Stem Cell Therapy to Improve Nerve Regeneration and Functional Recovery in Vascular Composite Allotransplantation (VCA)

Background: Stem cell transplantation (Tx) has emerged as a promising new experimental treatment for stroke; understanding its mechanism of action will facilitate the translation of stem cell therapy to the clinic. The ultimate change in brain plasticity is manifested at the synaptic level, however, the synaptic remodeling after stem cell therapy remains unknown. Here we evaluate the effect of transplanted human neural progenitor cells (hNPCs) on the peri-infarct synaptic remodeling in the post-ischemic brain. Materials and Methods: We use array tomography, a high-resolution proteomic imaging method, to determine how hNPCs affect the number and subtype of glutamate and GABA synapses after stroke. Vehicle or hNPCs were transplanted into the ischemic cortex of Nude rats 7 days after distal middle cerebral artery occlusion. Neurological recovery was assessed weekly using a battery of behavioral tests. The arrays of serial ultrathin sections (70 nm), removed from the peri-infarct cortex at 1 and 4 weeks post-Tx, were stained using multiple synaptic markers and imaged in cortical layer 2/3 and 5. Computational analysis of the resultant staining pattern was used to identify and quantify subtypes of glutamate and GABA synapses. Results: Tx of hNPCs significantly improved behavioral recovery after stroke compared to vehicle-treated rats (4 weeks post-transplantation; p<0.01) without altering the infarct size. hNPC-treated rats had a higher density of VGluT1-containing glutamate synapses (0.223 vs 0.185 synapses/μm3, p<0.05), and GluA2-containing glutamate synapses (0.091 vs 0.069 synapses/μm3, p<0.05) in layer 5 at 4 weeks post-Tx, compared to vehicle-treated rats. However, hNPCs had did not alter total number of glutamate synapses. This synaptic increase was cortical layer-specific observed in layer 5 but not .in layer 2/3. hNPCs had no detectable effect on the density of GABA synapses in either layer 5 or 2/3 at 1 week or 4 weeks post-Tx. Conclusions: These results provide novel new information about the organization of synaptic circuitry and its plasticity after stem cell therapy. These data suggest that stem cells alter the subunit composition of glutamate synapses after stroke and this is coincident with stem cell-induced functional recovery.

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Mesenchymal Stem Cell Therapy for Nerve Regeneration and Immunomodulation After Composite Tissue Allotransplantation

10.21236/ada559244 ◽

2011 ◽

Author(s):

W. P. Lee

Keyword(s):

Stem Cell ◽

Mesenchymal Stem Cell ◽

Cell Therapy ◽

Nerve Regeneration ◽

Stem Cell Therapy ◽

Composite Tissue Allotransplantation ◽

Mesenchymal Stem Cell Therapy ◽

Composite Tissue

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Abstract P815: Decoding the Cross-Talk Between Grafted Neural Stem Cells and Host Brain to Predict the Molecular Mechanisms of Stem Cell-Induced Functional Recovery After Stroke

Stroke ◽

10.1161/str.52.suppl_1.p815 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Seth S Tigchelaar ◽

Ricardo L Azevedo-Pereira ◽

Chen Dong ◽

xibin liang ◽

Tonya Bliss ◽

...

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Cell Therapy ◽

Neural Stem Cells ◽

Brain Tissue ◽

Stem Cell Therapy ◽

Functional Recovery ◽

The United States ◽

Paracrine Factors ◽

Osmotic Pumps

Stroke is a leading cause of long-term disability and death in the united states. The development of new therapies for stroke are sorely needed. There is great hope that stem cell therapy will create a paradigm shift in the treatment of stroke patients. A barrier to ensuring clinical success of stem cell therapy is the paucity of understanding of the mechanisms by which stem cells exert their beneficial effects. Using a novel mRNA purification method, we identified 50 genes encoding extracellular space proteins, expressed by human neural stem cells (hNSCs) whose expression positively correlated with functional recovery. In this study, we focus on one of the paracrine factors from grafted hNSCs that correlated best with functional recovery, to investigate its therapeutic potential in promoting recovery after stroke. Male nude rats underwent stroke using the distal middle cerebral artery occlusion (dMCAo) model. One week following stroke, osmotic pumps were prepared and loaded with recombinant MTN-2. The osmotic pumps were inserted into the peri-infarct area and infused recombinant MTN-2 for 5 days. Post-stroke, animals were assessed for functional recovery for 5 weeks using both the Montoya staircase test and the whisker-paw reflex test to assess for forelimb function, dexterity, side bias, and placing deficits. After 5 weeks, brain tissue was isolated to assess glial cell morphology. Brain sections were stained with GFAP and IBA1 to visualize astrocytes and microglia, respectively. Confocal images were processed and analyzed using the Bitplane Imaris image analysis software. Output measurements of number of cells/mm2, cell volume, cell branching, and process length and thickness were obtained to characterize the changes in astrocytic and microglial response to injury and paracrine factor treatment. By identifying paracrine factors that are responsible for the regeneration of brain tissue following implantation of hNSCs in stroke brain, this work will increase the likelihood of successful clinical translation of stem cell therapy for stroke. Moreover, elucidating these molecular pathways important for brain recovery may ultimately identify novel therapeutic targets and offer hope to millions of Americans who live with the devastating effects of stroke.

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