Synergic Effects of Rehabilitation and Intravenous Infusion of Mesenchymal Stem Cells After Stroke in Rats

Highly aligned electroactive ultrafine fibers promote the differentiation of mesenchymal stem cells into Schwann-like cells for nerve regeneration

This study investigates the efficacy of a novel tissue-engineered scaffold for nerve repair and functional reconstruction following injury. Utilizing stable jet electrospinning, we fabricated aligned ultrafine fibers from dopamine and poly(L-lactic acid) (PLLA), further developing a biomimetic, oriented, and electroactive scaffold comprising poly(pyrrole) (PPy), polydopamine (PDA), and PLLA through dual in situ polymerizations. The scaffold demonstrated enhanced cell adhesion and reactive oxygen species (ROS) scavenging capabilities and promoted the differentiation of mesenchymal stem cells (MSCs) into Schwann-like cells, essential for nerve regeneration. In vivo assessments revealed significant peripheral nerve regeneration in 10 mm sciatic nerve defects in rats, with observations made 12 weeks post-transplantation. This included facilitated myelination and increased muscle density on the injured side, leading to improved motor function recovery. Our results suggest that the aligned PPy/PDA/PLLA fibrous scaffold offers a promising approach for promoting the differentiation of MSCs into Schwann-like cells conducive to nerve regeneration and represents a significant advancement in nerve repair technologies. This study provides a foundational basis for future research into tissue-engineered solutions for nerve damage, potentially impacting clinical strategies for nerve reconstruction.

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.

Rehabilitation facilitates functional improvement following intravenous infusion of mesenchymal stem cells in the chronic phase of cerebral ischemia in rats

The primary objective of this study was to investigate the potential facilitating effects of daily rehabilitation for chronic cerebral ischemia following the intravenous infusion of mesenchymal stem cells (MSC) in rats. The middle cerebral artery (MCA) was occluded by intraluminal occlusion using a microfilament (MCAO). Eight weeks after MCAO induction, the rats were used as a chronic cerebral ischemia model. Four experimental groups were studied: Vehicle group (medium only, no cells); Rehab group (vehicle + rehabilitation), MSC group (MSC only); and Combined group (MSC + rehabilitation). Rat MSCs were intravenously infused eight weeks after MCAO induction, and the rats received daily rehabilitation through treadmill exercise for 20 min. Behavioral testing, lesion volume assessment using magnetic resonance imaging (MRI), and histological analysis were performed during the observation period until 16 weeks after MCAO induction. All treated animals showed functional improvement compared with the Vehicle group; however, the therapeutic efficacy was greatest in the Combined group. The combination therapy is associated with enhanced neural plasticity shown with histological analysis and MRI diffusion tensor imaging. These findings provide behavioral evidence for enhanced recovery by combined therapy with rehabilitation and intravenous infusion of MSCs, and may form the basis for the development of clinical protocols in the future.

Synergistic therapeutic effects of intracerebral transplantation of human modified bone marrow-derived stromal cells (SB623) and voluntary exercise with running wheel in a rat model of ischemic stroke

BACKGROUND

Mesenchymal stromal cell (MSC) transplantation therapy is a promising therapy for stroke patients. In parallel, rehabilitation with physical exercise could ameliorate stroke-induced neurological impairment. In this study, we aimed to clarify whether combination therapy of intracerebral transplantation of human modified bone marrow-derived MSCs, SB623 cells, and voluntary exercise with running wheel (RW) could exert synergistic therapeutic effects on a rat model of ischemic stroke.

METHODS

Wistar rats received right transient middle cerebral artery occlusion (MCAO). Voluntary exercise (Ex) groups were trained in a cage with RW from day 7 before MCAO. SB623 cells (4.0 × 105 cells/5 μl) were stereotactically injected into the right striatum at day 1 after MCAO. Behavioral tests were performed at day 1, 7, and 14 after MCAO using the modified Neurological Severity Score (mNSS) and cylinder test. Rats were euthanized at day 15 after MCAO for mRNA level evaluation of ischemic infarct area, endogenous neurogenesis, angiogenesis, and expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF). The rats were randomly assigned to one of the four groups: vehicle, Ex, SB623, and SB623 + Ex groups.

RESULTS

SB623 + Ex group achieved significant neurological recovery in mNSS compared to the vehicle group (p < 0.05). The cerebral infarct area of SB623 + Ex group was significantly decreased compared to those in all other groups (p < 0.05). The number of BrdU/Doublecortin (Dcx) double-positive cells in the subventricular zone (SVZ) and the dentate gyrus (DG), the laminin-positive area in the ischemic boundary zone (IBZ), and the mRNA level of BDNF and VEGF in SB623 + Ex group were significantly increased compared to those in all other groups (p < 0.05).

CONCLUSIONS

This study suggests that combination therapy of intracerebral transplantation SB623 cells and voluntary exercise with RW achieves robust neurological recovery and synergistically promotes endogenous neurogenesis and angiogenesis after cerebral ischemia, possibly through a mechanism involving the up-regulation of BDNF and VEGF.

Nanoparticle and Stem Cell Combination Therapy for the Management of Stroke

Stroke is currently one of the primary causes of morbidity and mortality worldwide. Unfortunately, the available treatments for stroke are still extremely limited. Indeed, stem cell (SC) therapy is a new option for the treatment of stroke that could significantly expand the therapeutic time window of stroke. Some proposed mechanisms for stroke-based SC therapy are the incorporation of SCs into the host brain to replace dead or damaged cells/tissues. Moreover, acute cell delivery can inhibit apoptosis and decrease lesion size, providing immunomudolatory and neuroprotection effects. However, several major SC problems related to SCs such as homing, viability, uncontrolled differentiation, and possible immune response, have limited SC therapy. A combination of SC therapy with nanoparticles (NPs) can be a solution to address these challenges. NPs have received considerable attention in regulating and controlling the behavior of SCs because of their unique physicochemical properties. By reviewing the pathophysiology of stroke and the therapeutic benefits of SCs and NPs, we hypothesize that combined therapy will offer a promising future in the field of stroke management. In this work, we discuss recent literature in SC research combined with NP-based strategies that may have a synergistic outcome after stroke incidence.

Brain hemispheres with right temporal lobe damage swap dominance in early auditory processing of lexical tones

Labor division of the two brain hemispheres refers to the dominant processing of input information on one side of the brain. At an early stage, or a preattentive stage, the right brain hemisphere is shown to dominate the auditory processing of tones, including lexical tones. However, little is known about the influence of brain damage on the labor division of the brain hemispheres for the auditory processing of linguistic tones. Here, we demonstrate swapped dominance of brain hemispheres at the preattentive stage of auditory processing of Chinese lexical tones after a stroke in the right temporal lobe (RTL). In this study, we frequently presented lexical tones to a group of patients with a stroke in the RTL and infrequently varied the tones to create an auditory contrast. The contrast evoked a mismatch negativity response, which indexes auditory processing at the preattentive stage. In the participants with a stroke in the RTL, the mismatch negativity response was lateralized to the left side, in contrast to the right lateralization pattern in the control participants. The swapped dominance of brain hemispheres indicates that the RTL is a core area for early-stage auditory tonal processing. Our study indicates the necessity of rehabilitating tonal processing functions for tonal language speakers who suffer an RTL injury.

Repeated intravenous infusion of mesenchymal stem cells for enhanced functional recovery in a rat model of chronic cerebral ischemia

OBJECTIVE

Stroke is a major cause of long-term disability, and there are few effective treatments that improve function in patients during the chronic phase of stroke. Previous research has shown that single systemic infusion of mesenchymal stem cells (MSCs) improves motor function in acute and chronic cerebral ischemia models in rats. A possible mechanism that could explain such an event includes the enhanced neural connections between cerebral hemispheres that contribute to therapeutic effects. In the present study, repeated infusions (3 times at weekly intervals) of MSCs were administered in a rat model of chronic stroke to determine if multiple dosing facilitated plasticity in neural connections.

METHODS

The authors induced middle cerebral artery occlusion (MCAO) in rats and, 8 weeks thereafter, used them as a chronic stroke model. The rats with MCAO were randomized and intravenously infused with vehicle only (vehicle group); with MSCs at week 8 (single administration: MSC-1 group); or with MSCs at weeks 8, 9, and 10 (3 times, repeated administration: MSC-3 group) via femoral veins. Ischemic lesion volume and behavioral performance were examined. Fifteen weeks after induction of MCAO, the thickness of the corpus callosum (CC) was determined using Nissl staining. Immunohistochemical analysis of the CC was performed using anti-neurofilament antibody. Interhemispheric connections through the CC were assessed ex vivo by diffusion tensor imaging.

RESULTS

Motor recovery was better in the MSC-3 group than in the MSC-1 group. In each group, there was no change in the ischemic volume before and after infusion. However, both thickness and optical density of neurofilament staining in the CC were greater in the MSC-3 group, followed by the MSC-1 group, and then the vehicle group. The increased thickness and optical density of neurofilament in the CC correlated with motor function at 15 weeks following induction of MCAO. Preserved neural tracts that ran through interhemispheric connections via the CC were also more extensive in the MSC-3 group, followed by the MSC-1 group and then the vehicle group, as observed ex vivo using diffusion tensor imaging.

CONCLUSIONS

These results indicate that repeated systemic administration of MSCs over 3 weeks resulted in greater functional improvement as compared to single administration and/or vehicle infusion. In addition, administration of MSCs is associated with promotion of interhemispheric connectivity through the CC in the chronic phase of cerebral infarction.

Can a Scaffold Enriched with Mesenchymal Stem Cells Be a Good Treatment for Spinal Cord Injury?

Spinal cord injury (SCI) is a worldwide highly crippling disease that can lead to the loss of motor and sensory neurons. Among the most promising therapies, there are new techniques of tissue engineering based on stem cells that promote neuronal regeneration. Among the different types of stem cells, mesenchymal stem cells (MSCs) seem the most promising. Indeed, MSCs are able to release trophic factors and to differentiate into the cell types that can be found in the spinal cord. Currently, the most common procedure to insert cells in the lesion site is infusion. However, this causes a low rate of survival and engraftment in the lesion site. For these reasons, tissue engineering is focusing on bioresorbable scaffolds to help the cells to stay in situ. Scaffolds do not only have a passive role but become fundamental for the trophic support of cells and the promotion of neuroregeneration. More and more types of materials are being studied as scaffolds to decrease inflammation and increase the engraftment as well as the survival of the cells. Our review aims to highlight how the use of scaffolds made from biomaterials enriched with MSCs gives positive results in in vivo SCI models as well as the first evidence obtained in clinical trials.

Physical therapy exerts sub-additive and suppressive effects on intracerebral neural stem cell implantation in a rat model of stroke

Intracerebral cell therapy (CT) is emerging as a new therapeutic paradigm for stroke. However, the impact of physical therapy (PT) on implanted cells and their ability to promote recovery remains poorly understood. To address this translational issue, a clinical-grade neural stem cell (NSC) line was implanted into peri-infarct tissue using MRI-defined injection sites, two weeks after stroke. PT in the form of aerobic exercise (AE) was administered 5 × per week post-implantation using a paradigm commonly applied in patients with stroke. A combined AE and CT exerted sub-additive therapeutic effects on sensory neglect, whereas AE suppressed CT effects on motor integration and grip strength. Behavioral testing emerged as a potentially major component for task integration. It is expected that this study will guide and inform the incorporation of PT in the design of clinical trials evaluating intraparenchymal NSCs implantation for stroke.

Intravenous infusion of auto serum-expanded autologous mesenchymal stem cells in chronic brain injury patients: a study protocol for a Phase II trial (Preprint)

Background

Objective

Methods

Results

Conclusions

Trial Registration

International Registered Report Identifier (IRRID)

Enriched Environment and Exercise Enhance Stem Cell Therapy for Stroke, Parkinson’s Disease, and Huntington’s Disease

Stem cells, specifically embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), induced pluripotent stem cells (IPSCs), and neural progenitor stem cells (NSCs), are a possible treatment for stroke, Parkinson’s disease (PD), and Huntington’s disease (HD). Current preclinical data suggest stem cell transplantation is a potential treatment for these chronic conditions that lack effective long-term treatment options. Finding treatments with a wider therapeutic window and harnessing a disease-modifying approach will likely improve clinical outcomes. The overarching concept of stem cell therapy entails the use of immature cells, while key in recapitulating brain development and presents the challenge of young grafted cells forming neural circuitry with the mature host brain cells. To this end, exploring strategies designed to nurture graft-host integration will likely enhance the reconstruction of the elusive neural circuitry. Enriched environment (EE) and exercise facilitate stem cell graft-host reconstruction of neural circuitry. It may involve at least a two-pronged mechanism whereby EE and exercise create a conducive microenvironment in the host brain, allowing the newly transplanted cells to survive, proliferate, and differentiate into neural cells; vice versa, EE and exercise may also train the transplanted immature cells to learn the neurochemical, physiological, and anatomical signals in the brain towards better functional graft-host connectivity.

Combination of Stem Cells and Rehabilitation Therapies for Ischemic Stroke

Stem cell transplantation with rehabilitation therapy presents an effective stroke treatment. Here, we discuss current breakthroughs in stem cell research along with rehabilitation strategies that may have a synergistic outcome when combined together after stroke. Indeed, stem cell transplantation offers a promising new approach and may add to current rehabilitation therapies. By reviewing the pathophysiology of stroke and the mechanisms by which stem cells and rehabilitation attenuate this inflammatory process, we hypothesize that a combined therapy will provide better functional outcomes for patients. Using current preclinical data, we explore the prominent types of stem cells, the existing theories for stem cell repair, rehabilitation treatments inside the brain, rehabilitation modalities outside the brain, and evidence pertaining to the benefits of combined therapy. In this review article, we assess the advantages and disadvantages of using stem cell transplantation with rehabilitation to mitigate the devastating effects of stroke.

The effects of endurance exercise combined with high-temperature head-out water immersion on serum concentration of brain-derived neurotrophic factor in healthy young men

OBJECTIVES

To evaluate acute changes in serum brain-derived neurotrophic factor (BDNF) concentration following combined endurance exercise and heat stress through head-out water immersion (HOI).

SETTING

Observational study with crossover design.

METHODS

Ten healthy young male participants performed HOI at 40 °C (40 °C HOI) or continuous cycling at 60% of maximal oxygen uptake while immersed in 40 °C (40 °C HOI-ex) or 23 °C water (23 °C HOI-ex) for 15 min. Serum BDNF, cortisol and lactate concentrations, and core temperature (T_core) were measured pre, immediately post, and 15 and 30 min post-immersion.

RESULTS

BDNF concentration increased immediately and 15 min after 40 °C HOI-ex, but not after 40 °C or 23 °C HOI-ex. No changes in T_core concentration were observed during 23 °C HOI-ex (Pre; 37.3 °C ± 0.3 °C, Post; 37.8 °C ± 0.2 °C, Post 15; 37.4 °C ± 0.3 °C, Post 30; 37.2 °C ± 0.2 °C). T_core increased significantly post, post 15, and post 30 min of 40 °C HOI (Pre; 37.1 °C ± 0.4 °C, Post; 38.8 °C ± 0.5 °C, Post 15; 37.9 °C ± 0.4 °C, Post 30; 37.9 °C ± 0.2 °C) and 40 °C HOI-ex (Pre; 37.2 °C ± 0.2 °C, Post; 40.2 °C ± 0.7 °C, Post 15; 38.9 °C ± 0.5 °C, Post 30; 38.3 °C ± 0.5 °C). T_core was higher in 40 °C HOI-ex compared with 40 °C HOI and 23 °C HOI-ex immediately post and post 15 min. Plasma lactate and cortisol were significantly higher in 40 °C HOI-ex compared with 40 °C HOI and 23 °C HOI-ex after immersion (p = 0.001).

CONCLUSION

While 15 min HOI alone or thermoneutral exercise do not increase BDNF concentration, both combined may form a time-efficient strategy to acutely elevate BDNF.

Intravenous infusion of mesenchymal stem cells delays disease progression in the SOD1G93A transgenic amyotrophic lateral sclerosis rat model

ALS is a devastating neurodegenerative disease with few curative strategies. Both sporadic and familial ALS display common clinical features that show progressive paralysis. The pathogenesis remains unclear, but disruption of the blood-spinal cord barrier (BSCB) may contribute to the degeneration of motor neurons. Thus, restoration of the disrupted BSCB and neuroprotection for degenerating motor neurons could be therapeutic targets. We tested the hypothesis that an intravenous infusion of MSCs would delay disease progression through the preservation of BSCB function and increased expression of a neurotrophic factor, neurturin, in SOD1G93A ALS rats. When the open-field locomotor function was under 16 on the Basso, Beattie, and Bresnahan (BBB) scoring scale, the rats were randomized into two groups; one received an intravenous infusion of MSCs, while the other received vehicle alone. Locomotor function was recorded using BBB scoring and rotarod testing. Histological analyses, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), were performed. The MSC group exhibited reduced deterioration of locomotor activity compared to the vehicle group, which displayed progressive deterioration of hind limb function. We observed the protection of motor neuron loss and preservation of microvasculature using Evans blue leakage and immunohistochemical analyses in the MSC group. Confocal microscopy revealed infused green fluorescent protein+ (GFP+) MSCs in the spinal cord, and the GFP gene was detected by nested PCR. Neurturin expression levels were significantly higher in the MSC group. Thus, restoration of the BSCB and the protection of motor neurons might be contributing mechanisms to delay disease progression in SOD1G93A ALS rats.

Mesenchymal Stem Cells for Neurological Disorders

Neurological disorders are becoming a growing burden as society ages, and there is a compelling need to address this spiraling problem. Stem cell-based regenerative medicine is becoming an increasingly attractive approach to designing therapies for such disorders. The unique characteristics of mesenchymal stem cells (MSCs) make them among the most sought after cell sources. Researchers have extensively studied the modulatory properties of MSCs and their engineering, labeling, and delivery methods to the brain. The first part of this review provides an overview of studies on the application of MSCs to various neurological diseases, including stroke, traumatic brain injury, spinal cord injury, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and other less frequently studied clinical entities. In the second part, stem cell delivery to the brain is focused. This fundamental but still understudied problem needs to be overcome to apply stem cells to brain diseases successfully. Here the value of cell engineering is also emphasized to facilitate MSC diapedesis, migration, and homing to brain areas affected by the disease to implement precision medicine paradigms into stem cell-based therapies.

Intravenous infusion of auto serum-expanded autologous mesenchymal stem cells in spinal cord injury patients: 13 case series

BACKGROUND

Although spinal cord injury (SCI) is a major cause of disability, current therapeutic options remain limited. Recent progress in cellular therapy with mesenchymal stem cells (MSCs) has provided improved function in animal models of SCI. We investigated the safety and feasibility of intravenous infusion of MSCs for SCI patients and assessed functional status after MSC infusion.

METHODS

In this phase 2 study of intravenous infusion of autologous MSCs cultured in auto-serum, a single infusion of MSCs under Good Manufacturing Practice (GMP) production was delivered in 13 SCI patients. In addition to assessing feasibility and safety, neurological function was assessed using the American Spinal Injury Association Impairment Scale (ASIA), International Standards for Neurological and Functional Classification of Spinal Cord (ISCSCI-92). Ability of daily living was assessed using Spinal Cord Independence Measure (SCIM-III). The study protocol was based on advice provided by the Pharmaceuticals and Medical Devices Agency in Japan. The trial was registered with the Japan Medical Association (JMA-IIA00154).

RESULTS

No serious adverse events were associated with MSC injection. There was neurologic improvement based on ASIA grade in 12 of the 13 patients at six months post-MSC infusion. Five of six patients classified as ASIA A prior to MSC infusion improved to ASIA B (3/6) or ASIA C (2/6), two ASIA B patients improved to ASIA C (1/2) or ASIA D (1/2), five ASIA C patients improved and reached a functional status of ASIA D (5/5). Notably, improvement from ASIA C to ASIA D was observed one day following MSC infusion for all five patients. Assessment of both ISCSCI-92, SCIM-III also demonstrated functional improvements at six months after MSC infusion, compared to the scores prior to MSC infusion in all patients.

CONCLUSION

While we emphasize that this study was unblinded, and does not exclude placebo effects or a contribution of endogenous recovery or observer bias, our observations provide evidence supporting the feasibility, safety and functional improvements of infused MSCs into patients with SCI.

Additive Behavioral Improvement after Combined Cell Therapy and Rehabilitation Despite Long-Term Microglia Presence in Stroke Rats

Microglia are involved in the post-stroke immunomodulation of brain plasticity, repair, and reorganization. Here, we evaluated whether adipose-tissue-derived mesenchymal stem cells (ADMSCs) and/or rehabilitation improve behavioral recovery by modulating long-term perilesional inflammation and creating a recovery-permissive environment in a rat model of ischemic stroke. Methods: A two-way mixed lymphocyte reaction was used to assess the immunomodulatory capacity of ADMSCs in vitro. Two or 7 days after permanent middle cerebral artery occlusion (pMCAO), rats were intravenously administered ADMSCs or vehicle and housed in a standard or enriched environment (EE). Behavioral performance was assessed with a cylinder test, then we performed stereological and ImageJ/Fiji quantifications of ionized calcium-binding adaptor molecule 1 (Iba1) cells and blood–brain barrier (BBB) leakage. Results: Human ADMSCs were immunosuppressive in vitro. The cylinder test showed partial spontaneous behavioral recovery of pMCAO rats, which was further improved by combined ADMSCs and housing in EE on days 21 and 42 (p < 0.05). We detected an ischemia-induced increase in numbers, staining intensity, and branch length of Iba1+ microglia/macrophages as well as BBB leakage in the perilesional cortex. However, these were not different among pMCAO groups. Conclusion: Combined cell therapy and rehabilitation additively improved behavioral outcome despite long-term perilesional microglia presence in stroke rats.

Transplantation of Mesenchymal Stem Cells Improves Amyloid-β Pathology by Modifying Microglial Function and Suppressing Oxidative Stress

Mesenchymal stem cells (MSC) are increasingly being studied as a source of cell therapy for neurodegenerative diseases, and several groups have reported their beneficial effects on Alzheimer’s disease (AD). In this study using AD model mice (APdE9), we found that transplantation of MSC via the tail vein improved spatial memory in the Morris water maze test. Using electron paramagnetic resonance imaging to evaluate the in vivo redox state of the brain, we found that MSC transplantation suppressed oxidative stress in AD model mice. To elucidate how MSC treatment ameliorates oxidative stress, we focused on amyloid-β (Aβ) pathology and microglial function. MSC transplantation reduced Aβ deposition in the cortex and hippocampus. Transplantation of MSC also decreased Iba1-positive area in the cortex and reduced activated ameboid shaped microglia. On the other hand, MSC transplantation accelerated accumulation of microglia around Aβ deposits and prompted microglial Aβ uptake and clearance as shown by higher frequency of Aβ-containing microglia. MSC transplantation also increased CD14-positive microglia in vivo, which play a critical role in Aβ uptake. To confirm the effects of MSC on microglia, we co-cultured the mouse microglial cell line MG6 with MSC. Co-culture with MSC enhanced Aβ uptake by MG6 cells accompanied by upregulation of CD14 expression. Additionally, co-culture of MG6 cells with MSC induced microglial phenotype switching from M1 to M2 and suppressed production of proinflammatory cytokines. These data indicate that MSC treatment has the potential to ameliorate oxidative stress through modification of microglial functions, thereby improving Aβ pathology in AD model mice.

Optimizing Stem Cell Therapy after Ischemic Brain Injury

Stem cells have been used for regenerative and therapeutic purposes in a variety of diseases. In ischemic brain injury, preclinical studies have been promising, but have failed to translate results to clinical trials. We aimed to explore the application of stem cells after ischemic brain injury by focusing on topics such as delivery routes, regeneration efficacy, adverse effects, and in vivo potential optimization. PUBMED and Web of Science were searched for the latest studies examining stem cell therapy applications in ischemic brain injury, particularly after stroke or cardiac arrest, with a focus on studies addressing delivery optimization, stem cell type comparison, or translational aspects. Other studies providing further understanding or potential contributions to ischemic brain injury treatment were also included. Multiple stem cell types have been investigated in ischemic brain injury treatment, with a strong literature base in the treatment of stroke. Studies have suggested that stem cell administration after ischemic brain injury exerts paracrine effects via growth factor release, blood-brain barrier integrity protection, and allows for exosome release for ischemic injury mitigation. To date, limited studies have investigated these therapeutic mechanisms in the setting of cardiac arrest or therapeutic hypothermia. Several delivery modalities are available, each with limitations regarding invasiveness and safety outcomes. Intranasal delivery presents a potentially improved mechanism, and hypoxic conditioning offers a potential stem cell therapy optimization strategy for ischemic brain injury. The use of stem cells to treat ischemic brain injury in clinical trials is in its early phase; however, increasing preclinical evidence suggests that stem cells can contribute to the down-regulation of inflammatory phenotypes and regeneration following injury. The safety and the tolerability profile of stem cells have been confirmed, and their potent therapeutic effects make them powerful therapeutic agents for ischemic brain injury patients.

Regenerative Rehabilitation for Stroke Recovery by Inducing Synergistic Effects of Cell Therapy and Neurorehabilitation on Motor Function: A Narrative Review of Pre-Clinical Studies

Neurological diseases severely affect the quality of life of patients. Although existing treatments including rehabilitative therapy aim to facilitate the recovery of motor function, achieving complete recovery remains a challenge. In recent years, regenerative therapy has been considered as a potential candidate that could yield complete functional recovery. However, to achieve desirable results, integration of transplanted cells into neural networks and generation of appropriate microenvironments are essential. Furthermore, considering the nascent state of research in this area, we must understand certain aspects about regenerative therapy, including specific effects, nature of interaction when administered in combination with rehabilitative therapy (regenerative rehabilitation), and optimal conditions. Herein, we review the current status of research in the field of regenerative therapy, discuss the findings that could hold the key to resolving the challenges associated with regenerative rehabilitation, and outline the challenges to be addressed with future studies. The current state of research emphasizes the importance of determining the independent effect of regenerative and rehabilitative therapies before exploring their combined effects. Furthermore, the current review highlights the progression in the treatment perspective from a state of compensation of lost function to that of a possibility of complete functional recovery.

A Comparison of Intracerebral Transplantation of RMNE6 Cells and MSCs on Ischemic Stroke Models

Background

Cell therapy using stem cells is promising for stroke patients; however, stem cell therapy faces many problems. RMNE6 cells, a new stem cell line, are superior to other stem cell lines. Mesenchymal stem cells (MSCs) appear to be a promising candidate for stroke patients. In the current study, we determined the therapeutic effects of RMNE6 cells on a middle cerebral artery occlusion (MCAO) model of rats and identified the differences between RMNE6 cells and MSCs with respect to therapeutic effects.

Material and Methods

RMNE6 and Enhanced green fluorescent protein (EGFP)-labeled MSCs were transplanted into the ischemic brains of MCAO rats. The behavior of rats was examined using the rotarod test with neuroradiologic assessment using magnetic resonance imaging (MRI). Four weeks after cell transplantation, the rats were investigated by immunofluorescence staining to explore the fates of the graft cells.

Result

After transplantation, RMNE6 cells and MSCs survived and migrated toward the injured area without differentiation. There was tumorigenesis in the brains transplanted with RMNE6 cells. Cell transplantation had no effects on the size of the ischemic volume. The behavior of the model animals showed no significant improvement.

Conclusion

MSCs are still the preferred cells for cell replacement in stroke therapy, while RMNE6 cells need to be modified.

Prevention of neointimal hyperplasia induced by an endovascular stent via intravenous infusion of mesenchymal stem cells

OBJECTIVE

In-stent restenosis after percutaneous transluminal angioplasty and stenting (PTAS) due to neointimal hyperplasia is a potential cause of clinical complications, including repeated revascularization and ischemic events. Neointimal hyperplasia induced by an inflammatory response to the stent strut may be a possible mechanism of in-stent restenosis. Intravenous infusion of bone marrow-derived mesenchymal stem cells (MSCs) has been reported to show therapeutic efficacy for cerebral stroke, presumably by an antiinflammatory effect. This study aimed to determine whether MSCs can reduce or prevent neointimal hyperplasia induced by an endovascular stent.

METHODS

In this study, two types of bare metal stents were deployed using a porcine (mini-pig) model. One stent was implanted in the common carotid artery (CCA), which is considered quite similar to the human CCA, and the other was inserted in the superficial cervical artery (SCA), which is similar in size to the human middle cerebral artery. Angiographic images, intravascular ultrasound (IVUS) imaging, and microscopic images were used for analysis.

RESULTS

Angiographic images and IVUS studies revealed that intravenous infusion of MSCs immediately after deployment of stents prevented in-stent stenosis of the CCA and SCA. Histological analysis also confirmed that inflammatory responses around the stent struts were reduced in both the stented CCA and SCA in the mini-pig.

CONCLUSIONS

Intravenous infusion of MSCs inhibited the inflammatory reaction to an implanted stent strut, and prevented progressive neointimal hyperplasia in the stented CCA and SCA in a porcine model. Thus, MSC treatment could attenuate the recurrence of cerebral ischemic events after stenting.

Intravenous infusion of mesenchymal stem cells promotes functional recovery in a rat model of chronic cerebral infarction

OBJECTIVE

Intravenous infusion of mesenchymal stem cells (MSCs) derived from adult bone marrow improves behavioral function in rat models of cerebral infarction. Although clinical studies are ongoing, most studies have focused on the acute or subacute phase of stroke. In the present study, MSCs derived from bone marrow of rats were intravenously infused 8 weeks after the induction of a middle cerebral artery occlusion (MCAO) to investigate whether delayed systemic injection of MSCs improves functional outcome in the chronic phase of stroke in rats.

METHODS

Eight weeks after induction of the MCAO, the rats were randomized and intravenously infused with either MSCs or vehicle. Ischemic volume and behavioral performance were examined. Blood-brain barrier (BBB) integrity was assessed by quantifying the leakage of Evans blue into the brain parenchyma after intravenous infusion. Immunohistochemical analysis was also performed to evaluate the stability of the BBB.

RESULTS

Motor recovery was better in the MSC-treated group than in the vehicle-treated group, with rapid improvement (evident at 1 week post-infusion). In MSC-treated rats, reduced BBB leakage and increased microvasculature/repair and neovascularization were observed.

CONCLUSIONS

These results indicate that the systemic infusion of MSCs results in functional improvement, which is associated with structural changes in the chronic phase of cerebral infarction, including in the stabilization of the BBB.

Intravenous infusion of mesenchymal stem cells for protection against brainstem infarction in a persistent basilar artery occlusion model in the adult rat

OBJECTIVE

Morbidity and mortality in patients with posterior circulation stroke remains an issue despite advances in acute stroke therapies. The intravenous infusion of mesenchymal stem cells (MSCs) elicits therapeutic efficacy in experimental supratentorial stroke models. However, since there are few reliable animal models of ischemia in the posterior circulation, the therapeutic approach with intravenous MSC infusion has not been tested. The objective of this study was to test the hypothesis that intravenously infused MSCs provide functional recovery in a newly developed model of brainstem infarction in rats.

METHODS

Basilar artery (BA) occlusion (BAO) was established in rats by selectively ligating 4 points of the proximal BA with 10-0 nylon monofilament suture. The intravenous infusion of MSCs was performed 1 day after BAO induction. MRI and histological examinations were performed to assess ischemic lesion volume, while multiple behavioral tests were performed to evaluate functional recovery.

RESULTS

The MSC-treated group exhibited a greater reduction in ischemic lesion volume, while behavioral testing indicated that the MSC-infused group had greater improvement than the vehicle group 28 days after the MSC infusion. Accumulated infused MSCs were observed in the ischemic brainstem lesion.

CONCLUSIONS

Infused MSCs may provide neuroprotection to facilitate functional outcomes and reduce ischemic lesion volume as evaluated in a newly developed rat model of persistent BAO.

Combined Adipose Tissue-Derived Mesenchymal Stem Cell Therapy and Rehabilitation in Experimental Stroke

Background/Objective: Stroke is a leading global cause of adult disability. As the population ages as well as suffers co-morbidities, it is expected that the stroke burden will increase further. There are no established safe and effective restorative treatments to facilitate a good functional outcome in stroke patients. Cell-based therapies, which have a wide therapeutic window, might benefit a large percentage of patients, especially if combined with different restorative strategies. In this study, we tested whether the therapeutic effect of human adipose tissue-derived mesenchymal stem cells (ADMSCs) could be further enhanced by rehabilitation in an experimental model of stroke. Methods: Focal cerebral ischemia was induced in adult male Sprague Dawley rats by permanently occluding the distal middle cerebral artery (MCAO). After the intravenous infusion of vehicle (n = 46) or ADMSCs (2 × 10⁶) either at 2 (n = 37) or 7 (n = 7) days after the operation, half of the animals were housed in an enriched environment mimicking rehabilitation. Subsequently, their behavioral recovery was assessed by a neurological score, and performance in the cylinder and sticky label tests during a 42-day behavioral follow-up. At the end of the follow-up, rats were perfused for histology to assess the extent of angiogenesis (RECA-1), gliosis (GFAP), and glial scar formation. Results: No adverse effects were observed during the follow-up. Combined ADMSC therapy and rehabilitation improved forelimb use in the cylinder test in comparison to MCAO controls on post-operative days 21 and 42 (P < 0.01). In the sticky label test, ADMSCs and rehabilitation alone or together, significantly decreased the removal time as compared to MCAO controls on post-operative days 21 and 42. An early initiation of combined therapy seemed to be more effective. Infarct size, measured by MRI on post-operative days 1 and 43, did not differ between the experimental groups. Stereological counting revealed an ischemia-induced increase both in the density of blood vessels and the numbers of glial cells in the perilesional cortex, but there were no differences among MCAO groups. Glial scar volume was also similar in MCAO groups. Conclusion: Early delivery of ADMSCs and combined rehabilitation enhanced behavioral recovery in an experimental stroke model. The mechanisms underlying these treatment effects remain unknown.

Mesenchymal stem cell transplantation and aerobic exercise for Parkinson's disease: therapeutic assets beyond the motor domain

Parkinson's disease (PD) is a very common neurodegenerative condition in which both motor and nonmotor deficits evolve throughout the course of the disease. Normally characterized as a movement disorder, PD has been broadly studied from a motor perspective. However, mild to moderate cognitive deficits began to appear in the early phases of the disease, even before motor disturbances actually manifest, and continue to progress relentlessly. These nonmotor manifestations are also a source of detriment to the patients' already strained functionality and quality of life, and pose a therapeutic challenge seeing that replacing therapies have had conflicting results. Considering that the currently approved therapies can hardly be considered curative, efforts to find therapeutic approaches with an actual disease-modifying quality and capable of addressing not only motor but also cognitive dysfunctions are clearly needed. Among possible alternatives with such attribute, mesenchymal stem cell transplantation and exercise are worth highlighting given their common neuroprotective, neuroplastic, and immunomodulatory properties. In this paper, we will summarize the existent literature on the topic, focusing on the mechanisms of action through which these two approaches might beget therapeutic benefits for PD beyond the commonly assessed motor dysfunctions, alluding, at the same time, toward a potential synergic association of both therapies as an optimized approach for PD.

Functional recovery after the systemic administration of mesenchymal stem cells in a rat model of neonatal hypoxia-ischemia

The authors intravenously infused mesenchymal stem cells (MSCs) into a rat model of neonatal hypoxia-ischemia and found improvements in functional outcome, increased brain volume, and enhanced synaptogenesis. The results of this animal study suggest that the intravenous administration of MSCs should be further explored as a potential treatment for patients suffering from cerebral palsy after hypoxic-ischemic encephalopathy.

RLIPostC protects against cerebral ischemia through improved synaptogenesis in rats

OBJECTIVE

Remote limb ischemic post-conditioning (RLIPostC) has been shown to be neuroprotective in cerebral ischemia, whereas the effect of RLIPostC on synaptogenesis remains elusive. In the present study, we investigated the effects of RLIPostC on synaptogenesis in an experimental stroke rat model.

METHODS

Sprague-Dawley rats were subjected to left middle cerebral artery occlusion (MCAO) and were randomly divided into a control group, an RLIPostC group and a sham group. The RLIPostC group received three cycles of RLIPostC treatment immediately after reperfusion (ten minutes ischemia and ten minutes reperfusion in bilateral femoral artery). The neurological function was assessed by neurological deficit scores and the foot fault test at days 7 and 14 after MCAO. At day 14 after MCAO, the infarct volume and oedema were determined by cresyl violet (CV) staining and by measuring brain water content, respectively. Synaptogenesis was evaluated by western blotting and immunofluorescence staining.

RESULTS

Our results showed that RLIPostC treatment significantly promoted the recovery of behavioural function, reduced infarct volume and brain oedema, and increased the expressions of SYN1, PSD95 and GAP43.

CONCLUSIONS

These results confirmed that RLIPostC treatment for cerebral ischemia was safe and effective. A possible molecular mechanism of the beneficial effects of RLIPostC treatment may be the promotion of synaptogenesis.

Rat Cranial Bone-Derived Mesenchymal Stem Cell Transplantation Promotes Functional Recovery in Ischemic Stroke Model Rats

The functional disorders caused by central nervous system (CNS) diseases, such as ischemic stroke, are clinically incurable and current treatments have limited effects. Previous studies suggested that cell-based therapy using mesenchymal stem cells (MSCs) exerts therapeutic effects for ischemic stroke. In addition, the characteristics of MSCs may depend on their sources. Among the derived tissues of MSCs, we have focused on cranial bones originating from the neural crest. We previously demonstrated that the neurogenic potential of human cranial bone-derived MSCs (cMSCs) was higher than that of human iliac bone-derived MSCs. Therefore, we presumed that cMSCs have a higher therapeutic potential for CNS diseases. However, the therapeutic effects of cMSCs have not yet been elucidated in detail. In the present study, we aimed to demonstrate the therapeutic effects of transplantation with rat cranial bone-derived MSCs (rcMSCs) in ischemic stroke model rats. The mRNA expression of brain-derived neurotrophic factor and nerve growth factor was significantly stronger in rcMSCs than in rat bone marrow-derived MSCs (rbMSCs). Ischemic stroke model rats in the rcMSC transplantation group showed better functional recovery than those in the no transplantation and rbMSC transplantation groups. Furthermore, in the in vitro study, the conditioned medium of rcMSCs significantly suppressed the death of neuroblastoma × glioma hybrid cells (NG108-15) exposed to oxidative and inflammatory stresses. These results suggest that cMSCs have potential as a candidate cell-based therapy for CNS diseases.

Preservation of interhemispheric cortical connections through corpus callosum following intravenous infusion of mesenchymal stem cells in a rat model of cerebral infarction

Systemic administration of mesenchymal stem cells (MSCs) following cerebral infarction exerts functional improvements. Previous research has suggested potential therapeutic mechanisms that promote neuroprotection and synaptogenesis. These include secretion of neurotrophic factors, remodeling of neural circuits, restoration of the blood brain barrier, reduction of inflammatory infiltration and demyelination, and elevation of trophic factors. In addition to these mechanisms, we hypothesized that restored interhemispheric bilateral motor cortex connectivity might be an additional mechanism of functional recovery. In the present study, we have shown, with both MRI diffusion tensor imaging (DTI) and neuroanatomical tracing techniques using an adeno-associated virus (AAV) expressing GFP, that there was anatomical restoration of cortical interhemispheric connections through the corpus callosum after intravenous infusion of MSCs in a rat middle cerebral artery occlusion (MCAO) stroke model. Moreover, the degree of connectivity was greater in the MSC-treated group than in the vehicle-infused group. In accordance, both the thickness of corpus callosum and synaptic puncta in the contralateral (non-infarcted) motor cortex connected to the corpus callosum were greater in the MSC-treated group than in the vehicle group. Together, these results suggest that distinct preservation of interhemispheric cortical connections through corpus callosum was promoted by intravenous infusion of MSCs. This anatomical preservation of the motor cortex in the contralateral hemisphere may contribute to functional improvements following MSC therapy for cerebral stroke.

Mesenchymal stem cell transplantation as an effective treatment strategy for ischemic stroke in Asia: a meta-analysis of controlled trials

Objective

The aim of this study was to evaluate the efficacy and safety of the mesenchymal stem cell (MSC) therapy in patients with ischemic stroke (IS).

Materials and methods

Clinical trials involved in this research were searched from PubMed, Web of Science, Cochrane Library, Embase, Wanfang and CNKI database. Therapeutic effects of MSC therapy were assessed according to National Institutes of Health Stroke Scale (NIHSS), Barthel index (BI), Fugl-Meyer Assessment (FMA) and Functional Independence Measure (FIM), and its safety was evaluated based on adverse events.

Results

This research covered 23 trials including 1,279 IS patients. Based on our analysis, the overall condition of IS patients significantly improved after MSC therapy, indicated by decreased NIHSS and increased BI, FMA and FIM scores. Our analysis also showed that the treatment effects in the MSC transplantation group were superior to those in the control group (routine medication therapy) with statistical significance for NIHSS (1 month after therapy: odds ratio [OR]=-1.92, CI=-3.49 to -0.34, P=0.02; 3 months after therapy: OR=-2.65, CI=-3.40 to -1.90, P<0.00001), BI (1 month after therapy: OR=0.99, CI=0.19-1.79, P=0.02; 6 months after therapy: OR=10.10, CI=3.07-17.14, P=0.005), FMA (3 months after therapy: OR=10.20, CI=3.70-16.70, P=0.002; 6 months after therapy: OR=10.82, CI=6.45-15.18, P<0.00001) and FIM (1 month after therapy: OR=15.61, CI=-0.02 to 31.24, P=0.05; 6 months after therapy: OR=16.56, CI=9.06-24.06, P<0.0001). No serious adverse events were reported during MSC therapy.

Conclusion

MSC therapy is safe and effective in treating IS by improving the neurological deficits, motor function and daily life quality of patients.

Intravenous infusion of mesenchymal stem cells reduces epileptogenesis in a rat model of status epilepticus

OBJECTIVE

Status epilepticus (SE) causes neuronal cell death, aberrant mossy fiber sprouting (MFS), and cognitive deteriorations. The present study tested the hypothesis that systemically infused mesenchymal stem cells (MSCs) reduce epileptogenesis by inhibiting neuronal cell death and suppressing aberrant MFS, leading to cognitive function preservation in a rat model of epilepsy.

METHODS

SE was induced using the lithium-pilocarpine injection model. The seizure frequency was scored using a video-monitoring system and the Morris water maze test was carried out to evaluate cognitive function. Comparisons were made between MSCs- and vehicle-infused rats. Immunohistochemical staining was performed to detect Green fluorescent protein (GFP)⁺ MSCs and to quantify the number of GAD67⁺ and NeuN⁺ neurons in the hippocampus. Manganese-enhanced magnetic resonance imaging (MEMRI) and Timm staining were also performed to assess the MFS.

RESULTS

MSC infusion inhibited epileptogenesis and preserved cognitive function after SE. The infused GFP⁺ MSCs were accumulated in the hippocampus and were associated with the preservation of GAD67⁺ and NeuN⁺ hippocampal neurons. Furthermore, the MSC infusion suppressed the aberrant MFS in the hippocampus as evidenced by MEMRI and Timm staining.

CONCLUSIONS

This study demonstrated that the intravenous infusion of MSCs mitigated epileptogenesis, thus advancing MSCs as an effective approach for epilepsy in clinical practice.

Intravenous Infusion of Bone Marrow-Derived Mesenchymal Stem Cells Reduces Erectile Dysfunction Following Cavernous Nerve Injury in Rats

Introduction

Intravenous preload (delivered before cavernous nerve [CN] injury) of bone marrow–derived mesenchymal stem cells (MSCs) can prevent or decrease postoperative erectile dysfunction (J Sex Med 2015;12:1713–1721). In the present study, the potential therapeutic effects of intravenously administered MSCs on postoperative erectile dysfunction were evaluated in a rat model of CN injury.

Methods

Male Sprague-Dawley rats were randomized into 2 groups after electric CN injury. Intravenous infusion of bone marrow–derived MSCs (1.0 × 10⁶ cells in Dulbecco's modified Eagle's medium 1 mL) or vehicle (Dulbecco's modified Eagle's medium 1 mL) was performed 3 hours after electrocautery-induced CN injury.

Main Outcome Measures

To assess erectile function, we measured intracavernous pressure at 4 weeks after MSC or vehicle infusion. Histologic examinations were performed to investigate neuronal innervation and inhibition of smooth muscle atrophy. Green fluorescent protein–positive bone marrow–derived MSCs were used for cell tracking. To investigate mRNA expression levels of neurotrophins in the major pelvic ganglia (MPGs), quantitative real-time polymerase chain reaction was performed.

Results

The decrease of intracavernous pressure corrected for arterial pressure and area under the curve of intracavernous pressure in the bone marrow–derived MSC group was significantly lower than that in the vehicle group at 4 weeks after infusion (P < .05). Retrograde neuronal tracing indicated that the MSC group had a larger number of FluoroGold-positive neurons in the MPGs compared with the vehicle group. The ratio of smooth muscle to collagen in the MSC group was significantly higher than in the vehicle group. Green fluorescent protein–positive bone marrow–derived MSCs were detected in the MPGs and injured CNs using confocal microscopy, indicating homing of cells to the MPGs and injured CNs. Brain-derived neurotrophic factor and glial cell-derived neurotrophic factor expression levels in the MPGs were significantly higher in the MSC group than in the vehicle group (P < .01).

Conclusion

Intravenous infusion of bone marrow–derived MSCs after CN injury might have therapeutic efficacy in experimental erectile dysfunction.

Matsuda Y, Sasaki M, Kataoka-Sasaki Y, et al. Intravenous Infusion of Bone Marrow–Derived Mesenchymal Stem Cells Reduces Erectile Dysfunction Following Cavernous Nerve Injury in Rats. Sex Med 2018;6:49–57.

Cell Therapy in Stroke-Cautious Steps Towards a Clinical Treatment

In the future, stroke patients may receive stem cell therapy as this has the potential to restore lost functions. However, the development of clinically deliverable therapy has been slower and more challenging than expected. Despite recommendations by STAIR and STEPS consortiums, there remain flaws in experimental studies such as lack of animals with comorbidities, inconsistent approaches to experimental design, and concurrent rehabilitation that might lead to a bias towards positive results. Clinical studies have typically been small, lacking control groups as well as often without clear biological hypotheses to guide patient selection. Furthermore, they have used a wide range of cell types, doses, and delivery methods, and outcome measures. Although some ongoing and recent trial programs offer hints that these obstacles are now being tackled, the Horizon2020 funded RESSTORE trial will be given as an example of inconsistent regulatory requirements and challenges in harmonized cell production, logistic, and clinical criteria in an international multicenter study. The PISCES trials highlight the complex issues around intracerebral cell transplantation. Therefore, a better understanding of translational challenges is expected to pave the way to more successful help for stroke patients.

Stem cell therapy for abrogating stroke-induced neuroinflammation and relevant secondary cell death mechanisms

Ischemic stroke is a leading cause of death worldwide. A key secondary cell death mechanism mediating neurological damage following the initial episode of ischemic stroke is the upregulation of endogenous neuroinflammatory processes to levels that destroy hypoxic tissue local to the area of insult, induce apoptosis, and initiate a feedback loop of inflammatory cascades that can expand the region of damage. Stem cell therapy has emerged as an experimental treatment for stroke, and accumulating evidence supports the therapeutic efficacy of stem cells to abrogate stroke-induced inflammation. In this review, we investigate clinically relevant stem cell types, such as hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs), very small embryonic-like stem cells (VSELs), neural stem cells (NSCs), extraembryonic stem cells, adipose tissue-derived stem cells, breast milk-derived stem cells, menstrual blood-derived stem cells, dental tissue-derived stem cells, induced pluripotent stem cells (iPSCs), teratocarcinoma-derived Ntera2/D1 neuron-like cells (NT2N), c-mycER(TAM) modified NSCs (CTX0E03), and notch-transfected mesenchymal stromal cells (SB623), comparing their potential efficacy to sequester stroke-induced neuroinflammation and their feasibility as translational clinical cell sources. To this end, we highlight that MSCs, with a proven track record of safety and efficacy as a transplantable cell for hematologic diseases, stand as an attractive cell type that confers superior anti-inflammatory effects in stroke both in vitro and in vivo. That stem cells can mount a robust anti-inflammatory action against stroke complements the regenerative processes of cell replacement and neurotrophic factor secretion conventionally ascribed to cell-based therapy in neurological disorders.

Intravenous infusion of mesenchymal stem cells inhibits intracranial hemorrhage after recombinant tissue plasminogen activator therapy for transient middle cerebral artery occlusion in rats

OBJECTIVE Reperfusion therapy with intravenous recombinant tissue plasminogen activator (rtPA) is the standard of care for acute ischemic stroke. However, hemorrhagic complications can result. Intravenous infusion of mesenchymal stem cells (MSCs) reduces stroke volume and improves behavioral function in experimental stroke models. One suggested therapeutic mechanism is inhibition of vascular endothelial dysfunction. The objective of this study was to determine whether MSCs suppress hemorrhagic events after rtPA therapy in the acute phase of transient middle cerebral artery occlusion (tMCAO) in rats. METHODS After induction of tMCAO, 4 groups were studied: 1) normal saline [NS]+vehicle, 2) rtPA+vehicle, 3) NS+MSCs, and 4) rtPA+MSCs. The incidence rate of intracerebral hemorrhage, both hemorrhagic and ischemic volume, and behavioral performance were examined. Matrix metalloproteinase-9 (MMP-9) levels in the brain were assessed with zymography. Quantitative analysis of regional cerebral blood flow (rCBF) was performed to assess hemodynamic change in the ischemic lesion. RESULTS The MSC-treated groups (Groups 3 and 4) experienced a greater reduction in the incidence rate of intracerebral hemorrhage and hemorrhagic volume 1 day after tMCAO even if rtPA was received. The application of rtPA enhanced activation of MMP-9, but MSCs inhibited MMP-9 activation. Behavioral testing indicated that both MSC-infused groups had greater improvement than non-MSC groups had, but rtPA+MSCs provided greater improvement than MSCs alone. The rCBF ratio of rtPA groups (Groups 2 and 4) was similar at 2 hours after reperfusion of tMCAO, but both were greater than that in non-rtPA groups. CONCLUSIONS Infused MSCs may inhibit endothelial dysfunction to suppress hemorrhagic events and facilitate functional outcome. Combined therapy of infused MSCs after rtPA therapy facilitated early behavioral recovery.