Strategies to Improve the Efficiency of Transplantation with Mesenchymal Stem Cells for the Treatment of Ischemic Stroke: A Review of Recent Progress

Mesenchymal stem cells and their extracellular vesicles as emerging therapeutic tools in the treatment of ischemic stroke

Ischemic stroke (IS) is a neurological condition characterized by severe long-term consequences and an unfavorable prognosis for numerous patients. Despite advancements in stroke treatment, existing therapeutic approaches possess certain limitations. However, accumulating evidence suggests that mesenchymal stem/stromal cells (MSCs) hold promise as a potential therapy for various neurological disorders, including IS, owing to their advantageous properties, such as immunomodulation and tissue regeneration. Additionally, MSCs primarily exert their therapeutic effects through the release of extracellular vesicles (EVs), highlighting the significance of their paracrine activities. These EVs are small double-layered phospholipid membrane vesicles, carrying a diverse cargo of proteins, lipids, and miRNAs that enable effective cell-to-cell communication. Notably, EVs have emerged as attractive substitutes for stem cell therapy due to their reduced immunogenicity, lower tumorigenic potential, and ease of administration and handling. Hence, this review summarizes the current preclinical and clinical studies performed to investigate the safety and therapeutic potential of MSCs and their EVs derived from different sources, including bone marrow, adipose tissue, umbilical cord blood, and Wharton's jelly in IS.

Uwhangchungsimwon Inhibits Oxygen Glucose Deprivation/Re-Oxygenation-Induced Cell Death through Neuronal VEGF and IGF-1 Receptor Signaling and Synaptic Remodeling in Cortical Neurons

Uwhangchungsimwon (UCW), a multi-component herbal product, has long been used to treat vascular diseases such as headache, dizziness, high blood pressure, and stroke. Though the prophylactic actions of UCW are well known, insufficient experimental evidence exists on its effectiveness against stroke. Here, we investigated the mechanism underlying the efficacy of UCW in oxygen glucose deprivation/re-oxygenation (OGD/R)-injury to the primary cortical neurons using an in vitro ischemia model. Neurons secrete vascular endothelial growth factor (VEGF), which acts as a neurotrophic factor in response to an ischemic injury. VEGF modulates neuroprotection and axonal outgrowth by activating the VEGF receptors and plays a critical role in vascular diseases. In this study, cortical neurons were pretreated with UCW (2, 10, and 50 µg/mL) for 48 h, incubated in oxygen-glucose-deprived conditions for 2 h, and further reoxygenated for 24 h. UCW effectively protected neurons from OGD/R-induced degeneration and cell death. Moreover, the role of UCW in sustaining protection against OGD/R injury is associated with activation of VEGF-VEGFR and insulin-like growth factor 1 receptor expression. Therefore, UCW is a potential herbal supplement for the prevention of hypoxic-ischemic neuronal injury as it may occur after stroke.

Mesenchymal Stromal Cells in Ischemic Brain Injury

Ischemic brain injury represents a major cause of death worldwide with limited treatment options with a narrow therapeutic window. Accordingly, novel treatments that extend the treatment from the early neuroprotective stage to the late regenerative phase may accommodate a much larger number of stroke patients. To this end, stem cell-based regenerative therapies may address this unmet clinical need. Several stem cell therapies have been tested as potentially exhibiting the capacity to regenerate the stroke brain. Based on the long track record and safety profile of transplantable stem cells for hematologic diseases, bone marrow-derived mesenchymal stromal cells or mesenchymal stromal cells have been widely tested in stroke animal models and have reached clinical trials. However, despite the translational promise of MSCs, probing cell function remains to be fully elucidated. Recognizing the multi-pronged cell death and survival processes that accompany stroke, here we review the literature on MSC definition, characterization, and mechanism of action in an effort to gain a better understanding towards optimizing its applications and functional outcomes in stroke.