveness of manual bladder expression in paraplegic dogs.

OBJECTIVE To determine the effectiveness of manual bladder expression in paraplegic dogs by comparing urine volumes measured by use of intermittent catheterization and ultrasonography. ANIMALS 36 paraplegic dogs. PROCEDURES 93 measurements of bladder volume were collected for the 36 dogs. Residual urine volume was determined by use of intermittent urethral catheterization and estimated by use of ultrasonography. RESULTS Manual bladder expression voided a mean of 49% of urine from the bladder in this population of dogs. There was no correlation (R2, 0.06) between the effectiveness of manual bladder expression and body weight. Ultrasonographic estimation of bladder volume had good correlation (R2, 0.62) with bladder volume determined by use of intermittent bladder catheterization, but clinically unacceptable variation for predicting actual bladder volume (mean difference, 22 mL; 95% confidence interval, -96 to 139 mL). CONCLUSIONS AND CLINICAL RELEVANCE Manual bladder expression was ineffective at completely emptying urine from the bladder of paraplegic dogs, but the effectiveness of the procedure was not affected by body weight. Manual bladder expression would likely be a useful procedure to prevent increases in pressure within the bladder. Ultrasonographic estimation of bladder volume could be a useful predictor of actual bladder volume, but it was susceptible to wide variations among dogs, and results should therefore be interpreted with caution.