Cellular and Noncellular Approaches for Repairing the Damaged Blood-CNS-Barrier in Amyotrophic Lateral Sclerosis.

Numerous reports have demonstrated the breakdown of the blood-CNS barrier (B-CNS-B) in amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease. Re-establishing barrier integrity in the CNS is critical to prevent further motor neuron degeneration from harmful components in systemic circulation. Potential therapeutic strategies for repairing the B-CNS-B may be achieved by the replacement of damaged endothelial cells (ECs) via stem cell administration or enhancement of endogenous EC survival through the delivery of bioactive particles secreted by stem cells. These cellular and noncellular approaches are thoroughly discussed in the present review. Specific attention is given to certain stem cell types for EC replacement. Also, various nanoparticles secreted by stem cells as well as other biomolecules are elucidated as promising agents for endogenous EC repair. Although the noted in vitro and in vivo studies show the feasibility of the proposed therapeutic approaches to the repair of the B-CNS-B in ALS, further investigation is needed prior to clinical transition.

Transplanted Human Bone Marrow Endothelial Progenitor Cells Prolong Functional Benefits and Extend Survival of ALS Mice Likely via Blood-Spinal Cord Barrier Repair.

Amyotrophic lateral sclerosis (ALS) is a multifactorial disease with one of these factors being an impaired blood-spinal cord barrier (BSCB). In order to block harmful components in systemic circulation from accessing the CNS, barrier damage needs alleviation. Recently, we found that symptomatic ALS animals treated with intravenously delivered human bone marrow-derived CD34+ (hBM34+) cells or endothelial progenitor cells (hBMEPCs) showed delayed disease progression for 4 weeks post-transplant via BSCB repair. However, despite noted benefits from transplanted human bone marrow-derived stem cells, long-term effects of transplanted cells in ALS mice remain undetermined. This study aimed to determine prolonged effects of single equal doses of hBM34+ cells and hBMEPCs systemically transplanted into symptomatic G93A SOD1 mice on behavioral disease outcomes and mouse lifespan. Results showed that transplanted hBMEPCs better ameliorated disease behavioral outcomes than hBM34 + cells until near end-stage disease and significantly increased lifespan vs. media-treated mice. These results provide important evidence that transplanted hBMEPCs prolonged functional benefits and extended survival of ALS mice, potentially by repairing the damaged BSCB. However, due to modestly increased lifespan of hBMEPC-treated mice, repeated cell transplants into symptomatic ALS mice may more effectively delay motor function deficit and extend lifespan by continuous reparative processes via replacement of damaged endothelial cells during disease progression.

Continuous vagus nerve stimulation exerts beneficial effects on rats with experimentally induced Parkinson's disease: Evidence suggesting involvement of a vagal afferent pathway.

BACKGROUND: Vagus nerve stimulation (VNS) exerts neuroprotective and anti-inflammatory effects in preclinical models of central nervous system disorders, including Parkinson's disease (PD). VNS setting applied for experimental models is limited into single-time or intermittent short-duration stimulation. We developed a VNS device which could deliver continuous stimulation for rats. To date, the effects of vagal afferent- or efferent-selective stimulation on PD using continuous electrical stimulation remains to be determined. OBJECTIVE: To investigate the effects of continuous and selective stimulation of vagal afferent or efferent fiber on Parkinsonian rats. METHODS: Rats were divided into 5 group: intact VNS, afferent VNS (left VNS in the presence of left caudal vagotomy), efferent VNS (left VNS in the presence of left rostral vagotomy), sham, vagotomy. Rats underwent the implantation of cuff-electrode on left vagus nerve and 6-hydroxydopamine administration into the left striatum simultaneously. Electrical stimulation was delivered just after 6-OHDA administration and continued for 14 days. In afferent VNS and efferent VNS group, the vagus nerve was dissected at distal or proximal portion of cuff-electrode to imitate the selective stimulation of afferent or efferent vagal fiber respectively. RESULTS: Intact VNS and afferent VNS reduced the behavioral impairments in cylinder test and methamphetamine-induced rotation test, which were accompanied by reduced inflammatory glial cells in substantia nigra with the increased density of the rate limiting enzyme in locus coeruleus. In contrast, efferent VNS did not exert any therapeutic effects. CONCLUSION: Continuous VNS promoted neuroprotective and anti-inflammatory effect in experimental PD, highlighting the crucial role of the afferent vagal pathway in mediating these therapeutic outcomes.

Getting the guts to expand stroke treatment: The potential for microbiome targeted therapies.

AIMS: This review focuses on the recent literature regarding the role of the gut-brain axis (GBA) following ischemic stroke. DISCUSSION: Stroke is the 5th leading cause of death and disability in the United States; however, few therapies have been developed to improve prognoses. There is a plethora of evidence suggesting peripheral inflammatory responses play a large role in the pathogenesis of stroke. Additionally, hyperglycemic conditions may play a significant role in worsening stroke outcomes due to microbiome dysbiosis. CONCLUSION: Recent research has illuminated the vital role of the GBA in propagating poor clinical outcomes, such as hemorrhagic transformation, following ischemic stroke. Considering this detrimental consequence of stroke, and the apparent role of the GBA role, future therapeutics should aim to mitigate this peripheral contribution to stroke complications.

Multinuclear MRI Reveals Early Efficacy of Stem Cell Therapy in Stroke.

Compromised adult human mesenchymal stem cells (hMSC) can impair cell therapy efficacy and further reverse ischemic recovery. However, in vitro assays require extended passage to characterize cells, limiting rapid assessment for therapeutic potency. Multinuclear magnetic resonance imaging and spectroscopy (MRI/S) provides near real-time feedback on disease progression and tissue recovery. Applied to ischemic stroke, 23Na MRI evaluates treatment efficacy within 24 h after middle cerebral artery occlusion, showing recovery of sodium homeostasis and lesion reduction in specimens treated with hMSC while 1H MRS identifies reduction in lactate levels. This combined metric was confirmed by evaluating treatment groups receiving healthy or compromised hMSC versus vehicle (sham saline injection) over 21 days. Behavioral tests to assess functional recovery and cell analysis for immunomodulatory and macrophage activity to detect hMSC potency confirm MR findings. Clinically, these MR metrics may prove critical to early evaluations of therapeutic efficacy and overall stroke recovery.

Patching Up the Permeability: The Role of Stem Cells in Lessening Neurovascular Damage in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a debilitating disease with poor prognosis. The pathophysiology of ALS is commonly debated, with theories involving inflammation, glutamate excitotoxity, oxidative stress, mitochondria malfunction, neurofilament accumulation, inadequate nutrients or growth factors, and changes in glial support predominating. These underlying pathological mechanisms, however, act together to weaken the blood brain barrier and blood spinal cord barrier, collectively considered as the blood central nervous system barrier (BCNSB). Altering the impermeability of the BCNSB impairs the neurovascular unit, or interdependent relationship between the brain and advances the concept that ALS is has a significant neurovascular component contributing to its degenerative presentation. This unique categorization of ALS opens a variety of treatment options targeting the reestablishment of BCNSB integrity. This review will critically assess the evidence implicating the significant neurovascular components of ALS pathophysiology, while also offering an in-depth discussion regarding the use of stem cells to repair these pathological changes within the neurovascular unit.

Inflammatory gut as a pathologic and therapeutic target in Parkinson's disease.

Parkinson's disease (PD) remains a significant unmet clinical need. Gut dysbiosis stands as a PD pathologic source and therapeutic target. Here, we assessed the role of the gut-brain axis in PD pathology and treatment. Adult transgenic (Tg) α-synuclein-overexpressing mice served as subjects and were randomly assigned to either transplantation of vehicle or human umbilical cord blood-derived stem cells and plasma. Behavioral and immunohistochemical assays evaluated the functional outcomes following transplantation. Tg mice displayed typical motor and gut motility deficits, elevated α-synuclein levels, and dopaminergic depletion, accompanied by gut dysbiosis characterized by upregulation of microbiota and cytokines associated with inflammation in the gut and the brain. In contrast, transplanted Tg mice displayed amelioration of motor deficits, improved sparing of nigral dopaminergic neurons, and downregulation of α-synuclein and inflammatory-relevant microbiota and cytokines in both gut and brain. Parallel in vitro studies revealed that cultured dopaminergic SH-SY5Y cells exposed to homogenates of Tg mouse-derived dysbiotic gut exhibited significantly reduced cell viability and elevated inflammatory signals compared to wild-type mouse-derived gut homogenates. Moreover, treatment with human umbilical cord blood-derived stem cells and plasma improved cell viability and decreased inflammation in dysbiotic gut-exposed SH-SY5Y cells. Intravenous transplantation of human umbilical cord blood-derived stem/progenitor cells and plasma reduced inflammatory microbiota and cytokine, and dampened α-synuclein overload in the gut and the brain of adult α-synuclein-overexpressing Tg mice. Our findings advance the gut-brain axis as a key pathological origin, as well as a robust therapeutic target for PD.

Sequestration of Inflammation in Parkinson's Disease via Stem Cell Therapy.

Parkinson's disease is the second most common neurodegenerative disease. Insidious and progressive, this disorder is secondary to the gradual loss of dopaminergic signaling and worsening neuroinflammation, affecting patients' motor capabilities. Gold standard treatment includes exogenous dopamine therapy in the form of levodopa-carbidopa, or surgical intervention with a deep brain stimulator to the subcortical basal ganglia. Unfortunately, these therapies may ironically exacerbate the already pro-inflammatory environment. An alternative approach may involve cell-based therapies. Cell-based therapies, whether endogenous or exogenous, often have anti-inflammatory properties. Alternative strategies, such as exercise and diet modifications, also appear to play a significant role in facilitating endogenous and exogenous stem cells to induce an anti-inflammatory response, and thus are of unique interest to neuroinflammatory conditions including Parkinson's disease. Treating patients with current gold standard therapeutics and adding adjuvant stem cell therapy, alongside the aforementioned lifestyle modifications, may ideally sequester inflammation and thus halt neurodegeneration.

Transplantation of modified human bone marrow-derived stromal cells affords therapeutic effects on cerebral ischemia in rats.

AIMS: SB623 cells are human bone marrow stromal cells transfected with Notch1 intracellular domain. In this study, we examined potential regenerative mechanisms underlying stereotaxic transplantation of SB623 cells in rats with experimental acute ischemic stroke. METHODS: We prepared control group, empty capsule (EC) group, SB623 cell group (SB623), and encapsulated SB623 cell (eSB623) group. Transient middle cerebral artery occlusion (MCAO) was performed on day 0, and 24 h after MCAO, stroke rats received transplantation into the envisioned ischemic penumbra. Modified neurological severity score (mNSS) was evaluated, and histological evaluations were performed. RESULTS: In the mNSS, SB623 and eSB623 groups showed significant improvement compared to the other groups. Histological analysis revealed that the infarction area in SB623 and eSB623 groups was reduced. In the eSB623 group, robust cell viability and neurogenesis were detected in the subventricular zone that increased significantly compared to all other groups. CONCLUSION: SB623 cells with or without encapsulation showed therapeutic effects on ischemic stroke. Encapsulated SB623 cells showed enhanced neurogenesis and increased viability inside the capsules. This study reveals the mechanism of secretory function of transplanted SB623 cells, but not cell-cell interaction as primarily mediating the cells' functional benefits in ischemic stroke.

The Role of Concomitant Nrf2 Targeting and Stem Cell Therapy in Cerebrovascular Disease.

Despite the reality that a death from cerebrovascular accident occurs every 3.5 min in the United States, there are few therapeutic options which are typically limited to a narrow window of opportunity in time for damage mitigation and recovery. Novel therapies have targeted pathological processes secondary to the initial insult, such as oxidative damage and peripheral inflammation. One of the greatest challenges to therapy is the frequently permanent damage within the CNS, attributed to a lack of sufficient neurogenesis. Thus, recent use of cell-based therapies for stroke have shown promising results. Unfortunately, stroke-induced inflammatory and oxidative damage limit the therapeutic potential of these stem cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been implicated in endogenous antioxidant and anti-inflammatory activity, thus presenting an attractive target for novel therapeutics to enhance stem cell therapy and promote neurogenesis. This review assesses the current literature on the concomitant use of stem cell therapy and Nrf2 targeting via pharmaceutical and natural agents, highlighting the need to elucidate both upstream and downstream pathways in optimizing Nrf2 treatments in the setting of cerebrovascular disease.

Apolipoprotein A1 Enhances Endothelial Cell Survival in an In Vitro Model of ALS.

Altered lipoprotein metabolism is considered a pathogenic component of amyotrophic lateral sclerosis (ALS). Apolipoprotein A1 (ApoA1), a major high-density lipoprotein (HDL) protein, is associated with prevention of vascular damage. However, ApoA1's effects on damaged endothelium in ALS are unknown. This study aimed to determine therapeutic potential of ApoA1 for endothelial cell (EC) repair under a pathologic condition reminiscent of ALS. We performed in vitro studies using mouse brain ECs (mBECs) exposed to plasma from symptomatic G93A SOD1 mice. Dosage effects of ApoA1, including inhibition of the phosphoinoside 3-kinase (PI3K)/Akt signaling pathway and integration of ApoA1 into mBECs were examined. Also, human bone marrow-derived endothelial progenitor cells (hBM-EPCs) and mBECs were co-cultured without cell contact to establish therapeutic mechanism of hBM-EPC transplantation. Results showed that ApoA1 significantly reduced mBEC death via the PI3K/Akt downstream signaling pathway. Also, ApoA1 was incorporated into mBECs as confirmed by blocked ApoA1 cellular integration. Co-culture system provided evidence that ApoA1 was secreted by hBM-EPCs and incorporated into injured mBECs. Thus, our study findings provide important evidence for ApoA1 as a potential novel therapeutic for endothelium protection in ALS. This in vitro study lays the groundwork for further in vivo research to fully determine therapeutic effects of ApoA1 in ALS.

Effects of Lovastatin on Brain Cancer Cells.

Although brain tumors occur less frequently than other forms of cancer, they have one of the bleakest prognoses with low survival rates. The conventional treatment for brain tumors includes surgery, radiotherapy, and chemotherapy. However, resistance to treatment remains a problem with recurrence shortly following. The resistance to treatment may be caused by cancer stem cells (CSCs), a subset of brain tumor cells with the affinity for self-renewal and differentiation into multiple cell lineages. An emerging approach to targeting CSCs in brain tumors is through repurposing the lipid-lowering medication, lovastatin. Lovastatin is a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor that impacts the mevalonate pathway. The inhibition of intermediates in the mevalonate pathway affects signaling cascades and oncogenes associated with brain tumor stem cells (BTSC). In this review, we show the possible mechanisms where lovastatin can target BTSC for different varieties of malignant brain tumors.

Exosomes Derived From Mesenchymal Stem Cells Pretreated With Ischemic Rat Heart Extracts Promote Angiogenesis via the Delivery of DMBT1.

Mesenchymal stem cell-derived exosomes (MSC-Exos) have been shown to promote angiogenesis. Treating MSCs with ischemic rat brain extracts was sufficient to augment their benefits in stroke. However, no similar analyses of ischemic heart extracts have been performed to date. We aim to determine whether MSC-Exos derived from MSCs pretreated with ischemic rat heart extract were able to promote angiogenesis and to clarify underlying mechanisms. ELISA (enzyme-linked immunosorbent assay) of heart extracts revealed a significant increase of vascular endothelial growth factor (VEGF) at 24 h post-MI (myocardial infarction) modeling, and time-dependent decreases in hypoxia inducible factor-1α (HIF-1α). MTT and wound healing assays revealed human umbilical vein endothelial cells (HUVECs) migration and proliferation increased following MSCE-Exo treatment (exosomes derived from MSC pretreated with ischemic heart extracts of 24 h post-MI) relative to MSCN-Exo treatment (exosomes derived from MSC pretreated with normal heart extracts). Proteomic analyses of MSCE-Exo and MSCN-Exo were conducted to screen for cargo proteins promoting angiogenesis. Result revealed several angiogenesis-related proteins were upregulated in MSCE-Exo, including DMBT1 (deleted in malignant brain tumors 1). When DMBT1 was silenced in MSCs, HUVECs with MSCDMBT1 RNAi-Exo treatment exhibited impaired proliferative and migratory activity and reductions of DMBT1, p-Akt, ß-catenin, and VEGF. To explore how ischemic heart extracts took effects, ELISA was conducted showing a significant increase of IL-22 at 24 h post-MI modeling. P-STAT3, IL22RA1, DMBT1, and VEGF proteins were increased in MSCE relative to MSCN, and VEGF and DMBT1 were increased in MSCE-Exos. Together, these suggest that IL-22 upregulation in ischemic heart extracts can increase DMBT1 in MSCs. Exosomes derived from those MSCs deliver DMBT1 to HUVECs, thereby enhancing their migratory and proliferative activity.

Unveiling the mechanisms of hematopoietic stem cell transplantation: Balancing cell senescence and proliferation in cancer and beyond.

In a recent Nature Medicine publication, Sailor et al.1 elucidate the complex mechanism of hematopoietic stem cell transplantation (HSCT) and chemotherapy, highlighting the occurrence of host microglia senescence coupled with donor macrophage engraftment. These findings warrant a more in-depth understanding of HSCT and its adjunctive therapies to enhance current and future treatments for cancer and a plethora of pro-inflammatory disorders.

Neuroinflammation, Stem Cells, and Stroke.

Stroke remains a significant unmet clinical need with few treatment options that have a very narrow therapeutic window, thereby causing massive mortality and morbidity in the United States and around the world. Accordingly, finding safe and effective novel treatments with a wider therapeutic window stands as an urgent need in stroke. The progressive inflammation that occurs centrally and peripherally after stroke serves as a unique therapeutic target to retard and even halt the secondary cell death. Stem cell therapy represents a potent approach that can diminish inflammation in both the stroke brain and periphery (eg, spleen), advancing a paradigm shift from a traditionally brain-focused therapy to treating stroke as a neurological disorder with a significant peripheral pathology. The purpose of this review article is to highlight the inflammation-mediated secondary cell death that plagues both brain and spleen in stroke and to evaluate the therapeutic potential of stem cell therapy in dampening these inflammatory responses.

Contraceptive drug, Nestorone, enhances stem cell-mediated remodeling of the stroke brain by dampening inflammation and rescuing mitochondria.

Ischemic stroke remains a significant unmet need causing massive mortality and morbidity due to few treatment options with limited therapeutic window. The progestin Nestorone® (segesterone acetate) displays high affinity for the progesterone receptor in exerting its potent birth control and hormone replacement therapy. Accumulating evidence implicates a new utility of Nestorone in affording neuroprotection in a variety of central nervous system diseases, including stroke. However, the mechanism of action mediating Nestorone's neuroprotection in stroke remains unknown. Here, we showed that stand-alone treatments of Nestorone or human amniotic fluid-derived stem cells (hAFSc), but more pronounced with their combined treatment, led to significant improvements in behavioral function and reductions in infarction and peri-infarct cell loss in adult rats with ischemic stroke. We detected significantly lower levels of pro-inflammatory signals (OX6 and IBA1) coupled with enhanced levels of stem cell proliferation (Ki67) and differentiation (DCX and MAP2) in both brain and spleen of stroke rats that received stand-alone or combined treatments of Nestorone and hAFSc. In concert, the in vitro oxygen-glucose deprivation stroke model revealed that neural stem cells treated with Nestorone exhibited increased stem cell proliferation and differentiation that was accompanied by rescue of the mitochondrial respiratory activity characterized by reduced mitochondrial reactive oxygen species, increased ATP, elevated mitochondrial deacetylase Sirtuin 3 (SIRT3), and a normalized ratio of acetyl-superoxide dismutase 2 (Ac-SOD2)/SOD2, suggesting the key role of mitochondrial metabolism and oxidative protection in Nestorone's therapeutic effects in stroke.

Mesenchymal Stromal Cells in Ischemic Brain Injury.

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

A review of the pathology and treatment of TBI and PTSD.

This literature review focuses on the underlying pathophysiology of TBI and PTSD symptoms, while also examining the plethora of stem cell treatment options to ameliorate these neuronal and functional changes. As more veterans return suffering from TBI and/or PTSD, it is vital that researchers discover novel therapies to mitigate the detrimental symptoms of both diagnoses. A variety of stem cell treatments have been studied and offer hopeful options for TBI and PTSD recovery.

Extended Ischemic Recovery After Implantation of Human Mesenchymal Stem Cell Aggregates Indicated by Sodium MRI at 21.1 T.

Extended therapeutic application remains a significant issue in the use of stem cell therapies to treat ischemic stroke. Along these lines, neurological recovery in a rodent model of ischemic stroke was evaluated following implantation of human mesenchymal stem cell aggregates (hMSC-agg), labeled with micron-sized particles of iron oxide, directly into the lateral ventricle contralateral to the ischemic lesion hemisphere. Longitudinally, disease progression and response to hMSC-agg therapy were assessed by 1H and 23Na magnetic resonance imaging (MRI) at 21.1 T to investigate cellular localization, migration, and recovery over an extended timeframe. MRI provides quantifiable metrics of tissue status through sodium distributions in addition to traditional proton imaging. Quantitative 23Na MRI revealed a significant decrease of sodium concentrations following hMSC aggregate implantation, indicating recovery of homeostasis. This result correlates positively with extended neurological recovery assessed by behavioral analysis and immunohistochemistry. These findings demonstrate the potential of implanted hMSC aggregate therapy to provide extended treatment for ischemic stroke, as well as the robustness of MRI for monitoring such approaches. This method potentially can be translated to a clinical setting for the assessment of extended cell therapy efficacy.