Implantation of human umbilical cord mesenchymal stem cells for ischemic stroke: perspectives and challenges

Efficacy and safety of mesenchymal stem cell therapies for ischemic stroke: a systematic review and meta-analysis

BACKGROUND

The efficacy and safety of mesenchymal stem cells (MSCs) in the treatment of ischemic stroke (IS) remains controversial. Therefore, this study aimed to evaluate the efficacy and safety of MSCs for IS.

METHODS

A literature search until May 23, 2023, was conducted using PubMed, EMBASE, the Cochrane Library, and the Web of Science to identify studies on stem cell therapy for IS. Interventional and observational clinical studies of MSCs in patients with IS were included, and the safety and efficacy were assessed. Two reviewers extracted data and assessed the quality independently. The meta-analysis was performed using RevMan5.4.

RESULTS

Fifteen randomized controlled trials (RCTs) and 15 non-randomized trials, including 1217 patients (624 and 593 in the intervention and control arms, respectively), were analyzed. MSCs significantly improved patients' activities of daily living according to the modified Rankin scale (mean difference [MD]: -0.26; 95% confidence interval [CI]: -0.50 to -0.01; P = .04) and National Institutes of Health Stroke Scale score (MD: -1.69; 95% CI: -2.66 to -0.73; P < .001) in RCTs. MSC treatment was associated with lower mortality rates in RCTs (risk ratio: 0.44; 95% CI: 0.28-0.69; P < .001). Fever and headache were among the most reported adverse effects.

CONCLUSIONS

Based on our review, MSC transplantation improves neurological deficits and daily activities in patients with IS. In the future, prospective studies with large sample sizes are needed for stem cell studies in ischemic stroke. This meta-analysis has been registered at PROSPERO with CRD42022347156.

Effects of extracellular vesicles for ischemic stroke: A meta‑analysis of preclinical studies

Ischemic stroke is a common occurrence worldwide, posing a severe threat to human health and leading to negative financial impacts. Currently available treatments still have numerous limitations. As research progresses, extracellular vesicles are being found to have therapeutic potential in ischemic stroke. In the present study, the literature on extracellular vesicle therapy in animal studies of ischemic stroke was screened by searching databases, including PubMed, Embase, Medline, Web of Science and the Cochrane Library. The main outcomes of the present study were the neurological function score, apoptotic rate and infarct volumes. The secondary outcomes were pro-inflammatory factors, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6. The study quality was assessed using the CAMARADES Checklist. Subgroup analyses were performed to evaluate factors influencing extracellular vesicle therapy. Review Man3ager5.3 was used for data analysis. A total of 20 relevant articles were included in the present meta-analysis. The comprehensive analysis revealed that extracellular vesicles exerted a significant beneficial effect on neurobehavioral function, reducing the infarct volume and decreasing the apoptotic rate. Moreover, extracellular vesicles were found to promote nerve recovery by inhibiting pro-inflammatory factors (TNF-α, IL-1β and IL-6). On the whole, the present meta-analysis examined the combined effects of extracellular vesicles on nerve function, infarct volume, apoptosis and inflammation, which provides a foundation for the clinical study of extracellular vesicles.

Preconditioning of MSCs for Acute Neurological Conditions: From Cellular to Functional Impact-A Systematic Review

This systematic review aims to gather evidence on the mechanisms triggered by diverse preconditioning strategies for mesenchymal stem cells (MSCs) and their impact on their potential to treat ischemic and traumatic injuries affecting the nervous system. The 52 studies included in this review report nine different types of preconditioning, namely, manipulation of oxygen pressure, exposure to chemical substances, lesion mediators or inflammatory factors, usage of ultrasound, magnetic fields or biomechanical forces, and culture in scaffolds or 3D cultures. All these preconditioning strategies were reported to interfere with cellular pathways that influence MSCs' survival and migration, alter MSCs' phenotype, and modulate the secretome and proteome of these cells, among others. The effects on MSCs' phenotype and characteristics influenced MSCs' performance in models of injury, namely by increasing the homing and integration of the cells in the lesioned area and inducing the secretion of growth factors and cytokines. The administration of preconditioned MSCs promoted tissue regeneration, reduced neuroinflammation, and increased angiogenesis and myelinization in rodent models of stroke, traumatic brain injury, and spinal cord injury. These effects were also translated into improved cognitive and motor functions, suggesting an increased therapeutic potential of MSCs after preconditioning. Importantly, none of the studies reported adverse effects or less therapeutic potential with these strategies. Overall, we can conclude that all the preconditioning strategies included in this review can stimulate pathways that relate to the therapeutic effects of MSCs. Thus, it would be interesting to explore whether combining different preconditioning strategies can further boost the reparative effects of MSCs, solving some limitations of MSCs' therapy, namely donor-associated variability.

Effect of human umbilical cord blood-mesenchymal stem cells on cisplatin-induced nephrotoxicity in rats

BACKGROUND

Cisplatin-containing regimen is an effective treatment for several malignancies. However, cisplatin is an important cause of nephrotoxicity. So, many trials were performed to transplant stem cells systemically or locally to control cisplatin-induced nephrotoxicity. Stem cell therapeutic effect may be dependent on the regulation of inflammation and oxidant stress.

AIM

To investigate the effect of human umbilical cord blood-mesenchymal stem cells (hUCB-MSCs) on the histological structure, the oxidant stress, and the inflammatory gene expression in an experimental model of cisplatin-induced nephrotoxicity in rats.

METHOD

The rats were divided into 6 equal groups (each of 10 rats): Group I included normal rats that received no treatment. Group II included healthy rats that received IV hUCB-MSCs. Group III included untreated cisplatin-induced nephrotoxic rats. Group IV included cisplatin-induced nephrotoxic rats that received magnesium (Mg) injections after injury. Group V was injected with hUCB-MSCs after injury. Group VI received both Mg and hUCB-MSCs after injury. In tissue homogenates, reduced glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA) activities were measured. Quantitative real-time-polymerase chain reaction (qRT-PCR) was performed to assess iNOS, TLR4, and NF-kB gene expression. Hematoxylin and eosin (H&E) staining was performed to study the histological structure of the kidney. Immunohistochemical staining of iNOS and NF-κB was performed, as well.

RESULTS

Disturbed kidney functions, oxidative status, and histological structure were seen in the rats that received cisplatin. Treated groups showed improvements in kidney functions, oxidative status, and histological structure, particularly in the combined treatment group.

CONCLUSION

In the cisplatin-induced nephrotoxicity model, hUCB-MSCs could improve the functional and morphological kidney structure by modulation of oxidative and inflammatory status.

Human umbilical cord mesenchymal stem cells-derived exosomal circDLGAP4 promotes angiogenesis after cerebral ischemia-reperfusion injury by regulating miR-320/KLF5 axis

Accumulating evidence suggests that human umbilical cord mesenchymal stem cell-derived exosomes (hUC-MSCs-Exos) are a promising therapeutic strategy for cerebral ischemia-reperfusion injury (CIRI). However, the underlying mechanism remains unclear. hUC-MSCs-Exos were identified by electron microscopy, NTA, and Western blotting. In the hypoxia/reoxygenation (H/R) cell model, human brain microvascular endothelial cells (HBMECs) were cocultured with hUC-MSCs-Exos. Then, cell viability, migration, apoptosis, and tube formation were measured by MTT, flow cytometry, transwell, and tube formation assays. RT-qPCR and Western blotting were used to detect the changes in RNA and protein. RNA pull-down and dual luciferase reporter assays confirmed the relationship between circDLGAP4, miR-320, and KLF5. Ischemia-reperfusion (I/R) rat model was established for in vivo experiments. hUC-MSCs-Exos increased the expression levels of circDLGAP4 and KLF5 but decreased miR-320 in H/R-treated HBMECs by transferring exosomal circDLGAP4. Knockdown of circDLGAP4 in hUC-MSCs-Exos reversed the promoting effects of hUC-MSCs-Exos on cell viability, migration, and tube formation in H/R-treated HBMECs in vitro and also abolished the protective effects of hUC-MSCs-Exos on cerebrovascular injury in I/R rats. Mechanistically, exosomal circDLGAP4 negatively regulated miR-320 in HBMECs, which directly bound to KLF5. In addition, the downregulation of miR-320 could reverse the regulatory effect of exosomal shcircDLGAL5 in H/R-treated HBMECs by upregulating KLF5. hUC-MSCs-Exos-derived circDLGAP4 reduced cerebrovascular injury by regulating miR-320/KLF5 signaling. These results provide a stem cell-based approach to treat CIRI.

Dose-dependent benefits of iron-magnetic nanoparticle-coated human umbilical-derived mesenchymal stem cell treatment in rat intracranial hemorrhage model

BACKGROUND

This study tested whether two doses of human umbilical-derived mesenchymal stem cells (hUC-MSCs) were superior to one dose for protecting the brain against intracranial hemorrhage (ICH) induced by intracranial injection collagenase and the capacity of ironic-magnetic-nanoparticles (Ir-MNa) coated hUC-MSCs tracked by MRI.

METHODS AND RESULTS

Adult male SD rats (n = 40) were equally categorized into group 1 (sham-operated-control), group 2 (ICH), group 3 [ICH + Ir-MNa-coated hUC-MSCs/1.2 × 10⁶ cells with an extracorporeal magnet over rat head (eCMag)/administered by left internal carotid artery (LICA) at post-3 h ICH], and group 4 (ICH + Ir-MNa-coated hUC-MSCs/1.2 × 10⁶ cells with an eCMag/administered post-3 h ICH by LICA and 24 h by IV) and euthanized by day 28. The result showed that by day 28 after ICH induction the neurological function was severely impaired in group 2 than in group 1 that was significantly improved in group 3 and further significantly improved in group 4, whereas ICH volume exhibited an opposite pattern of neurological impairment among the groups (all p < 0.0001). Brain MRI demonstrated that by 4 h after ICH, Ir-MNa-coated hUC-MSCs were abundantly identified in ischemic area in group 4. The protein expressions of inflammatory (TNF-α/MMP-9/IL-1ß/iNOS)/oxidative-stress (NOX-1/NOX-2/oxidized protein)/apoptotic (caspase-3/mitochondrial Bax/PARP)/fibrotic (Smad3/TGF-ß)/mitochondrial-damaged (cytosolic-cytochrome-C) biomarkers displayed an identical pattern of neurological impairment among the groups (all p < 0.0001). The cellular expressions of inflammation (CD68+/CD11b+)/brain edema (AQP4+) biomarkers exhibited an identical pattern, whereas the neuronal-myelin (Doublecortin+/NeuN/nestin) biomarkers displayed an opposite pattern of neurological impairment (all p < 0.0001).

CONCLUSION

Two doses of hUC-MSCs were superior to just one dose for protecting the brain against ICH-induced damage and Ir-MNa-coated hUC-MSCs offered a well adopted method for tracking hUC-MSCs homing into the brain.

Intranasal application of stem cells and their derivatives as a new hope in the treatment of cerebral hypoxia/ischemia: a review

Intranasal delivery of stem cells and conditioned medium to target the brain has attracted major interest in the field of regenerative medicine. In pre-clinical investigations during the last ten years, several research groups focused on this strategy to treat cerebral hypoxia/ischemia in neonates as well as adults. In this review, we discuss the curative potential of stem cells, stem cell derivatives, and their delivery route via intranasal application to the hypoxic/ischemic brain. After intranasal application, stem cells migrate from the nasal cavity to the injured area and exert therapeutic effects by reducing brain tissue loss, enhancing endogenous neurogenesis, and modulating cerebral inflammation that leads to functional improvements. However, application of this administration route for delivering stem cells and/or therapeutic substances to the damaged sites requires further optimization to translate the findings of animal experiments to clinical trials.

The Beneficial Potential of Genetically Modified Stem Cells in the Treatment of Stroke: a Review

The last two decades have witnessed a surge in investigations proposing stem cells as a promising strategy to treat stroke. Since growth factor release is considered as one of the most important aspects of cell-based therapy, stem cells over-expressing growth factors are hypothesized to yield higher levels of therapeutic efficiency. In pre-clinical studies of the last 15 years that were investigating the efficiency of stem cell therapy for stroke, a variety of stem cell types were genetically modified to over-express various factors. In this review we summarize the current knowledge on the therapeutic efficiency of stem cell-derived growth factors, encompassing techniques employed and time points to evaluate. In addition, we discuss several types of stem cells, including the recently developed model of epidermal neural crest stem cells, and genetically modified stem cells over-expressing specific factors, which could elevate the restorative potential of naive stem cells. The restorative potential is based on enhanced survival/differentiation potential of transplanted cells, apoptosis inhibition, infarct volume reduction, neovascularization or functional improvement. Since the majority of studies have focused on the short-term curative effects of genetically engineered stem cells, we emphasize the need to address their long-term impact.

Human Umbilical Cord-Derived Mesenchymal Stem Cell Therapy Effectively Protected the Brain Architecture and Neurological Function in Rat After Acute Traumatic Brain Injury

Intracranial hemorrhage from stroke and head trauma elicits a cascade of inflammatory and immune reactions detrimental to neurological integrity and function at cellular and molecular levels. This study tested the hypothesis that human umbilical cord–derived mesenchymal stem cell (HUCDMSC) therapy effectively protected the brain integrity and neurological function in rat after acute traumatic brain injury (TBI). Adult male Sprague-Dawley rats (n = 30) were equally divided into group 1 (sham-operated control), group 2 (TBI), and group 3 [TBI + HUCDMSC (1.2 × 10⁶ cells/intravenous injection at 3 h after TBI)] and euthanized by day 28 after TBI procedure. The results of corner test and inclined plane test showed the neurological function was significantly progressively improved from days 3, 7, 14, and 28 in groups 1 and 3 than in group 2, and group 1 than in group 3 (all P < 0.001). By day 28, brain magnetic resonance imaging brain ischemic volume was significantly increased in group 2 than in group 3 (P < 0.001). The protein expressions of apoptosis [mitochondrial-bax positive cells (Bax)/cleaved-caspase3/cleaved-poly(adenosine diphosphate (ADP)-ribose) polymerase], fibrosis (Smad3 positive cells (Smad3)/transforming growth factor-β), oxidative stress (NADPH Oxidase 1 (NOX-1)/NADPH Oxidase 2 (NOX-2)/oxidized-protein/cytochrome b-245 alpha chain (p22phox)), and brain-edema/deoxyribonucleic acid (DNA)–damaged biomarkers (Aquaporin-4/gamma H2A histone family member X ( (γ-H2AX)) displayed an identical pattern to neurological function among the three groups (all P < 0.0001), whereas the protein expressions of angiogenesis biomarkers (vascular endothelial growth factor/stromal cell–derived factor-1α/C-X-C chemokine receptor type 4 (CXCR4)) significantly increased from groups 1 to 3 (all P < 0.0001). The cellular expressions of inflammatory biomarkers (cluster of differentiation 14 (+) cells (CD14+)/glial fibrillary acidic protein positive cells (GFAP+)/ a member of a new family of EGF-TM7 molecules positive cells (F4/80+)) and DNA-damaged parameter (γ-H2AX) exhibited an identical pattern, whereas cellular expressions of neural integrity (hexaribonucleotide Binding Protein-3 positive cells (NeuN+)/nestin+/doublecortin+) exhibited an opposite pattern of neurological function among the three groups (all P < 0.0001). Xenogeneic HUCDMSC therapy was safe and it significantly preserved neurological function and brain architecture in rat after TBI.

Progress in Mesenchymal Stem Cell Therapy for Ischemic Stroke

Ischemic stroke (IS) is a serious cerebrovascular disease with high morbidity and disability worldwide. Despite the great efforts that have been made, the prognosis of patients with IS remains unsatisfactory. Notably, recent studies indicated that mesenchymal stem cell (MSCs) therapy is becoming a novel research hotspot with large potential in treating multiple human diseases including IS. The current article is aimed at reviewing the progress of MSC treatment on IS. The mechanism of MSCs in the treatment of IS involved with immune regulation, neuroprotection, angiogenesis, and neural circuit reconstruction. In addition, nutritional cytokines, mitochondria, and extracellular vesicles (EVs) may be the main mediators of the therapeutic effect of MSCs. Transplantation of MSCs-derived EVs (MSCs-EVs) affords a better neuroprotective against IS when compared with transplantation of MSCs alone. MSC therapy can prolong the treatment time window of ischemic stroke, and early administration within 7 days after stroke may be the best treatment opportunity. The deliver routine consists of intraventricular, intravascular, intranasal, and intraperitoneal. Furthermore, several methods such as hypoxic preconditioning and gene technology could increase the homing and survival ability of MSCs after transplantation. In addition, MSCs combined with some drugs or physical therapy measures also show better neurological improvement. These data supported the notion that MSC therapy might be a promising therapeutic strategy for IS. And the application of new technology will promote MSC therapy of IS.

Nitrogen-doped carbon nanocages and human umbilical cord mesenchymal stem cells cooperatively inhibit neuroinflammation and protect against ischemic stroke

AIMS

This study aimed to explore the synergistic effects of nitrogen-doped carbon nanocages (NCNCs) and human umbilical cord mesenchymal stem cells (HUC-MSCs) on ischemic stroke and investigate the potential underlying mechanisms.

MAIN METHODS

The properties of NCNCs were analyzed by transmission electron microscopy, and the markers of HUC-MSCs were detected by flow cytometry. The cell toxicity of NCNCs was evaluated by MTT. Mice were induced cerebral infarction by transient middle cerebral artery occlusion (MCAO). NCNCs or HUC-MSCs or HUC-MSCs-NCNCs were intravenously injected thirty minutes after reperfusion. The infarct volume was examined by 2,3,5-triphenyltetrazolium chloride (TTC) staining, and behavior tests were evaluated by the modified Neurological Severity Score (mNSS) and rotarod test. The mRNA levels of TNF-α and IL-10 were detected by real-time PCR. The protein levels of TNF-α stimulated gene/protein 6 (TSG-6) and prostaglandin 2 (PGE2) were detected by ELISA. The microglia markers (CD86 and CD206) and the protein levels of TNF-α and IL-10 were examined by flow cytometry. The protein levels of Iba1 and CD16 were determined by immunostaining.

KEY FINDINGS

NCNCs enhanced the therapeutic effects of HUC-MSCs on MCAO mice, including reducing infarct volume, improving behavior scores and inhibiting inflammation response. In addition, NCNCs and HUC-MSCs cooperatively inhibit the mRNA and protein levels of TNF-α, and increased the mRNA and protein levels of IL-10 and protein levels of PGE2 and TSG-6 in LPS-treated microglia. Furthermore, NCNCs exerted synergistic effects with HUC-MSCs on remodeling microglia polarization.

SIGNIFICANCE

NCNCs enhance the therapeutic effects of HUC-MSCs on cerebral infarction in a mouse MCAO model, and inhibit the microglia reactivation and neuroinflammation, which indicates it as a potential treatment for ischemic stroke.

Extracellular vesicles in mesenchymal stromal cells: A novel therapeutic strategy for stroke

A stroke is a focal cerebral insult that frequently causes severe neurological deficit and mortality. Recent studies have demonstrated that multipotent mesenchymal stromal cells (MSCs) hold great promise for neurovascular remodeling and neurological function recovery following a stroke. Rather than a direct replacement of parenchymal brain cells, the therapeutic mechanism of MSCs is suggested to be the secretion of soluble factors. Specifically, emerging data described MSCs as being able to release extracellular vesicles (EVs), which contain a variety of cargo including proteins, lipids, DNA and various RNA species. The released EVs can target neurocytes and vascular cells and modify the cell's functions by delivering the cargo, which are considered to mediate the neural restoration effects of MSCs. Therefore, EVs may be developed as a novel cell-free therapy for neurological disorders. In the present review, the current advances regarding the components, functions and therapeutic potential of EVs are summarized and the use of MSC-derived EVs as a promising approach in the treatment of stroke are highlighted.

Mesenchymal stromal cells from umbilical cord Wharton's jelly trigger oligodendroglial differentiation in neural progenitor cells through cell-to-cell contact

BACKGROUND AIMS

Wharton's jelly mesenchymal stromal cells (WJ-MSCs) might be ideal candidates to treat perinatal brain damage. Their secretome has been shown to have beneficial effects on neuroregeneration, in part through interaction with neural progenitor cells (NPCs). However, it remains unclear whether cell-to-cell contact decisively contributes to this positive effect. The objective of this study was to elucidate the mechanism through which differentiation in NPCs is triggered after exposure to WJ-MSCs. Furthermore, given that WJ-MSCs can be derived from term (tWJ-MSCs) or preterm (ptWJ-MSCs) deliveries and that WJ-MSCs might be used for transplantations independent of gestational age, the influence of tWJ-MSCs versus ptWJ-MSCs on the differentiation capacities of NPCs was studied.

METHODS

The effect of tWJ-MSCs and ptWJ-MSCs on the expression of neuroglial markers in NPCs was assessed in co-culture (CC), conditioned medium (CM) or transwell CC experiments by immunocytochemistry, real-time polymerase chain reaction and Western blot. Additionally, mass spectrometry was used to study their secretomes.

RESULTS

NPCs showed an increased expression of glial markers after CC with WJ-MSCs or exposure to WJ-MSC-CMs. CC had a more prominent effect on the expression of glial markers compared with CM or transwell CCs. tWJ-MSCs more strongly induced the expression of mature oligodendroglial markers compared with ptWJ-MSCs. A possible role in enhancing this maturation could be attributed to the laminin α2-subunit.

CONCLUSIONS

Cell-to-cell contact between WJ-MSCs and NPCs induces oligodendrogenesis on NPCs, whereas trophic factor secretion is sufficient to promote astrogenesis. Thus, transplanting WJ-MSCs may promote endogenous neuroregeneration in perinatal brain damage.

Proteomic Analysis of the Peri-Infarct Area after Human Umbilical Cord Mesenchymal Stem Cell Transplantation in Experimental Stroke

Among various therapeutic approaches for stroke, treatment with human umbilical cord mesenchymal stem cells (hUC-MSCs) has acquired some promising results. However, the underlying mechanisms remain unclear. We analyzed the protein expression spectrum of the cortical peri-infarction region after ischemic stroke followed by treatment with hUC-MSCs, and found 16 proteins expressed differentially between groups treated with or without hUC-MSCs. These proteins were further determined by Gene Ontology term analysis and network with CD200-CD200R1, CCL21-CXCR3 and transcription factors. Three of them: Abca13, Grb2 and Ptgds were verified by qPCR and ELISA. We found the protein level of Abca13 and the mRNA level of Grb2 consistent with results from the proteomic analysis. Finally, the function of these proteins was described and the potential proteins that deserve to be further studied was also highlighted. Our data may provide possible underlying mechanisms for the treatment of stroke using hUC-MSCs.

The potential use of mesenchymal stem cells in stroke therapy--From bench to bedside

Stroke is the second main cause of morbidity and mortality worldwide. The rationale for the use of mesenchymal stem cells (MSCs) in stroke is based on the capacity of MSCs to secrete a large variety of bioactive molecules such as growth factors, cytokines and chemokines leading to reduction of inflammation, increased neurogenesis from the germinative niches of central nervous system, increased angiogenesis, effects on astrocytes, oligodendrocytes and axons. This review presents the data derived from experimental studies and the evidence available from clinical trials about the use of MSCs in stroke therapy.