Stem Cells In Ischemic Stroke Research Articles

Preclinical safety and efficacy evaluation of the intrathecal transplantation of GMP-grade human umbilical cord mesenchymal stem cells for ischemic stroke

Intrathecal administration of human umbilical cord mesenchymal stem cells may be a promising approach for the treatment of stroke, but its safety, effectiveness, and mechanism remain to be elucidated. In this study, good manufacturing practice–grade human umbilical cord mesenchymal stem cells (5 × 105 and 1 × 106 cells) and saline were administered by cerebellomedullary cistern injection 72 hours after stroke induced by middle cerebral artery occlusion in rats. The results showed (1) no significant difference in mortality or general conditions among the three groups. There was no abnormal differentiation or tumor formation in various organs of rats in any group. (2) Compared with saline-treated animals, those treated with human umbilical cord mesenchymal stem cells showed significant functional recovery and reduced infarct volume, with no significant differences between different human umbilical cord mesenchymal stem cell doses. (3) Human umbilical cord mesenchymal stem cells were found in the ischemic brain after 14 and 28 days of follow-up, and the number of positive cells significantly decreased over time. (4) Neuronal nuclei expression in the human umbilical cord mesenchymal stem cell group was greater than that in the saline group, while glial fibrillary acidic protein and ionized calcium binding adaptor molecule 1 expression levels decreased. (5) Human umbilical cord mesenchymal stem cell treatment increased the number of CD31+ microvessels and doublecortin-positive cells after ischemic stroke. Human umbilical cord mesenchymal stem cells also upregulated the expression of CD31+/Ki67+. (6) At 14 days after intrathecal administration, brain-derived neurotrophic factor expression in the peri-infarct area and the concentrations of brain-derived neurotrophic factor in the cerebrospinal fluid in both human umbilical cord mesenchymal stem cell groups were significantly greater than those in the saline group and persisted until the 28th day. Taken together, these results indicate that the intrathecal administration of human umbilical cord mesenchymal stem cells via cerebellomedullary cistern injection is safe and effective for the treatment of ischemic stroke in rats. The mechanisms may include alleviating the local inflammatory response in the peri-infarct region, promoting neurogenesis and angiogenesis, and enhancing the production of neurotrophic factors.

SIRT-1/RHOT-1/PGC-1α loop modulates mitochondrial biogenesis and transfer to offer resilience following endovascular stem cell therapy in ischemic stroke

Current clinical interventions for stroke majorly involve thrombolysis or thrombectomy, however, cessation of the progressive deleterious cellular cascades post-stroke and long-term neuroprotection are yet to be explored. Mitochondria are highly vulnerable organelles and their dysfunction is one of the detrimental consequences following stroke. Mitochondria dysregulation activate unfavourable cellular events over a period of time that leads to the collapse of neuronal machinery in the brain. Hence, strategies to protect and replenish mitochondria in injured neurons may be useful and needs to be explored. Stem cell therapy in ischemic stroke holds a great promise. Past studies have shown beneficial outcomes of endovascularly delivered stem cells in both pre-clinical and clinical settings. Intra-arterial (IA) administration can provide more cells to the stroke foci and affected brain regions than intravenous administration. Supplying new mitochondria to the stroke-compromised neurons either in the core or penumbra by infused stem cells can help increase their survival and longevity. Previously, our lab has demonstrated that IA 1∗105 mesenchymal stem cells (MSCs) in rats were safe, efficacious and rendered neuroprotection by regulating neuronal calcineurin, modulating sirtuin1(SIRT-1) mediated inflammasome signaling, ameliorating endoplasmic reticulum-stress, alleviation of post-stroke edema and reducing cellular apoptosis. To explore further, our present study aims to investigate the potential of IA MSCs in protecting and replenishing mitochondria in the injured neurons post-stroke and the involvement of SIRT-1/RHOT-1/PGC-1α loop towards mitochondria transfer, biogenesis, and neuroprotection. This study will open new avenues for using stem cells for ischemic stroke in clinics as one of the future adjunctive therapies.

Stereotactically intracerebral transplantation of neural stem cells for ischemic stroke attenuated inflammatory responses and promoted neurogenesis: an experimental study with monkeys.

Ischemic stroke is a common neurovascular disorder with high morbidity and mortality. However, the underlying mechanism of stereotactically intracerebral transplantation of human neural stem cells (hNSCs) is not well elucidated. Four days after ischemic stroke induced by Rose Bengal photothrombosis, seven cynomolgus monkeys were transplanted with hNSCs or vehicles stereotactically and followed up for 84 days. Behavioral assessments, magnetic resonance imaging, blood tests, and pathological analysis were performed before and after treatment. The proteome profiles of the left and right precentral gyrus and hippocampus were evaluated. Extracellular vesicle micro-RNA (miRNA) from the peripheral blood was extracted and analyzed. hNSC transplantation reduced the remaining infarcted lesion volume of cynomolgus monkeys with ischemic stroke without remarkable side effects. Proteomic analyses indicated that hNSC transplantation promoted GABAergic and glutamatergic neurogenesis and restored the mitochondrial electron transport chain function in the ischemic infarcted left precentral gyrus or hippocampus. Immunohistochemical staining and quantitative real-time reverse transcription PCR confirmed the promoting effects on neurogenesis and revealed that hNSCs attenuated post-infarct inflammatory responses by suppressing resident glia activation and mediating peripheral immune cell infiltration. Consistently, miRNA-sequencing revealed the miRNAs that were related to these pathways were downregulated after hNSC transplantation. This study indicates that hNSCs can be effectively and safely used to treat ischemic stroke by promoting neurogenesis, regulating post-infarct inflammatory responses, and restoring mitochondrial function in both the infarct region and hippocampus.

Priming and Combined Strategies for the Application of Mesenchymal Stem Cells in Ischemic Stroke: A Promising Approach.

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Tissue plasminogen activator (tPA) administration and mechanical thrombectomy are the main treatments but have a narrow time window. Mesenchymal stem cells (MSCs), which are easily scalable in vitro and lack ethical concerns, possess the potential to differentiate into various types of cells and secrete a great number of growth factors for neuroprotection and regeneration. Moreover, MSCs have low immunogenicity and tumorigenic properties, showing safety and preliminary efficacy both in preclinical studies and clinical trials of IS. However, it is unlikely that MSC treatment alone will be sufficient to maximize recovery due to the low survival rate of transplanted cells and various mechanisms of ischemic brain damage in the different stages of IS. Preconditioning was used to facilitate the homing, survival, and secretion ability of the grafted MSCs in the ischemic region, while combination therapies are alternatives that can maximize the treatment effects, focusing on multiple therapeutic targets to promote stroke recovery. In this case, the combination therapy can yield a synergistic effect. In this review, we summarize the type of MSCs, preconditioning methods, and combined strategies as well as their therapeutic mechanism in the treatment of IS to accelerate the transformation from basic research to clinical application.

Efficacy and safety of intravenous mesenchymal stem cells for ischemic stroke patients, a systematic review and meta-analysis

BackgroundClinical trials have evaluated the efficacy of intravenous mesenchymal stem cells (MSCs) for acute and subacute ischemic stroke. Therefore, we conducted this meta-analysis to investigate the efficacy and safety of intravenous MSC treatments compared to placebo for acute and subacute ischemic stroke patients.MethodsWe searched PubMed, SCOPUS, Web of Science, and Cochrane CENTRAL for randomized controlled trials evaluating any clinical trials of intravenous MSCs for acute and subacute ischemic stroke patients. The efficacy outcomes of this study were the rates of improvement in National Institutes of Health Stroke Scale (NIHSS) scores, good scores on the modified Rankin Scale (mRS), and Barthel Index (BI) scores, while the safety outcomes were the rates of mortality and stroke recurrence. We compared intravenous MSC and placebo treatments on a fixed-effect meta-analysis model in R software.ResultsFour randomized controlled studies involving 97 patients were included in the analysis. In the meta-analysis, MSC treatments were superior to placebo treatments in good mRS (MD −0.95, 95% CI [−1.39, −0.52]) or BI (MD 21.36, 95% CI [9.96, 32.75]) scores, and MSC treatments were not superior to placebo treatments in the rate of improvement of the NIHSS scores (MD −1.81, 95% CI [−4.123, 0.494]). MSCs were associated with neither decreased mortality nor stroke recurrence (risk ratio 0.58 and 0.59, respectively; p-value = 0.51 and p-value = 0.533, respectively).ConclusionFor patients with acute and subacute ischemic stroke who are eligible for further damage to neural tissue, MSCs achieve high efficacy and acceptable safety.Systematic review registrationProspero, unique ID: CRD42023457655.

Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke: current evidence and future perspectives.

Ischemic stroke is a leading cause of death and disability worldwide, with an increasing trend and tendency for onset at a younger age. China, in particular, bears a high burden of stroke cases. In recent years, the inflammatory response after stroke has become a research hotspot: understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment. This review summarizes several major cells involved in the inflammatory response following ischemic stroke, including microglia, neutrophils, monocytes, lymphocytes, and astrocytes. Additionally, we have also highlighted the recent progress in various treatments for ischemic stroke, particularly in the field of stem cell therapy. Overall, understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes. Stem cell therapy may potentially become an important component of ischemic stroke treatment.

Bibliometric Analysis of Stem Cells in Ischemic Stroke (2001-2022): Trends, Hotspots and Prospects.

Background: Ischemic stroke is a common cerebrovascular accident with a high risk of neurological deficits. Stem cell therapy has progressively attracted the interest of scientists and clinicians due to the benefits of promoting neural regeneration and regulating the microenvironment surrounding the lesion after ischemic stroke. Our study aimed to evaluate the development trends and research hotspots in the field of stem cells and ischemic stroke. Materials and methods: Publications related to stem cells and ischemic stroke were retrieved from the Web of Science from 2001 to 2022. Data analysis and mapping were performed using VOSviewer, Citespace and ImageGP. Results: In total, 1932 papers were included in the analysis. Publications have steadily increased over the past 22 years. China has contributed the maximum number of publications, whereas the USA ranked first in the total number of citations and was considered the center of the international collaboration network. University of South Florida, Henry Ford Hospital, and Oakland University were the most influential institutions. Stroke, Brain Research, and Neural Regeneration Research were the most productive journals. The research in this field was primarily focused on the effects of stem cells on neurogenesis, inflammation, and angiogenesis following ischemic stroke, as well as their therapeutic potential for the disease. In addition, neural stem cells and mesenchymal stem cells are the most commonly utilized stem cells. The topics related to miRNA, extracellular vesicles, exosomes, mesenchymal stem cells, neuroinflammation, and autophagy are current research hotspots. Conclusion: Our bibliometric study provides a novel perspective on the research trends in the field of stem cells and ischemic stroke. The outcome of this study may benefit scientists to identify research hotspots and development directions, thereby advancing the application of stem cell-based therapy for ischemic stroke.

The advantages of multi-level omics research on stem cell-based therapies for ischemic stroke.

Stem cell transplantation is a potential therapeutic strategy for ischemic stroke. However, despite many years of preclinical research, the application of stem cells is still limited to the clinical trial stage. Although stem cell therapy can be highly beneficial in promoting functional recovery, the precise mechanisms of action that are responsible for this effect have yet to be fully elucidated. Omics analysis provides us with a new perspective to investigate the physiological mechanisms and multiple functions of stem cells in ischemic stroke. Transcriptomic, proteomic, and metabolomic analyses have become important tools for discovering biomarkers and analyzing molecular changes under pathological conditions. Omics analysis could help us to identify new pathways mediated by stem cells for the treatment of ischemic stroke via stem cell therapy, thereby facilitating the translation of stem cell therapies into clinical use. In this review, we summarize the pathophysiology of ischemic stroke and discuss recent progress in the development of stem cell therapies for the treatment of ischemic stroke by applying multi-level omics. We also discuss changes in RNAs, proteins, and metabolites in the cerebral tissues and body fluids under stroke conditions and following stem cell treatment, and summarize the regulatory factors that play a key role in stem cell therapy. The exploration of stem cell therapy at the molecular level will facilitate the clinical application of stem cells and provide new treatment possibilities for the complete recovery of neurological function in patients with ischemic stroke.

Pre-clinical efficacy evaluation of human umbilical cord mesenchymal stem cells for ischemic stroke.

This study explored the underlying therapeutic mechanism of human umbilical cord mesenchymal stem cells (hUCMSCs) for ischemic stroke (IS), and determined the optimal administration time windows and dose-effect relationship. The levels of SDF-1α, IL-10, IL-6, TNF-α, BDNF, IL-1β, and VEGF-A factors in serum and brain tissue lysate were measured by ELISA. The pathological status of brain tissues was evaluated by Hematoxylin-Eosin (HE) staining, and apoptosis of nerve cells was detected by tunel. The protein expression of CXCR-4, NeuN, and Nestin in the brain tissues was assessed through immunofluorescence. The balance beam, forelimb muscle strength, and limb placement were tested on MCAO rats at different time points and doses. The infarct area of the rat brain tissues was measured at the end of the experiment. The hUCMSC treatment during the acute phase of MCAO significantly reduced the secretion of IL-6, TNF-α, IL-1β but increased IL-10 in serum, and the levels of SDF-α and BDNF in serum and brain tissues lysate were also increased. The pathological results showed that there were more neurons in the treatment group compared to the model group. Immunofluorescence assays showed that the expression of CXCR4、Nestin、NeuN was relatively higher than that in the model group. The d4 and d7 treatment significantly improves the motor function, promotes the recovery of forelimb muscle strength, increases the forelimb placement rate and reduces the scope of cerebral infarction, but the d14 treatment group has less therapeutic effect compared to the d4 and d7 treatment. The 2×107/kg treatment showed the best therapeutic effect, followed by the 1×107/kg treatment, and the worst is 0.5×107/kg treatment from the test of balance beam, forelimb muscle strength, limb placement and the infarct area of the rat brain tissues. The hUCMSCs can inhibit the infiltration of inflammatory cells in the brain tissue, and promote the repair of brain tissue structure and function. Early intervention by injecting high-dose of hUCMSCs can significantly improve the recovery of neurological/motor function and reduce the size of cerebral infarction in rats.

Paracrine Effects of Mesenchymal Stem Cells in Ischemic Stroke: Opportunities and Challenges.

It is well acknowledged that neuroprotective effects of transplanted mesenchymal stem cells (MSCs) in ischemic stroke are attributed to their paracrine-mediated actions or bystander effects rather than to cell replacement in infarcted areas. This therapeutic plasticity is due to MSCs' ability to secrete a broad range of bioactive molecules including growth factors, trophic factors, cytokines, chemokines, and extracellular vesicles, overall known as the secretome. The secretome derivatives, such as conditioned medium (CM) or purified extracellular vesicles (EVs), exert remarkable advantages over MSC transplantation in stroke treating. Here, in this review, we used published information to provide an overview on the secretome composition of MSCs, underlying mechanisms of therapeutic effects of MSCs, and preclinical studies on MSC-derived products application in stroke. Furthermore, we discussed current advantages and challenges for successful bench-to-bedside translation.

Efficacy and Safety of Intravenous Mesenchymal Stem Cells for Ischemic Stroke.

To test whether autologous modified mesenchymal stem cells (MSCs) improve recovery in patients with chronic major stroke. In this prospective, open-label, randomized controlled trial with blinded outcome evaluation, patients with severe middle cerebral artery territory infarct within 90 days of symptom onset were assigned, in a 2:1 ratio, to receive preconditioned autologous MSC injections (MSC group) or standard treatment alone (control group). The primary outcome was the score on the modified Rankin Scale (mRS) at 3 months. The secondary outcome was to further demonstrate motor recovery. A total of 39 and 15 patients were included in the MSC and control groups, respectively, for the final intention-to-treat analysis. Mean age of patients was 68 (range 28-83) years, and mean interval between stroke onset to randomization was 20.2 (range 5-89) days. Baseline characteristics were not different between groups. There was no significant difference between the groups in the mRS score shift at 3 months (p = 0.732). However, secondary analyses showed significant improvements in lower extremity motor function in the MSC group compared to the control group (change in the leg score of the Motricity Index, p = 0.023), which was notable among patients with low predicted recovery potential. There were no serious treatment-related adverse events. IV application of preconditioned, autologous MSCs with autologous serum was feasible and safe in patients with chronic major stroke. MSC treatment was not associated with improvements in the 3-month mRS score, but we did observe leg motor improvement in detailed functional analyses. This study provides Class III evidence that autologous MSCs do not improve 90-day outcomes in patients with chronic stroke. NCT01716481.

Alogenic Adipose Tissue-derived Mesenchymal Stem Cells in Ischemic Stroke

Alogenic Adipose Tissue-derived Mesenchymal Stem Cells in Ischemic Stroke

Research trends of stem cells in ischemic stroke from 1999 to 2018: A bibliometric analysis

ObjectiveMany studies have evaluated the safety and efficacy of stem cells as therapeutic agents for ischemic stroke. We aimed to quantitatively assess the research trends of stem cell therapy for ischemic stroke. Patients and methodsWe searched the Web of Science Core Collection to identify relevant publications between 1999 and 2018. We used HistCite to summarize the critical information, including yearly records, authors, countries/regions, and institutions. VOSviewer was applied to map the collaborations between studies. Based on the title and abstract of each publication, MeSH terms were obtained using Medical Text Indexer to demonstrate evolutions of topic hotspots. ResultsFrom 1999–2018, there were a total of 3,741 publications exploring the prospect of stem cells in ischemic stroke. Annual publication outputs grew from six records to 366 records. Stroke was the most high-profile journal because of its ranking first on the top productive and co-cited journal lists. The United States of America and China were the two most contributive countries of stem-cell research of ischemic stroke. Researchers were supposed to follow studies from productive institutions because of their consistent and systematic investigations in this field. Neural stem cells and mesenchymal stem cells were the most recognized cells for clinical translation. ConclusionWith the growth of publications concerning the role of stem cells in ischemic stroke treatment, bibliometrics helps researchers to get insights of academic collaborations, research trends, and hot topics in the study field.

Abstract 85: Intravenous Application of Autologous Preconditioned Mesenchymal Stem Cells for Ischemic Stroke: Final Results of a Randomized Controlled Trial

Background: Preclinical studies showed that stroke induces a process of recovery via the activation of MSCs, and culture methods for MSCs using stroke patient’s serum obtained during the acute phase of a stroke could constitute a novel MSC activation method. The present trial was conducted to test whether modified MSCs with autologous serum improve the recovery in patients with chronic stroke. Methods: In this prospective, randomized controlled trial, patients with moderate-to-severe disabling middle cerebral artery territory infarct observed within 90 days of the onset of symptoms were assigned, in a 2:1 ratio, to receive MSC therapy (intervention group) or standard care alone (control group), and followed for 3 months. The primary outcome was the score on the mRS at 3 months of treatment. Results: Totals of 39 and 15 patients completed the follow-up in the intervention and control groups, respectively. The mean interval between stroke onset to randomization was 20.2±17.2 days. The mean age was 63.4±13.9 and median NIHSS score was 11 [IQR, 8-17] in the study population. The baseline characteristics were well balanced in the two groups. The median mRS score at day 90 was 3 [IQR, 3-4] in the intervention group and 4 [IQR, 3-4] in the treatment group (P = 0.879). Proportional odds ratio for good functional outcome (mRS at 3 months of treatment) with the stem cell treatment was 0.65 (95% confidence interval, 0.18-2.44; P = 0.529), after adjusting for age, gender, and initial NIHSS scores. In secondary efficacy endpoint, no significant difference was found in the two groups measured by global Fugl-Meyer assessment. However, Fugl-Meyer score in the lower motor function showed significant improvement in the intervention group (delta between baseline and 90-day, 2.3 vs. 4.7; P<0.01). In terms of secondary safety outcomes, one patient in the control group experienced recurrent stroke, and one each patients of the intervention group had transient allergic reaction and one pneumonia. Conclusions: Among patients with chronic stroke, treatment with autologous preconditioned MSC was feasible but did not improve long-term functional outcome. Further studies are needed to select responders to MSC therapies and to improve efficacy of stem cell therapeutics.

Abstract TP132: The Combination Therapy of Intravenous Mannitol and Hypoxic Preconditioned Stem Cells for Ischemic Stroke

Introduction: Hypoxic preconditioning of stem cells is currently employed as a strategy to prepare stem cells for increased survival and engraftment in the host. Mannitol enhances blood-brain barrier permeabilization and can improves the efficiency of systemically administered stem cells. The aim of this study is to elucidate the neuroprotective effects of combination of intravenous mannitol injection and the preconditioned stem cell transplantation on stroke induced neural injury. Materials and Methods: Human adipose stem cells (hADSCs) and mouse induced neural stem cells (miNSCs) were subjected to hypoxic preconditioning by culture in 2% O 2 . 24 hours after middle cerebral artery occlusion, all experimental animals were injected with mannitol intravenously. Five or ten minutes after mannitol injection, vehicle (PBS) or normal hADSCs or preconditioned hADSCs or normal miNSCs or preconditioned miNSCs were intravenously administered to the stroke animals. Neurobehavior functions and infarction volume were compared among the experimental groups. Immunohistochemistry was also performed to reveal the stem cell migration into the brain and histological changes after stem cell implantation. Results: Mannitol injection 10 minutes before stem cell transplantation more increased cell permeability compared to that of 5 and 15 minutes (p<0.05). Hypoxic preconditioned hADSCs more improved neurobehavioral deficits compared to any other stem cell groups (p<0.001). Immunohistological studies showed that stem cell treatment increased neuronal proliferation and angiogenesis, and decreased inflammatory reaction. The combination therapy of mannitol and hypoxic preconditioned hADSCs showed more increased neuronal proliferation and angiogenesis compared to any other stem cell groups (p<0.01). Conclusion: Based on our data, the combination therapy of mannitol and hypoxic preconditioned stem cells seems to have therapeutic potential for the ischemic stroke. Furthermore, hypoxic preconditioned hADSCs more augmented neuronal proliferation compared to normal hADSCs and preconditioned miNSCs. These findings suggest that hADSCs might be more eligible to hypoxic preconditioning than iNSCs for ischemic stroke.

Multicellular Crosstalk Between Exosomes and the Neurovascular Unit After Cerebral Ischemia. Therapeutic Implications

Restorative strategies after stroke are focused on the remodeling of cerebral endothelial cells and brain parenchymal cells. The latter, i.e., neurons, neural precursor cells and glial cells, synergistically interact with endothelial cells in the ischemic brain, providing a neurovascular unit (NVU) remodeling that can be used as target for stroke therapies. Intercellular communication and signaling within the NVU, the multicellular brain-vessel-blood interface, including its highly selective blood-brain barrier, are fundamental to the central nervous system homeostasis and function. Emerging research designates cell-derived extracellular vesicles and especially the nano-sized exosomes, as a complex mean of cell-to-cell communication, with potential use for clinical applications. Through their richness in active molecules and biological information (e.g., proteins, lipids, genetic material), exosomes contribute to intercellular signaling, a condition particularly required in the central nervous system. Cerebral endothelial cells, perivascular astrocytes, pericytes, microglia and neurons, all part of the NVU, have been shown to release and uptake exosomes. Also, exosomes cross the blood-brain and blood-cerebrospinal fluid barriers, allowing communication between periphery and brain, in normal and disease conditions. As such exosomes might be a powerful diagnostic tool and a promising therapeutic shuttle of natural nanoparticles, but also a means of disease spreading (e.g., immune system modulation, pro-inflammatory action, propagation of neurodegenerative factors). This review highlights the importance of exosomes in mediating the intercellular crosstalk within the NVU and reveals the restorative therapeutic potential of exosomes harvested from multipotent mesenchymal stem cells in ischemic stroke, a frequent neurologic condition lacking an efficient therapy.

Reflection on the governance of clinical stem cell research and applications in China.

Reflection on the governance of clinical stem cell research and applications in China.

Neuroprotective Effects of Stem Cells in Ischemic Stroke

Ischemic stroke, the most common subtype of stroke, has been one of the leading causes of mobility and mortality worldwide. However, it is still lacking of efficient agents. Stem cell therapy, with its vigorous advantages, has attracted researchers around the world. Numerous experimental researches in animal models of stroke have demonstrated the promising efficacy in treating ischemic stroke. The underlying mechanism involved antiapoptosis, anti-inflammation, promotion of angiogenesis and neurogenesis, formation of new neural cells and neuronal circuitry, antioxidation, and blood-brain barrier (BBB) protection. This review would focus on the types and neuroprotective actions of stem cells and its potential mechanisms for ischemic stroke.

Mesenchymal Stem Cells for Ischemic Stroke: Progress and Possibilities.

Stroke is the most common neurological cause of morbidity and mortality in industrialized countries, afflicting 15 million people every year. The numbers are expected to increase, mostly due to aging populations. One in five stroke patients dies, and one in three are left with permanent disabilities. Although some acute phase therapies such as intravenous recombinant tissue plasminogen activator (rt-PA) andendovascular treatment have been shown to improve ischemic stroke outcome, these therapies are available only for a small proportion of patients. The use of stem cells to replace brain cells lost during stroke is a long-term goal, and one which is difficult to achieve given that transplanted cells must integrate and restore neural pathways to regain function of damaged parts of the brain. Over the past decade the use of mesenchymal stromal cells (MSCs) as therapy has emerged as a particularly attractive option. MSCs are a class of multipotent, self-renewing cells that give rise to differentiated progeny when implanted into appropriate tissues. Herein, we present a review of the application of MSCs in ischemic stroke, including the source of MSCs, the route and timing of their delivery into the brain and the endpoints measured. Experimental data of transplantation of MSCs in animal stroke models suggest an improved functional recovery. The transplantation of MSCs influences a wide range of events by modulating the inflammatory environment, stimulating endogenous neurogenesis and angiogenesis and reducing the formation of glial scar, although the precise, underlying mechanism of this phenomenon remains unknown. The results from early clinical trials highlight the need to optimize variables such as cell selection and route of administration in order to translate these results into safe and successful clinical applications.

Intrathecal Autologous Bone Marrow Derived Mesenchymal Stem Cells for Ischemic Stroke: Short Term Safety and Efficacy Study

Background: Preclinical and animal studies provide considerable hope for stem cell therapy in cerebrovascular stroke. This study was designed as a pilot study to explore this provisional data. Autologous bone marrow derived mesenchymal stem cells were chosen due to their proven angiogenic, paracrine and neuroregenerative functions. Subjects and Methods: The present study included 32 patients with ischemic stroke fulfilling the following criteria: Inclusion Criteria: 1. Patients with established stroke in the distribution of the middle cerebral artery territory. 2. Six months at least after the onset of acute ischemic stroke. 3. CT brain at the onset denoting acute ischemic stroke. Exclusion Criteria: 1. Hemorrhagic stroke. 2. Conditions which mimick stroke,e.g., multiple sclerosis, vasculitis, arteriovenous malformations, trauma, tumours. Patients were randomly divided into control group (11 patients) and study group (21 patients) which was further divided according to the time between the onset of the stroke and the beginning of the study into: Group I : onset of the stroke and the beginning of the study :6-12 months( 12 patients: 6 males and 6 females). Group II: onset of stroke and the beginning of the study :13-36 months (9 patients: 5 males and 4 females). Control Group: 11 stroke patients : 6 males and 5 females. Time from onset of stroke to beginning of the study ranged from 6-30 months. Both study and control group were subjected to thorough clinical and laboratory assessment , CT brain, National institutes of Health Stroke Scale (NIHSS) and th Barthel active daily life (ADL) scale at the start of therapy, and at 1,3,6 and 12 months after the start of therapy. Stem Cell Injection: 10 million autologous bone marrow-derived MSCs were injected via lumbar puncture in the study group. Results and Conclusions: Changes in Follow-up Parameters: 1. Changes in NIHSS score: Control group showed non-significant decrease in NIHSS score starting from the 3rd month. On the other hand, study group showed highly significant decrease in NIHSS score starting from 6th month, more in group I. 2. Changes in ADL score: ADL score showed non-significant increase starting from 3rd month in the control group, while it showed a highly significant increase in the study group starting from 6th month, more pronounced in group I. Intrathecal administration of MSCs is safe and enhances regeneration in ischemic stroke patients.