http://www.ncbi.nlm.nih.gov/pubmed/22405262
Abstract
The therapeutic efficacy of cell-based therapy after stroke can be enhanced by making the host brain tissue more receptive to the administered cells which thereby facilitates brain plasticity. We hypothesized that Simvastatin increases human umbilical cord blood cell (HUCBC) migration into the ischemic brain and promotes brain plasticity and neurological functional outcome after stroke. Rats were subjected to 2 hour middle cerebral artery occlusion (MCAo) and administered sub-therapeutic doses of Simvastatin (0.5 mg/kg, gavaged daily for 7 days), HUCBCs (1×10⁶, one time injection via tail vein) or combination Simvastatin with HUCBCs starting at 24 hours after stroke. Combination treatment of stroke showed an interactive effect in improvement of neurological outcome compared with Simvastatin- or HUCBC-monotherapy groups. In addition, combination treatment significantly increased brain-derived neurotrophic factor/TrkB expression and the number of engrafted-HUCBCs in the ischemic brain compared with HUCBC-monotherapy. The number of engrafted-HUCBCs were significantly correlated with functional outcome (modified neurological severity score). Combination treatment significantly increased neurogenesis and synaptic plasticity in the ischemic brain, and promoted neuroblast migration in cultured subventricular zone explants. Using primary cultured neurons (PCNs), we found that combination treatment enhanced neurite outgrowth compared with non-treatment control, Simvastatin- or HUCBC-supernatant monotherapy. Inhibition of TrkB significantly attenuated combination treatment induced neurite outgrowth. Our data indicate that combination Simvastatin and HUCBC treatment of stroke increases BDNF/TrkB expression, enhances HUCBC migration into the ischemic brain, amplifies endogenous neurogenesis, synaptic plasticity and axonal growth, and thereby improves functional outcome after stroke.
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