The combination of stem cell factor and granulocyte-colony stimulating factor for chronic stroke treatment in aged animals

BACKGROUND: Stroke occurs more frequently in the elderly population and presents the number one leading cause of persistent disability worldwide. Lack of effective treatment to enhance brain repair and improve functional restoration in chronic stroke, the recovery phase of stroke, is a challenging medical problem to be solved in stroke research. Our early study has revealed the therapeutic effects of stem cell factor (SCF) in combination with granulocyte-colony stimulating factor (G-CSF) (SCF+G-CSF) on chronic stroke in young animals. However, whether this treatment is effective and safe to the aged population remains to be determined. METHODS: Cortical brain ischemia was produced in aged C57BL mice or aged spontaneously hypertensive rats. SCF+G-CSF or equal volume of vehicle solution was subcutaneously injected for 7 days beginning at 3–4 months after induction of cortical brain ischemia. Using the approaches of biochemistry assays, flow cytometry, pathology, and evaluation of functional outcome, several doses of SCF+G-CSF have been examined for their safety and efficiency on chronic stroke in aged animals. RESULTS: All tested doses did not show acute or chronic toxicity in the aged animals. Additionally, SCF+G-CSF treatment in chronic stroke of aged animals mobilized bone marrow stem cells and improved functional outcome in a dose-dependent manner. CONCLUSIONS: SCF+G-CSF treatment is a safe and effective approach to chronic stroke in the aged condition. This study provides important information needed for developing a new therapeutic strategy to improve the health of older adults with chronic stroke.