Neurogenesis in Stroke Recovery

Abstract

Stroke, resulting from limited blood flow to the brain, is one of the most important causes of morbidity and mortality worldwide. Stroke is classified as ischemic, due to lack of blood flow, or hemorrhagic, due to bleeding. Because 87 % of strokes are classified as ischemic, this type will be the predominant focus of this review. Except for thrombolytic therapy, there is no established treatment to reduce the neurological deficits caused by ischemic stroke. Therefore, it is necessary to develop new therapeutic strategies designed to improve neurological functions after ischemic stroke. Recently, therapies to enhance neurogenesis after ischemic stroke have been investigated. However, these approaches have not led to successful clinical outcomes. This review addresses the pathophysiology of stroke, neurogenesis after stroke, and how to stimulate these processes based on the current literature. Finally, ongoing clinical trials to improve neurological functions after stroke by enhancing neurogenesis are discussed in this review.

Current Opinion on the Role of Neurogenesis in the Therapeutic Strategies for Alzheimer Disease, Parkinson Disease, and Ischemic Stroke; Considering Neuronal Voiding Function

“…Therefore, determination of a clear mechanism in the development and activation of endogenous neurogenesis may be an ideal option for screening and treatment of neurological diseases. However, a therapeutic strategy for the treatment of neurologic diseases using endogenous neurogenesis is limited because of the continuous decline in the number and capacity of NCSs due to the disease process and aging [6,23]. Consequently, many studies have attempted to evaluate the efficacy of exogenous stem cell transplantation into the brains of patients with neurologic diseases [24-28].…”

“…Consequently, many studies have attempted to evaluate the efficacy of exogenous stem cell transplantation into the brains of patients with neurologic diseases [24-28]. However, unexpected complications have been reported including the inability of these cells to differentiate into specific types of neuron, and the risk of malignant transformation and immune rejection after NSCs transplantation [6]. …”

“…Decreased oxygen delivery results in activation of cellular anaerobic metabolism leading to the depletion of glucose, which is the only source of energy in the brain. This ischemic cascade causes neuronal damage and ionic pump failure in the brain due to energy depletion, and ultimately leads to necrosis and apoptosis of neurons and glial cells resulting in irreversible injury to core regions with partially reversible damage in the surrounding penumbra zone [6]. …”

“…The pathophysiology of IS is provoked by a reduction or complete blockage in blood supply to the brain, leading to dysfunction in the ischemic area [6]. The main causes of ischemia are thrombosis, embolism, systemic hypoperfusion, or lacunar infarction from small vessel disease.…”

Mechanisms, Imaging, and Therapy in Stroke Recovery

“…The first two papers focus on the mechanisms of neurogenesis and axonal repair after stroke. Koh et al [25] discuss ways to stimulate neurogenesis after stroke, and survey ongoing clinical trials focusing on enhancing neurogenesis. Egawa et al [26] discuss the mechanisms underlying axonal degeneration and potential targets that may promote axonal regeneration after brain injury.…”