Targeted delivery of growth factors in ischemic stroke animal models.

INTRODUCTION: Ischemic stroke is caused by reduced blood supply and leads to loss of brain function. The reduced oxygen and nutrient supply stimulates various physiological responses, including induction of growth factors. Growth factors prevent neuronal cell death, promote neovascularization, and induce cell growth. However, the concentration of growth factors is not sufficient to recover brain function after the ischemic damage, suggesting that delivery of growth factors into the ischemic brain may be a useful treatment for ischemic stroke. AREAS COVERED: In this review, various approaches for the delivery of growth factors to ischemic brain tissue are discussed, including local and targeting delivery systems. EXPERT OPINION: To develop growth factor therapy for ischemic stroke, important considerations should be taken into account. First, growth factors may have possible side effects. Thus, concentration of growth factors should be restricted to the ischemic tissues by local administration or targeted delivery. Second, the duration of growth factor therapy should be optimized. Growth factor proteins may be degraded too fast to have a high enough therapeutic effect. Therefore, delivery systems for controlled release or gene delivery may be useful. Third, the delivery systems to the brain should be optimized according to the delivery route.