Sung-Su Park

Functional recovery after spinal cord injury in dogs treated with a combination of Matrigel and neural-induced adipose-derived mesenchymal Stem cells.

BACKGROUND AIMS Previous studies have reported that scaffold or cell-based transplantation may improve functional recovery following spinal cord injury (SCI), but these results were based on neuronal regeneration and cell replacement. In this study, we investigated whether a combination of Matrigel and neural-induced mesenchymal stem cells (NMSC) improved hindlimb function in dogs with SCI, and what mechanisms were involved. METHODS We pre-differentiated canine adipose-derived mesenchymal stem cells into NMSC. A total of 12 dogs subjected to SCI procedures were assigned to one of the following three transplantation treatment groups: phosphate-buffered saline (PBS); Matrigel; or Matrigel seeded with NMSC. Treatment occurred 1 week after SCI. Basso, Beattie and Bresnahan (B.B.B.) and Tarlov scores, histopathology, immunofluorescence staining and Western blot analysis were used to evaluate the treatment effects. RESULTS Compared with dogs administered PBS or Matrigel alone, dogs treated with Matrigel + NMSC showed significantly better functional recovery 8 weeks after transplantation. Histology and immunochemical analysis revealed that the combination of Matrigel + NMSC reduced fibrosis from secondary injury processes and improved neuronal regeneration more than the other treatments. In addition, the combination of Matrigel + NMSC decreased the expression of inflammation and/or astrogliosis markers. Increased expressions of intracellular molecules related to neuronal extension, neuronal markers and neurotrophic factors were also found in the Matrigel + NMSC group. However, the expression of nestin as a neural stem cell marker was increased with Matrigel alone. CONCLUSIONS The combination of Matrigel + NMSC produced beneficial effects in dogs with regard to functional recovery following SCI through enhancement of anti-inflammation, anti-astrogliosis, neuronal extension and neuronal regeneration effects.

Comparison of canine umbilical cord blood-derived mesenchymal stem cell transplantation times: involvement of astrogliosis, inflammation, intracellular actin cytoskeleton pathways, and neurotrophin-3.

Canine mesenchymal stem cells (cMSCs) derived from umbilical cord blood represent a potentially useful source of stem cells for therapy. The aim of this study was to compare the effects of different transplantation times of cMSCs after spinal cord injury (SCI). A total of 21 dogs were subjected to SCI by balloon-induced compression of the first lumbar vertebrae for 12 h. Of the 21 dogs, 12 were divided into four groups of three according to the time of stem cell (1 × 106) transplantation at the injury site: control no treatment, 12 h, 1 week, and 2 weeks. The remaining 9 animals were negative harvest (HA) time controls for each treatment group (n = 3). Olby and Tarlov scores were used to evaluate functional recovery of the hindlimbs. Markers for neuronal regeneration (Tuj-1, nestin, MAP2, and NF-M), astrogliosis (GALC, GFAP, and pSTAT3), signal molecules for actin cytoskeleton (RhoA, Cdc42, and Rac1), inflammation (COX-2), and neurotrophins (NT-3) were evaluated by Western blot analysis. Scores of the 1-week transplantation group showed significant improvement compared to controls. Hematoxylin and eosin (H&E) staining revealed less fibrosis at the injury site in the 1-week transplantation group compared to other groups and immunohistochemistry showed increased expression of neuronal markers. Furthermore, in both 1-week and 2-week transplantation groups, Tuj-1, nestin, MAP2, NF-M, NT-3, and GFAP increased, but pSTAT3, GALC, and COX2 decreased. RhoA decreased and Rac1 and Cdc42 increased in the 1-week transplantation group. In conclusion, transplantation of cMSCs 1 week after SCI was more effective in improving clinical signs and neuronal regeneration and reducing fibrosis formation compared to the other transplantation times evaluated. Subsequently, these data may contribute to the optimization of timing for MSC transplantation used as a therapeutic modality.

Role of laminin-111 in neurotrophin-3 production of canine adipose-derived stem cells: involvement of Akt, mTOR, and p70S6K.

Extracellular matrix (ECM) components play an important role in the regulation and maintenance of neural stem cells (NSCs). Laminin, an ECM component, is a key factor in promoting axonal regeneration and differentiation of NSCs. Since NSCs cannot be easily harvested with low morbidity, adipose‐derived stem cells have been suggested for therapeutic applications of neural tissue damage. Therefore, the potential of laminin‐111 to enhance the production of neurotrophin‐3 (NT3) and its related signal pathways from canine adipose tissue‐derived stem cells (cADSCs) was investigated. Laminin‐111 enhanced NT3 production in neural induction medium (NIM). Treatment of NIM or laminin‐111 on cADSCs distinctively changed integrin β1 mRNA and protein expression levels. In addition, laminin‐111‐induced Akt phosphorylation was inhibited by integrin β1 small interfering RNA (siRNA) and PI3K inhibitors (LY294002 and wortmannin). Furthermore, increased phosphorylations of mTOR and p70S6K by laminin‐111 were blocked by inhibitors or specific siRNA, respectively. Moreover, laminin‐111‐induced NT3 production was blocked by these inhibitors. In experiments to induce the differentiation of cADSCs, laminin‐111 increased the expression of neuronal markers β 3 tubulin, MAP2, and NeuN, and decreased the expression of the NSC markers nestin and vimentin. In conclusion, laminin‐111 increases NT3 production through Akt, mTOR, and p70S6K pathways via integrin β1 in cADSCs cultured in NIM. J. Cell. Physiol. 226: 3251–3260, 2011.