Optimization of time for neural stem cells transplantation for brain stroke in rats

Routes and methods of neural stem cells injection in cerebral ischemia

Cerebral ischemia is a serious cerebrovascular disease with the characteristics of high morbidity, disability, and mortality. Currently, stem cell therapy has been extensively applied to a wide range of diseases, including neurological disorders, autoimmune deficits, and other diseases. Transplantation therapy with neural stem cells (NSCs) is a very promising treatment method, which not only has anti-inflammatory, antiapoptotic, promoting angiogenesis, and neurogenesis effects, but also can improve some side effects related to thrombolytic therapy. NSCs treatment could exert protective effects in alleviating cerebral ischemia-induced brain damage and neurological dysfunctions. However, the different injection routes and doses of NSCs determine diverse therapeutic efficacy. This review mainly summarizes the various injection methods and injection effects of NSCs in cerebral ischemia, as well as proposes the existing problems and prospects of NSCs transplantation.

Immunomodulation: The next target of mesenchymal stem cell-derived exosomes in the context of ischemic stroke

Ischemic stroke (IS) is the most prevalent form of brain disease, characterized by high morbidity, disability, and mortality. However, there is still a lack of ideal prevention and treatment measures in clinical practice. Notably, the transplantation therapy of mesenchymal stem cells (MSCs) has been a hot research topic in stroke. Nevertheless, there are risks associated with this cell therapy, including tumor formation, coagulation dysfunction, and vascular occlusion. Also, a growing number of studies suggest that the therapeutic effect after transplantation of MSCs is mainly attributed to MSC-derived exosomes (MSC-Exos). And this cell-free mediated therapy appears to circumvent many risks and difficulties when compared to cell therapy, and it may be the most promising new strategy for treating stroke as stem cell replacement therapy. Studies suggest that suppressing inflammation via modulation of the immune response is an additional treatment option for IS. Intriguingly, MSC-Exos mediates the inflammatory immune response following IS by modulating the central nervous system, the peripheral immune system, and immunomodulatory molecules, thereby promoting neurofunctional recovery after stroke. Thus, this paper reviews the role, potential mechanisms, and therapeutic potential of MSC-Exos in post-IS inflammation in order to identify new research targets.

Neural Stem Cells Therapy for Ischemic Stroke: Progress and Challenges

Ischemic stroke, with its high morbidity and mortality, is the most common cerebrovascular accident and results in severe neurological deficits. Despite advances in medical and surgical intervention, post-stroke therapies remain scarce, which seriously affects the quality of life of patients. Over the past decades, stem cell transplantation has been recognized as very promising therapy for neurological diseases. Neural stem cell (NSC) transplantation is the optimal choice for ischemic stroke as NSCs inherently reside in the brain and can potentially differentiate into a variety of cell types within the central nervous system. Recent research has demonstrated that NSC transplantation can facilitate neural recovery after ischemic stroke, but the mechanisms still remain unclear, and basic/clinical studies of NSC transplantation for ischemic stroke have not yet been thoroughly elucidated. We thus, in this review, provide a futher understanding of the therapeutic role of NSCs for ischemic stroke, and evaluate their prospects for future application in clinical patients of ischemic stroke.

Dynamic behavior and stabilization of brain cell reconstitution after stroke under the proliferation and differentiation processes for stem cells

Stem cells play a critical role in regulatory operations, overseeing tissue regeneration and tissue homeostasis. In this paper, a mathematical model is proposed and analyzed to study the impact of stem cell transplantation on the dynamical behavior of stroke therapy, which is assumed to be based on transplanting dead brain cells following a stroke. We transform the method of using hierarchical cell systems into a method of using different compartment variables by using ordinary differential equations, each of which elucidates a well-defined differentiation stage along with the effect of mature cells in improving the brain function after a stroke. Stem cells, progenitor cells, and the impacts of the stem cells transplanted on brain cells are among the variables considered. The model is studied analytically and solved numerically using the fourth-order Runge-Kutta method. We analyze the structure of equilibria, the ability of neural stem cells to proliferate and differentiate, and the stability properties of equilibria for stem cell transplantation. The model is considered to be stable after transplantation if the stem cells and progenitor cells differentiate into mature nerve cells in the brain. The results of the model analysis and simulation facilitate the identification of various biologically probable parameter sets that can explain the optimal time for stem cell replacement of damaged brain cells. Associating the classified parameter sets with recent experimental and clinical findings contributes to a better understanding of therapeutic mechanisms that promote the reconstitution of brain cells after an ischemic stroke.

Mechanism of miR-320 in Regulating Biological Characteristics of Ischemic Cerebral Neuron by Mediating Nox2/ROS Pathway

This study aimed to explore the mechanism of miR-320 in regulating biological characteristics of ischemic cerebral neuron by mediating Nox2/ROS pathway. Primary neurons were cultured and grouped: normal group (normal primary neurons), negative control (NC) group (ischemic primary neurons, transfected with negative control plasmid), model group (ischemic primary neurons), miR-320 mimic group (ischemic primary neurons, transfected with miR-320-overexpressed plasmid), Nox2 vector group (ischemic primary neurons, transfected with Nox2-overexpressed plasmid), and miR-320 mimic + Nox2 vector group (ischemic primary neurons, co-transfected with miR-320- and Nox2-overexpressed plasmid). Dual-luciferase reporter assay showed that there was the target relationship between miR-320 and Nox2. miR-320 expression was significantly decreased, and Nox2 expression was significantly increased in the rest groups compared with normal group (both P < 0.05). There was a co-localization of miR-320 and Nox2 in the cytoplasm. Cell proliferation, contents of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX), and mRNA and protein expressions of Ki67, Bcl-2, and c-myc were significantly declined, and apoptosis rate, contents of malondialdehyde (MDA) and reactive oxygen species (ROS), and caspase-3 mRNA and protein expressions were significantly increased in the rest groups compared with normal group (all P < 0.05). miR-320 promoted cell proliferation; increased contents of SOD, CAT, and GSH-PX; and declined apoptosis and contents of MDA and ROS. Moreover, miR-320 could affect the regulation of Nox2/ROS pathway on ischemic cerebral neuron by negatively regulating Nox2 expression. Overexpressed miR-320 affects the proliferation, apoptosis, and oxidative stress injury of ischemic cerebral neuron by inhibiting Nox2/ROS pathway.

Neural Stem Cells Transfected with Reactive Oxygen Species-Responsive Polyplexes for Effective Treatment of Ischemic Stroke

Neural stem cells (NSCs), capable of ischemia-homing, regeneration, and differentiation, exert strong therapeutic potentials in treating ischemic stroke, but the curative effect is limited in the harsh microenvironment of ischemic regions rich in reactive oxygen species (ROS). Gene transfection to make NSCs overexpress brain-derived neurotrophic factor (BDNF) can enhance their therapeutic efficacy; however, viral vectors must be used because current nonviral vectors are unable to efficiently transfect NSCs. The first polymeric vector, ROS-responsive charge-reversal poly[(2-acryloyl)ethyl(p-boronic acid benzyl)diethylammonium bromide] (B-PDEA), is shown here, that mediates efficient gene transfection of NSCs and greatly enhances their therapeutics in ischemic stroke treatment. The cationic B-PDEA/DNA polyplexes can effectively transfect NSCs; in the cytosol, the B-PDEA is oxidized by intracellular ROS into negatively charged polyacrylic acid, quickly releasing the BDNF plasmids for efficient transcription and secreting a high level of BDNF. After i.v. injection in ischemic stroke mice, the transfected NSCs (BDNF-NSCs) can home to ischemic regions as efficiently as the pristine NSCs but more efficiently produce BDNF, leading to significantly augmented BDNF levels, which in turn enhances the mouse survival rate to 60%, from 0% (nontreated mice) or ≈20% (NSC-treated mice), and enables more rapid and superior functional reconstruction.

Preconditioned neurons with NaB and nicorandil, a favorable source for stroke cell therapy

Poor survival of stem cells in the harsh microenvironment at the site of stroke, especially during acute phase of injury, remains a serious obstacle to achieve the desired prognosis. We hypothesized that combined treatment of neural stem cells (NSCs) with small molecules would precondition them to become robust and survive better as compared with the native nonpreconditioned cells. Mouse ganglionic NSCs were isolated, cultured, and characterized. The cells were preconditioned by treatment with sodium butyrate (NaB) and nicorandil (Nico) and transplanted in an experimentally induced stroke model. Sham-operated animals without treatment or animals with experimental stroke treated with basal medium, native NSCs, NSCs preconditioned with NaB or Nico alone were used as controls. The tissue samples and cells with different treatments were used to measure brain-tissue-derived neurotrophic factor (BDNF) level and the activity of phosphatidylinositol-3 kinase (PI3K), apurinic/apyrimidinic endonuclease 1 (APE1), and nuclear factor-κB (NF-κB) p50 both in vitro and in vivo, respectively. Additionally, survival of the cells and recovery indices for stroke were studied. The combined treatment with NaB + Nico resulted in increased BDNF level and higher PI3K, APE1, and the downstream NF-κB activation, which were blocked by pretreatment with their respective inhibitors. Donor cell survival increased postengraftment as assessed by 5-bromo-2'-deoxyuridine immunostaining and reduced Terminal deoxynucleotide transferase dUTP Nick End Labeling positivity at the site of engraftment. There was reduction in proinflammatory cytokines and infiltration of both GFAP + and CD68 + at the injury site. There was reduction in the infarct size and neurological function was preserved in the preconditioned cell treatment group. Our preconditioning approach with small molecules effectively improved the survival as well as functionality of NSCs.

Neural stem cell therapy for subacute and chronic ischemic stroke

Neural stem cells (NSCs) play vital roles in brain homeostasis and exhibit a broad repertoire of potentially therapeutic actions following neurovascular injury. One such injury is stroke, a worldwide leading cause of death and disability. Clinically, extensive injury from ischemic stroke results from ischemia-reperfusion (IR), which is accompanied by inflammation, blood-brain barrier (BBB) damage, neural cell death, and extensive tissue loss. Tissue plasminogen activator (tPA) is still the only US Food and Drug Administration-approved clot-lysing agent. Whereas the thrombolytic role of tPA within the vasculature is beneficial, the effects of tPA (in a non-thrombolytic role) within the brain parenchyma have been reported as harmful. Thus, new therapies are needed to reduce the deleterious side effects of tPA and quickly facilitate vascular repair following stroke. The Stroke Treatment Academic Industry Roundtable (STAIR) recommends that stroke therapies "focus on drugs/devices/treatments with multiple mechanisms of action and that target multiple pathways". Thus, based on multifactorial ischemic cascades in various stroke stages, effective stroke therapies need to focus on targeting and ameliorating early IR injury as well as facilitating angiogenesis, neurogenesis, and neurorestorative mechanisms following stroke. This review will discuss the preclinical perspectives of NSC transplantation as a promising treatment for neurovascular injury and will emphasize both the subacute and chronic phase of ischemic stroke.