Intravenous administration of human adipose-derived stem cells ameliorates motor and cognitive function for intracerebral hemorrhage mouse model

An in vitro culture platform to study the extracellular matrix remodeling potential of human mesenchymal stem cells

The ability of mesenchymal stem cells (MSCs) to synthesize and degrade extracellular matrix (ECM) is important for MSC-based therapies. However, the therapeutic effects associated with ECM remodeling in cultured MSCs have been limited by the lack of a method to assess the ability of cultured cells to degrade ECM in vitro. Here, we describe a simple in vitro culture platform for studying the ECM remodeling potential of cultured MSCs using a high-density collagen (CL) surface. Cells on the CL surface have remarkable ability to degrade collagen fibrils by secreting matrix metalloproteinase (MMP); to study this, the marker collagen hybridizing peptide (CHP) was used. Confirming the ECM remodeling potential of MSCs with different population doublings (PDs), young and healthy γ-H2AX-negative cells, a marker of DNA damage and senescence, showed more extensive collagen degradation on the CL surface, whereas damaged cells of γ-H2AX-positive cells showed no collagen degradation. The frequency of γ-H2AX-/CHP + cells at PD = 0 was 49%, which was 4.9-fold higher than that at PD=13.07, whereas the frequency of γ-H2AX+/CHP- at PD=13.07 was 50%, which was 6.4-folds higher than that at PD=0. Further experimentation examining the in vitro priming effect of MSCs with the pro-inflammatory cytokine interferon-γ treatment showed increased frequency of cells with ECM remodeling potential with higher MMP secretion. Thus, this culture surface can be used for studying the ECM remodeling capacity of ex vivo-expanded MSCs in vitro and may serve as a platform for prediction in vivo ECM remodeling effect. STATEMENT OF SIGNIFICANCE: The extracellular matrix (ECM) remodeling potential of cultured mesenchymal stem cells (MSCs) is important for assessing the effectiveness of MSC-based therapy. However, methods to assess the ability of cultured cells to degrade ECM in vitro are still lacking. Here, we developed a simple in vitro culture platform to study the ECM remodeling potential of cultured MSCs using high-density collagen surfaces. This platform was used to evaluate the ECM remodeling potential of long-term ex vivo-expanded MSCs in vitro.

HDAC inhibitor attenuates rat traumatic brain injury induced neurological impairments

Oxidative stress plays an important role in the secondary neuronal damage after traumatic brain injury (TBI). Inhibition of histone deacetylases (HDACs) has been shown to reduce reactive oxygen species (ROS) production and NADPH oxidases (Nox) transcription. Vorinostat is an HDAC inhibitor. This study investigated the influence of vorinostat on neurological impairments in a rat model of TBI induced by lateral fluid percussion injury (LFPI). Different concentrations of vorinostat (5, 25, and 50 mg/kg) were administered via intraperitoneal injection. Neurological deficits were evaluated by modified neurological severity scoring (mNSS). Evans blue extravasation was performed to assess blood-brain barrier (BBB) permeability. Morris water maze assay was performed to evaluate cognitive impairments. Protein levels were evaluated through ELISA and Western blot. Vorinostat was found to attenuate TBI induced brain edema and BBB permeability in rats. Vorinostat also alleviated TBI-induced neurological impairments and anxiety-like behavior in rats. Vorinostat attenuated TBI induced apoptosis and oxidative stresses in ipsilateral injury cortical tissue. Vorinostat inhibited HDAC1, HDAC3, and Nox4 while activated AMPK signaling in ipsilateral injury cortical tissue. In conclusion, administration of vorinostat alleviates the secondary damage of TBI in rat model. The oxidative stress in the ipsilateral injury cortical tissues is decreased by the inhibition of Nox4 expression and the activation of AMPK.

Transplantation of Human Brain-Derived Ischemia-Induced Multipotent Stem Cells Ameliorates Neurological Dysfunction in Mice After Stroke

We recently demonstrated that injury/ischemia-induced multipotent stem cells (iSCs) develop within post-stroke human brains. Because iSCs are stem cells induced under pathological conditions, such as ischemic stroke, the use of human brain-derived iSCs (h-iSCs) may represent a novel therapy for stroke patients. We performed a preclinical study by transplanting h-iSCs transcranially into post-stroke mouse brains 6 weeks after middle cerebral artery occlusion (MCAO). Compared with PBS-treated controls, h-iSC transplantation significantly improved neurological function. To identify the underlying mechanism, green fluorescent protein (GFP)-labeled h-iSCs were transplanted into post-stroke mouse brains. Immunohistochemistry revealed that GFP+ h-iSCs survived around the ischemic areas and some differentiated into mature neuronal cells. To determine the effect on endogenous neural stem/progenitor cells (NSPCs) by h-iSC transplantation, mCherry-labeled h-iSCs were administered to Nestin-GFP transgenic mice which were subjected to MCAO. As a result, many GFP+ NSPCs were observed around the injured sites compared with controls, indicating that mCherry+ h-iSCs activate GFP+ endogenous NSPCs. In support of these findings, coculture studies revealed that the presence of h-iSCs promotes the proliferation of endogenous NSPCs and increases neurogenesis. In addition, coculture experiments indicated neuronal network formation between h-iSC- and NSPC-derived neurons. These results suggest that h-iSCs exert positive effects on neural regeneration through not only neural replacement by grafted cells but also neurogenesis by activated endogenous NSPCs. Thus, h-iSCs have the potential to be a novel source of cell therapy for stroke patients.

Overexpression of NT3P75-2 gene modified bone marrow mesenchymal stem cells supernatant promotes neurological function recovery in ICH rats

Intracerebral hemorrhage (ICH) is an acute cerebrovascular disease with high mortality and long-term disability rates. Stem cell transplantation and neurotrophic factor therapy have shown great potential in ICH. It has been established that mutated NT3 (NT3P75 - 2) can enhance the positive biological functions of NT3 by decreasing its affinity to the P75-2 receptor. The present study aimed to explore whether NT3P75-2 could further improve neurological recovery after ICH. First, we constructed three stable BMSC cell lines (GFP, GFP-NT3 overexpressed and GFP-NT3P75 - 2 overexpressed) by lentivirus infection. Next, rats were injected with fresh supernatants of these three cell lines on days 1 (24 h) and 3 (72 h) post-ICH induction. Behavioral evaluations were conducted to assess the neurological recovery of ICH rats. We further evaluated changes in microglia activation, neuron survival and proliferation of neural stem cells. Compared with the GFP group and the GFP-NT3 group, animals in the GFP-NT3P75 - 2 group exhibited better motor function improvements and milder neuroinflammation response. Meanwhile, overexpression of NT3P75 - 2 significantly decreased neuronal apoptosis and increased number of SOX2 - positive cells. Taken together, our study demonstrated that early administration of NT3P75 - 2 enriched BMMSC supernatants significantly enhanced neuro-functional recovery after ICH by regulating neuroinflammation response, neuronal survival and increasing neural stem cell number, providing a new therapeutic strategy and direction for early treatment of ICH.

Stem Cell Therapies for Intracerebral Hemorrhage: Review of Preclinical and Clinical Studies

Despite recent developments in the treatments for ischemic stroke, such as tissue plasminogen activator (t-PA) and thrombectomy, effective therapies for intracerebral hemorrhage (ICH) remain scarce. Stem cell therapies have attracted considerable attention owing to their potential neuro-regenerative ability; preclinical and clinical studies have been conducted to explore strategies for achieving functional recovery following ICH. In this review, we summarize the findings of preclinical studies on stem cell therapies of ICH, with a focus on different animal models, stem cell sources, transplantation methods, and their potential mechanisms of action. We also provide an overview of data from clinical trials to discuss the current status and future perspectives. Understanding the effectiveness and limitations of stem cell therapy and the future prospects could expand the applications of this novel therapeutic approach for ICH.

Bone marrow-derived mesenchymal stem cells overexpressed with miR-182-5p protects against brain injury in a mouse model of cerebral ischemia

BACKGROUND

Toll-like receptor 4 (TLR4) plays a critical role in ischemic brain injury by mediating the inflammatory response. The microRNA miR-185-5p suppresses inflammatory signaling by targeting TLR4. This study investigates whether overexpressing miR-182-5p in bone marrow-derived mesenchymal stem cells (BM-MSCs) could potentiate the neuroprotective effects of BM-MSCs in a mouse model of ischemic brain injury.

METHODS

We isolated BM-MSCs from mice, transfected the cells with miR-182-5p mimic, determined their MSC lineage through flow cytometry analysis of surface markers, examined miR-182-5p and TLR4 expression levels, and injected them into mice undergone middle cerebral artery occlusion (MCAO). MSC transplanted mice were subjected to behavior assays to determine cognitive and motor functions and biochemical analysis to determine neuroinflammation and TLR4/NF-κB in the ischemic hemisphere.

RESULTS

We found that BM-MSCs overexpressing miR-182-5p showed reduced TLR4 expression without affecting their MSC lineage. Mice transplanted with miR-182-5p overexpressing BM-MSCs after MCAO showed significantly improved cognitive and motor functions and reduced neuroinflammation, including suppressed microglial M1 polarization, reduced inflammatory cytokines, and inhibited TLR4/ NF-κB signaling.

CONCLUSION

Our findings suggest that overexpressing miR-182-5p in BM-MSCs can enhance the neuroprotective effects of BM-MSCs against ischemic brain injury by suppressing TLR4-mediated inflammatory response.

Application of stem cells and exosomes in the treatment of intracerebral hemorrhage: an update

Non-traumatic intracerebral hemorrhage is a highly destructive intracranial disease with high mortality and morbidity rates. The main risk factors for cerebral hemorrhage include hypertension, amyloidosis, vasculitis, drug abuse, coagulation dysfunction, and genetic factors. Clinically, surviving patients with intracerebral hemorrhage exhibit different degrees of neurological deficits after discharge. In recent years, with the development of regenerative medicine, an increasing number of researchers have begun to pay attention to stem cell and exosome therapy as a new method for the treatment of intracerebral hemorrhage, owing to their intrinsic potential in neuroprotection and neurorestoration. Many animal studies have shown that stem cells can directly or indirectly participate in the treatment of intracerebral hemorrhage through regeneration, differentiation, or secretion. However, considering the uncertainty of its safety and efficacy, clinical studies are still lacking. This article reviews the treatment of intracerebral hemorrhage using stem cells and exosomes from both preclinical and clinical studies and summarizes the possible mechanisms of stem cell therapy. This review aims to provide a reference for future research and new strategies for clinical treatment.

Mesenchymal Stem Cell Application and Its Therapeutic Mechanisms in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH), a common lethal subtype of stroke accounting for nearly 10–15% of the total stroke disease and affecting two million people worldwide, has a high mortality and disability rate and, thus, a major socioeconomic burden. However, there is no effective treatment available currently. The role of mesenchymal stem cells (MSCs) in regenerative medicine is well known owing to the simplicity of acquisition from various sources, low immunogenicity, adaptation to the autogenic and allogeneic systems, immunomodulation, self-recovery by secreting extracellular vesicles (EVs), regenerative repair, and antioxidative stress. MSC therapy provides an increasingly attractive therapeutic approach for ICH. Recently, the functions of MSCs such as neuroprotection, anti-inflammation, and improvement in synaptic plasticity have been widely researched in human and rodent models of ICH. MSC transplantation has been proven to improve ICH-induced injury, including the damage of nerve cells and oligodendrocytes, the activation of microglia and astrocytes, and the destruction of blood vessels. The improvement and recovery of neurological functions in rodent ICH models were demonstrated via the mechanisms such as neurogenesis, angiogenesis, anti-inflammation, anti-apoptosis, and synaptic plasticity. Here, we discuss the pathological mechanisms following ICH and the therapeutic mechanisms of MSC-based therapy to unravel new cues for future therapeutic strategies. Furthermore, some potential strategies for enhancing the therapeutic function of MSC transplantation have also been suggested.

Maternal omega-3 fatty acid supplementation against prenatal lead exposure induced cognitive impairment in offspring mice

Maternal lead exposure is associated with poor outcomes in fetal brain development such as cognitive dysfunction. Here, we aimed to reveal the effect and mechanism of omega-3 fatty acids in ameliorating maternal lead exposure-induced cognitive impairment in mouse offspring. The activity levels of locomotor and anxiety, memory and learning capacity, spatial working memory, and cognitive behavioral function were determined using the open field test, Morris water maze, Y-maze, and nest-building test, respectively. The protein levels of brain-derived neurotrophic factor (BDNF), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were measured using enzyme-linked immunosorbent assay or Western blot. The mRNA levels of BDNF, tyrosine kinase B (TrkB) and cyclic AMP response element binding protein (CREB) were measured by real-time qPCR. Malondialdehyde (MDA) and anti-oxidants, including SOD, GSH and CAT, were measured using bioassay kits. We found that supplementing omega-3 significantly improved cognitive behavioral function in offspring after prenatal lead exposure. The protein and mRNA levels of BDNF, TrkB and CREB in the prenatal lead exposure group were significantly upregulated by omega-3 supplementation. The MDA level in the prenatal lead exposure group was markedly elevated compared with the control group, which was significantly reduced by omega-3. Omega-3 restored anti-oxidants SOD, GSH and CAT to control levels after prenatal lead exposure. Omega-3 significantly upregulated Nrf2 nuclear expression and HO-1 expression after prenatal lead exposure. Overall, omega-3 supplementation significantly elevated the BDNF/TrkB/CREB pathway and restores anti-oxidants by upregulating the Nrf2/HO-1, thereby improving cognitive function in offspring after prenatal lead exposure.

Recent Stem Cell Research on Hemorrhagic Stroke : An Update

Although technological advances and clinical studies on stem cells have been increasingly reported in stroke, research targeting hemorrhagic stroke is still lacking compared to that targeting ischemic stroke. Studies on hemorrhagic stroke are also being conducted, mainly in the USA and China. However, little research has been conducted in Korea. In reality, stem cell research or treatment is unfamiliar to many domestic neurosurgeons. Nevertheless, given the increased interest in regenerative medicine and the increase of life expectancy, attention should be paid to this topic. In this paper, we summarized pre-clinical rodent studies and clinical trials using stem cells for hemorrhagic stroke. In addition, we discussed results of domestic investigations and future perspectives on stem cell research for a better understanding.

Early-phase administration of human amnion-derived stem cells ameliorates neurobehavioral deficits of intracerebral hemorrhage by suppressing local inflammation and apoptosis

Background

Intracerebral hemorrhage (ICH) is a significant cause of death and disabilities. Recently, cell therapies using mesenchymal stem cells have been shown to improve ICH-induced neurobehavioral deficits. Based on these findings, we designed this study to evaluate the therapeutic efficacy and underlying mechanisms by which human amnion-derived stem cells (hAMSCs) would ameliorate neurobehavioral deficits of ICH-bearing hosts.

Methods

hAMSCs were induced from amnia obtained by cesarean section and administered intravenously to ICH-bearing mice during the acute phase. The mice were then subject to multitask neurobehavioral tests at the subacute phase. We attempted to optimize the dosage and timing of the hAMSC administrations. In parallel with the hAMSCs, a tenfold higher dose of human adipose-derived stem cells (ADSCs) were used as an experimental control. Specimens were obtained from the ICH lesions to conduct immunostaining, flow cytometry, and Western blotting to elucidate the underlying mechanisms of the hAMSC treatment.

Results

The intravenous administration of hAMSCs to the ICH-bearing mice effectively improved their neurobehavioral deficits, particularly when the treatment was initiated at Day 1 after the ICH induction. Of note, the hAMSCs promoted clinical efficacy equivalent to or better than that of hADSCs at 1/10 the cell number. The systemically administered hAMSCs were found in the ICH lesions along with the local accumulation of macrophages/microglia. In detail, the hAMSC treatment decreased the number of CD11b⁺CD45⁺ and Ly6G⁺ cells in the ICH lesions, while splenocytes were not affected. Moreover, the hAMSC treatment decreased the number of apoptotic cells in the ICH lesions. These results were associated with suppression of the protein expression levels of macrophage-related factors iNOS and TNFα.

Conclusions

Intravenous hAMSC administration during the acute phase would improve ICH-induced neurobehavioral disorders. The underlying mechanism was suggested to be the suppression of subacute inflammation and apoptosis by suppressing macrophage/microglia cell numbers and macrophage functions (such as TNFα and iNOS). From a clinical point of view, hAMSC-based treatment may be a novel strategy for the treatment of ICH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02411-3.

Berberine Protects against Neurological Impairments and Blood-Brain Barrier Injury in Mouse Model of Intracerebral Hemorrhage

BACKGROUND

Elevation of AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) signaling can suppress intracerebral hemorrhage (ICH)-induced neurological impairments. As an isoquinoline alkaloid, Berberine exerts neuroprotective effects in neurological disease models with activated AMPK/PGC1α signaling.

AIM

We aim to study the effect of Berberine on ICH-induced brain injury and explore the potential molecular mechanism.

METHODS

ICH model was established in mice through intracerebral injection of autologous whole blood, followed by treatment with Berberine. Neurological impairments were assessed by the modified neurological severity score and behavioral assays. Brain edema and blood-brain barrier (BBB) integrity were assessed by water content in the brain, amount of extravasated Evans blue, and BBB tight junction components. Neuroinflammatory responses were assessed by inflammatory cytokine levels. AMPK/PGC1α signaling was examined by AMPK mRNA expression and phosphorylated AMPK and PGC1α protein levels.

RESULTS

Berberine (200 mg/kg) attenuated ICH-induced neurological deficits, motor and cognitive impairment, and BBB disruption. Berberine also suppressed ICH-induced inflammatory responses indicated by reduced production of inflammatory cytokines. Finally, Berberine drastically elevated AMPK/PGC1α signaling in the hemisphere of ICH mice.

CONCLUSION

Our findings suggest that Berberine plays an important neuroprotective role against ICH-induced neurological impairments and BBB injury, probably by inhibition of inflammation and activation of AMPK/PGC1α signaling.

Cordycepin Ameliorates Intracerebral Hemorrhage Induced Neurological and Cognitive Impairments Through Reducing Anti-Oxidative Stress in a Mouse Model

OBJECTIVES

The nerve damage and cognitive impairment caused by intracerebral hemorrhage (ICH) seriously affect the quality of life of patients. Cordycepin has been reported to have antioxidant and neuroprotective functions. However, the therapeutic effect of cordycepin on cognitive impairment caused by ICH is still unclear.

MATERIALS AND METHODS

Autologous whole blood was injected into the basal ganglia to construct a mouse ICH model. The Modified Neurological Severity Score was used to assess nerve damage in mice. The wet/dry method was used to detect brain water content. Open field test was used to assess the anxiety of mice. Morris water maze testing, Y-maze test and nest-building test were used to evaluate the cognitive function of mice. qRT-PCR and western blotting assay were used to evaluate the expression of genes.

RESULTS

Cordycepin treatment could ameliorate ICH-induced neurological deficits, brain edema, anxiety, cognitive impairments, oxidative stress and antioxidant capacity in ICH mice.

CONCLUSION

Cordycepin ameliorates ICH-induced neurological and cognitive impairments through reducing anti-oxidative stress in mouse model.

Central Nervous System Tissue Regeneration after Intracerebral Hemorrhage: The Next Frontier

Despite marked advances in surgical techniques and understanding of secondary brain injury mechanisms, the prognosis of intracerebral hemorrhage (ICH) remains devastating. Harnessing and promoting the regenerative potential of the central nervous system may improve the outcomes of patients with hemorrhagic stroke, but approaches are still in their infancy. In this review, we discuss the regenerative phenomena occurring in animal models and human ICH, provide results related to cellular and molecular mechanisms of the repair process including by microglia, and review potential methods to promote tissue regeneration in ICH. We aim to stimulate research involving tissue restoration after ICH.

17β-Estradiol Attenuates Intracerebral Hemorrhage-Induced Blood-Brain Barrier Injury and Oxidative Stress Through SRC3-Mediated PI3K/Akt Signaling Pathway in a Mouse Model

Estrogen is neuroprotective in brain injury models, and steroid receptor cofactor 3 (SRC3) mediates estrogen signaling. We aimed to investigate whether and how SRC3 is involved in the neuroprotective effects of 17ß-estradiol (E2) in a mouse model of intracerebral hemorrhage (ICH). Ovariectomized female mice were treated with E2 after autologous blood injection-induced ICH. Brain damage was assessed by neurological deficit score, brain water content, and oxidative stress levels. Blood–brain barrier (BBB) integrity was evaluated by Evan's blue extravasation and claudin-5, ZO-1, and occludin levels. SRC3 expression and PI3K/Akt signaling pathway were examined in ICH mice treated with E2. The effect of SRC3 on E2-mediated neuroprotection was determined by examining neurological outcomes in SRC3-deficient mice undergone ICH and E2 treatment. We found that E2 alleviated ICH-induced brain edema and neurological deficits, protected BBB integrity, and suppressed oxidative stress. E2 enhanced SRC3 expression and PI3K-/Akt signaling pathway. SRC3 deficiency abolished the protective effects of E2 on ICH-induced neurological deficits, brain edema, and BBB integrity. Our results suggest that E2 suppresses ICH-induced brain injury and SRC3 plays a critical role in E2-mediated neuroprotection.

SRC-3 Deficiency Exacerbates Neurological Deficits in a Mouse Model of Intracerebral Hemorrhage: Role of Oxidative Stress

Intracerebral hemorrhage (ICH) causes long term neurological abnormality or death. Oxidative stress is closely involved in ICH mediated brain damage. Steroid receptor cofactor 3 (SRC-3), a p160 family member, is widely expressed in the brain and regulates transactivation of Nrf2, a key component of antioxidant response. Our study aims to test if SRC-3 is implicated in ICH mediated brain injury. We first examined levels of SRC-3 and oxidative stress in the brain of mice following ICH and analyzed their correlation. Then ICH was induced in wild type (WT) and SRC-3 knock out mice and how SRC-3 deletion affected ICH induced brain damage, oxidative stress and behavioral outcome was assessed. We found that SRC-3 mRNA and protein expression levels were reduced gradually after ICH induction in WT mice along with an increase in oxidative stress levels. Correlation analysis revealed that SRC-3 mRNA levels negatively correlated with oxidative stress. Deletion of SRC-3 further increased ICH induced brain edema, neurological deficit score and oxidative stress and exacerbated ICH induced behavioral abnormality including motor dysfunction and cognitive impairment. Our findings suggest that SRC-3 is involved in ICH induced brain injury, probably through modulation of oxidative stress.

The Effect of Proinflammatory Cytokines on the Proliferation, Migration and Secretory Activity of Mesenchymal Stem/Stromal Cells (WJ-MSCs) under 5% O2 and 21% O2 Culture Conditions

Treatment with Mesenchymal Stem/Stromal Cells (MSCs) in clinical trials is becoming one of the most-popular and fast-developing branches of modern regenerative medicine, as it is still in an experimental phase. The cross-section of diseases to which these cells are applied is very wide, ranging from degenerative diseases, through autoimmune processes and to acute inflammatory diseases, e.g., viral infections. Indeed, now that first clinical trials applying MSCs against COVID-19 have started, important questions concern not only the therapeutic properties of MSCs, but also the changes that might occur in the cell features as a response to the "cytokine storm" present in the acute phase of an infection and capable of posing a risk to a patient. The aim of our study was thus to assess changes potentially occurring in the biology of MSCs in the active inflammatory environment, e.g., in regards to the cell cycle, cell migration and secretory capacity. The study using MSCs derived from Wharton's jelly (WJ-MSCs) was conducted under two aerobic conditions: 21% O2 vs. 5% O2, since oxygen concentration is one of the key factors in inflammation. Under both oxygen conditions cells were exposed to proinflammatory cytokines involved significantly in acute inflammation, i.e., IFNγ, TNFα and IL-1β at different concentrations. Regardless of the aerobic conditions, WJ-MSCs in the inflammatory environment do not lose features typical for mesenchymal cells, and their proliferation dynamic remains unchanged. Sudden fluctuations in proliferation, the early indicator of potential genetic disturbance, were not observed, while the cells' migration activity increased. The presence of pro-inflammatory factors was also found to increase the secretion of such anti-inflammatory cytokines as IL-4 and IL-10. It is concluded that the inflammatory milieu in vitro does not cause phenotype changes or give rise to proliferation disruption of WJ-MSCs, and nor does it inhibit the secretory properties providing for their use against acute inflammation.

Mechanism of White Matter Injury and Promising Therapeutic Strategies of MSCs After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the most fatal subtype of stroke with high disability and high mortality rates, and there is no effective treatment. The predilection site of ICH is in the area of the basal ganglia and internal capsule (IC), where exist abundant white matter (WM) fiber tracts, such as the corticospinal tract (CST) in the IC. Proximal or distal white matter injury (WMI) caused by intracerebral parenchymal hemorrhage is closely associated with poor prognosis after ICH, especially motor and sensory dysfunction. The pathophysiological mechanisms involved in WMI are quite complex and still far from clear. In recent years, the neuroprotection and repairment capacity of mesenchymal stem cells (MSCs) has been widely investigated after ICH. MSCs exert many unique biological effects, including self-recovery by producing growth factors and cytokines, regenerative repair, immunomodulation, and neuroprotection against oxidative stress, providing a promising cellular therapeutic approach for the treatment of WMI. Taken together, our goal is to discuss the characteristics of WMI following ICH, including the mechanism and potential promising therapeutic targets of MSCs, aiming at providing new clues for future therapeutic strategies.

Mesenchymal Stem Cells Transplantation in Intracerebral Hemorrhage: Application and Challenges

Intracerebral hemorrhage (ICH) is one of the leading causes of death and long-term disability worldwide. Mesenchymal stem cell (MSC) therapies have demonstrated improved outcomes for treating ICH-induced neuronal defects, and the neural network reconstruction and neurological function recovery were enhanced in rodent ICH models through the mechanisms of neurogenesis, angiogenesis, anti-inflammation, and anti-apoptosis. However, many key issues associated with the survival, differentiation, and safety of grafted MSCs after ICH remain to be resolved, which hinder the clinical translation of MSC therapy. Herein, we reviewed an overview of the research status of MSC transplantation after ICH in different species including rodents, swine, monkey, and human, and the challenges for MSC-mediated ICH recovery from pathological microenvironment have been summarized. Furthermore, some efficient strategies for the outcome improvement of MSC transplantation were proposed.

Behavioral tests in rodent models of stroke

Rodents are the most widely used experimental animals in stroke research due to their similar vascular anatomy, high reproductive rates, and availability of transgenic models. However, the difficulties in assessing higher brain functions, such as cognition and memory, in rodents decrease the translational potential of these studies. In this review, we summarize commonly used motor/sensorimotor and cognition tests in rodent models of stroke. Specifically, we first briefly introduce the objective and procedure of each behavioral test. Next, we summarize the application of each test in both ischemic stroke and hemorrhagic stroke. Last, the advantages and disadvantages of these tests in assessing stroke outcome are discussed. This review summarizes commonly used behavioral tests in stroke studies and compares their applications in different stroke types.

Early Reperfusion Following Ischemic Stroke Provides Beneficial Effects, Even After Lethal Ischemia with Mature Neural Cell Death

Ischemic stroke is a critical disease caused by cerebral artery occlusion in the central nervous system (CNS). Recent therapeutic advances, such as neuroendovascular intervention and thrombolytic therapy, have allowed recanalization of occluded brain arteries in an increasing number of stroke patients. Although previous studies have focused on rescuing neural cells that still survive despite decreased blood flow, expanding the therapeutic time window may allow more patients to undergo reperfusion in the near future, even after lethal ischemia, which is characterized by death of mature neural cells, such as neurons and glia. However, it remains unclear whether early reperfusion following lethal ischemia results in positive outcomes. The present study used two ischemic mouse models—90-min transient middle cerebral artery occlusion (t-MCAO) paired with reperfusion to induce lethal ischemia and permanent middle cerebral artery occlusion (p-MCAO)—to investigate the effect of early reperfusion up to 8 w following MCAO. Although early reperfusion following 90-min t-MCAO did not rescue mature neural cells, it preserved the vascular cells within the ischemic areas at 1 d following 90-min t-MCAO compared to that following p-MCAO. In addition, early reperfusion facilitated the healing processes, including not only vascular but also neural repair, during acute and chronic periods and improved recovery. Furthermore, compared with p-MCAO, early reperfusion after t-MCAO prevented behavioral symptoms of neurological deficits without increasing negative complications, including hemorrhagic transformation and mortality. These results indicate that early reperfusion provides beneficial effects presumably via cytoprotective and regenerative mechanisms in the CNS, suggesting that it may be useful for stroke patients that experienced lethal ischemia.

Potential of stem cell therapy in intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is a common disease associated with high mortality and morbidity. The treatment of patients with ICH includes medical and surgical interventions. New areas of surgical intervention have been focused on the evacuation of hematoma through minimally invasive neurosurgery. In contrast, there have been no significant advances in the development of medical interventions for functional recovery after ICH. Stem cells exert multiple therapeutic functions and have emerged as a promising treatment strategy. Herein, we summarized the pathophysiology of ICH and its treatment targets, and we introduced the therapeutic mechanisms of stem cells (e.g. neutrotrophy and neuroregeneration). Moreover, we reviewed and summarized the experimental designs of the preclinical studies, including the types of cells and the timing and routes of stem cell administration. We further listed and reviewed the completed/published and ongoing clinical trials supporting the safety and efficacy of stem cell therapy in ICH. The limitations of translating preclinical studies into clinical trials and the objectives of future studies were discussed. In conclusion, current literatures showed that stem cell therapy is a promising treatment in ICH and further translation research on judiciously selected group of patients is warranted before it can be extensively applied in clinical practice.

Overexpression of CX3CR1 in Adipose-Derived Stem Cells Promotes Cell Migration and Functional Recovery After Experimental Intracerebral Hemorrhage

Stem cell therapy has emerged as a new promising therapeutic strategy for intracerebral hemorrhage (ICH). However, the efficiency of stem cell therapy is partially limited by low retention and engraftment of the delivered cells. Therefore, it’s necessary to improve the migration ability of stem cells to the injured area in order to save the costs and duration of cell preparation. This study aimed to investigate whether overexpression of CX3CR1, the specific receptor of chemokine fractalkine (FKN), in adipose-derived stem cells (ADSCs) can stimulate the cell migration to the injured area in the brain, improve functional recovery and protect against cell death following experimental ICH. ADSCs were isolated from subcutaneous adipose tissues of rats. ICH was induced by means of an injection of collagenase type VII. ELISA showed that the expression levels of fractalkine/FKN were increased at early time points, with a peak at day 3 after ICH. And it was found that different passages of ADSCs could express the chemokine receptor CX3CR1. Besides, the chemotactic movements of ADSCs toward fractalkine have been verified by transwell migration assay. ADSCs overexpressing CX3CR1 were established through lentivirus transfection. We found that after overexpression of CX3CR1 receptor, the migration ability of ADSCs was increased both in vitro and in vivo. In addition, reduced cell death and improved sensory and motor functions were seen in the mice ICH model. Thus, ADSCs overexpression CX3CR1 might be taken as a promising therapeutic strategy for the treatment of ICH.