Cell-based therapy for ischemic stroke

Abstract

Introduction: Stroke is a major cause of mortality and disability in adults worldwide. Unfortunately, current therapy which targets vessel recanalization has a narrow treatment window, and at this time neuroprotective approaches are not effective for stroke treatment. However, after stroke the parenchymal and endothelial cells in the central nervous system (CNS) respond in concert to ischemic stressors and create a microenvironment in which successful recovery may ensue. Neurogenesis, synaptogenesis, axonal sprouting, glial cell activation, angiogenesis and vascular remodeling within the brain and the spinal cord are stimulated post stroke. Cell based-therapy amplifies these endogenous restorative effects within the CNS to promote functional outcome.

Areas covered: This article reviews current knowledge of cell-based therapy in the adult brain after stroke, including transplanted cell type, benefits and risks, with an emphasis on mechanisms of action.

Expert opinion: Experimental studies and clinical trials with cell-based therapy in stroke appear promising. Cell-based therapy is not intended for the replacement of damaged cells, but for the remodeling of the CNS by promoting neuroplasticity, angiogenesis and immunomodulation. However, there are risks associated with the use of cell-based therapy, and adequate evaluation of these potential risks is a prerequisite before clinical application for stroke patients.

Figure 1. A schematic diagram of the mechanisms underlying the benefits of cell-based therapy for stroke

After transplantation, grafted cells migrate into the lesion boundary zone by attracting factors, for example increased stromalderived factor-1 (SDF-1). Grafted cells promote neurogenesis, angiogenesis, astrogenesis and oligodendrogenesis, and immunomodulation. All these interactive restorative events contribute to the improvement in functional outcome.