Effect of canine mesenchymal stromal cells overexpressing heme oxygenase-1 in spinal cord injury.

Heme oxygenase-1 (HO-1) is a stress-responsive enzyme that modulates the immune response and oxidative stress associated with spinal cord injury (SCI). This study aimed to investigate neuronal regeneration via transplantation of mesenchymal stromal cells (MSCs) overexpressing HO-1. Canine MSCs overexpressing HO-1 were generated by using a lentivirus packaging protocol. Eight beagle dogs with experimentally-induced SCI were divided into GFP-labeled MSC (MSC-GFP) and HO-1-overexpressing MSC (MSC-HO-1) groups. MSCs (1 × 107 cells) were transplanted at 1 week after SCI. Spinal cords were harvested 8 weeks after transplantation, after which histopathological, immunofluorescence, and western blot analyses were performed. The MSC-HO-1 group showed significantly improved functional recovery at 7 weeks after transplantation. Histopathological results showed fibrotic changes and microglial cell infiltration were significantly decreased in the MSC-HO-1 group. Immunohistochemical (IHC) results showed significantly increased expression levels of HO-1 and neuronal markers in the MSC-HO-1 group. Western blot results showed significantly decreased expression of tumor necrosis factor-alpha, interleukin-6, cycloogygenase 2, phosphorylated-signal transducer and activator of transcription 3, and galactosylceramidase in the MSC-HO-1 group, while expression levels of glial fibrillary acidic protein, ß3-tubulin, neurofilament medium, and neuronal nuclear antigen were similar to those observed in IHC results. Our results demonstrate that functional recovery after SCI can be promoted to a greater extent by transplantation of HO-1-overexpressing MSCs than by normal MSCs.

Impact of local injection of brain-derived neurotrophic factor-expressing mesenchymal stromal cells (MSCs) combined with intravenous MSC delivery in a canine model of chronic spinal cord injury.

BACKGROUND AIMS: The microenvironment of the chronically injured spinal cord does not allow for axonal regeneration due to glial scarring. To ameliorate this, several therapeutic strategies have been used. We investigated whether combined transplantation of chondroitinase ABC (chABC) and mesenchymal stromal cells (MSCs) genetically modified to secrete brain-derived neurotrophic factor (BDNF) with intravenous (IV) administration of MSCs can promote recovery of hindlimb function after chronic spinal cord injury (SCI). METHODS: Canine BDNF-expressing MSCs were generated using a lentivirus packaging protocol. Twelve beagle dogs with experimentally induced chronic SCI were divided into chABC/MSC-green fluorescent protein (GFP), chABC/MSC-BDNF and chABC/MSC-BDNF/IV groups. The MSCs (1 × 107 cells) and chABC were transplanted 3 weeks after SCI in all groups, and IV injection of MSC-GFP (1 × 107 cells) was performed 1 and 2 weeks after MSC transplantation in the chABC/MSC-BDNF/IV group. Spinal cords were harvested 8 weeks after transplantation. RESULTS: The dogs in the chABC/MSC-BDNF included groups had significantly improved functional recovery 8 weeks after transplantation compared with those in the chABC/MSC-GFP group. The animals in the chABC/MSC-BDNF/IV group showed significant improvements in functional recovery at 6, 7 and 8 weeks compared with those in the chABC/MSC-BDNF group. Fibrotic changes were significantly decreased in the chABC/MSC-BDNF/IV group. We also observed significant decreases in the expression levels of tumor necrosis factor-α, interleukin-6, COX-2, glial fibrillary acidic protein and GalC and increased expression levels of BDNF, ß3-tubulin neurofilament medium, and nestin in the chABC/MSC-BDNF/IV group. CONCLUSIONS: We suggest that transplantation of combined chABC and BDNF-expressing MSCs, along with IV injection of MSCs, is the optimal therapy for chronic SCI.

Effect of the combination of mesenchymal stromal cells and chondroitinase ABC on chronic spinal cord injury.

Transplantation of mesenchymal stromal cells (MSCs) has been identified as a potential therapeutic modality for treating spinal cord injury (SCI). Degradation of chondroitin sulfate proteoglycans (CSPGs) using the enzyme chondroitinase ABC (chABC) can promote functional recovery after SCI. The effect of the simultaneous administration of MSCs and chABC on chronic SCI was investigated. Sixteen dogs were assigned to one of the following four groups: (i) canine adipose tissue-derived MSCs (cADMSCs), (ii) chABC, (iii) cADMSCs + chABC and (iv) control. Treatments were carried out 3 weeks after SCI; cADMSCs (1 × 10(7) cells suspended in 150 µL of PBS), chABC (5 U/mL, 150 µL), cADMSCs + chABC (1 × 10(7) cells suspended in 150 µL of chABC), or phosphate-buffered saline (150 µL) were injected into the spinal cord at three locations to a depth of 3 mm using a 30-gauge needle. The spinal cord was harvested 8 weeks after transplantation. In a behavioral assessment, dogs treated with cADMSCs + chABC and cADMSCs alone showed significantly better functional recovery 8 weeks after transplantation compared with the control and chABC groups (P < 0.05). In addition, the combination of cADMSCs and chABC increased the expression of digested CSPGs (2B6), ß3 tubulin, and NF-M. However, the levels of COX2 (P < 0.05), and tumor necrosis factor-α was higher in the treatment groups than in the control. In conclusion, transplantation of cADMSCs + chABC was more effective in improving clinical signs and neural regeneration, but a strategy for anti-inflammation after the treatment for chronic SCI would be needed for further improvement.

Effect of serum-derived albumin scaffold and canine adipose tissue-derived mesenchymal stem cells on osteogenesis in canine segmental bone defect model.

Composite biological and synthetic grafts with progenitor cells offer an alternative approach to auto- or allografts for fracture repair. This study was conducted to evaluate osteogenesis of autologous serum-derived albumin (ASA) scaffolds seeded with canine adipose tissue-derived mesenchymal stem cells (Ad-MSCs) in a canine segmental bone defect model. ASA scaffold was prepared with canine serum using cross-linking and freeze-drying procedures. Beta-tricalcium phosphate (ß-TCP) was mixed at the cross-linking stage. Ad-MSCs were seeded into the scaffold and incubated for one day before implantation. After 16 weeks, the grafts were harvested for histological analysis. The dogs were divided into five groups: control, ASA scaffolds with and without Ad-MSCs, and ASA scaffolds including ß-TCP with and without Ad-MSCs. ASA scaffolds with Ad-MSCs had a significantly larger area of increased opacity at the proximal and distal host cortex-implant interfaces in radiographs 16 weeks after implantation compared to the groups with ß-TCP (p < 0.05). Histomorphometric analysis showed that ASA scaffolds with Ad-MSCs had significantly greater new bone formation than other groups (p < 0.05). These results suggest that Ad-MSCs seeded into ASA scaffolds enhanced osteogenesis in the bone defect model, but that ß-TCP in the ASA scaffold might prevent penetration of the cells required for bone healing.