Mesenchymal stem cell therapy of brain ischemic stroke in rats

Mesenchymal stem cell (MSCs)-based therapy is a promising attempt to improve the recovery after stroke. Our experiments were carried out on inbred Wistar-Kyoto rats. MSCs were isolated, expanded in culture, and labeled with vital fluorescent dye PKH-26. Animals were subjected to middle cerebral artery occlusion (MCAO). After three days, MCAO 5 × 10⁶ isolated MSCs were injected into the tail vein of the experimental rats. The control animal group received PBS injections (negative control). Therapy results were evaluated by the following parameters: behavioral and neurological testing, the inured brain areas, damaged brain structures, neuron state, and vessel quantity in the region close to with necrosis zone. It was shown that control animals (PBS injection) did not return to their initial behavioral and neurological state within 6 weeks, while the experimental animals (MSCs injection), within 2–3 weeks after MCAO, had parameters like intact rats. The size of the damaged region in the control group was larger than in the experimental group by a factor of approximately 1.3. The damage in MSC-treated rats was limited to the neocortex; caudate nucleus, capsula externa and piriform cortex remained uninjured. The small vessel quantity in the “border” regions was twice as high as compared to the control group and approximately equal to the number of vessels in an intact brain. For the first time, we demonstrated that the vessel quantity in the neocortex and caudate nucleus of the contralateral hemisphere after MSC transplantation was twice as high as in control rats. It is concluded that the MSC transplantation exerts a beneficial influence upon the brain tissue reparation after stroke.     

Mesenchymal stem cells transplantation influences upon dynamics of morphological changes in rat brain after stroke

Study of dynamic morphological changes if the brain after ischemic stroke is an important phase of pre-clinical trial of mesenchymal stem cell (MSC) therapy for this widespread disease. Experoments were carried out in inbred Wistar-Kyoto rats. MSCs were isolated, expanded in culture and labeled with vital fluorescent dye PKH26. Animals were subjected to middle cerebral artery occlusion (MCAO) followed by injection of 5 x 10(6) rat MSCs into the tail vein on the day of MCAO. Control group of animals received PBS injection (negative control). Animals were sacrificed in 1, 2, 3 and 5 days and in 1, 2, 4 and 6 weeks after operation. MSCs were revealed in the brain on the third day transplantation. They distributed around brain vessels in both the ipsilateral and contralateral hemispheres. This pattern of distribution remained unchanged during 6 weeks of observation. It was demonstrated that inflammation process and scar formation in the experimental group progressed 25-30 % faster than in the control group. MSC transplantation stimulated endogenous stem cell proliferation on the subependimal zone of lateral ventricles (subventrecular zone). What is more, MSC injection showed neuroprotective effect: almost all penumbra neurons in animals treated with cell therapy retained their normal structure, whereas in animals of control group penumbra neurons died or had signs of serious damage.     

Neural stem cell transplantation therapy for brain ischemic stroke: Review and perspectives

Brain ischemic stroke is one of the most common causes of death and disability, currently has no efficient therapeutic strategy in clinic. Due to irreversible functional neurons loss and neural tissue injury, stem cell transplantation may be the most promising treatment approach. Neural stem cells (NSCs) as the special type of stem cells only exist in the nervous system, can differentiate into neurons, astrocytes, and oligodendrocytes, and have the abilities to compensate insufficient endogenous nerve cells and improve the inflammatory microenvironment of cell survival. In this review, we focused on the important role of NSCs therapy for brain ischemic stroke, mainly introduced the methods of optimizing the therapeutic efficacy of NSC transplantation, such as transfection and overexpression of specific genes, pretreatment of NSCs with inflammatory factors, and co-transplantation with cytokines. Next, we discussed the potential problems of NSC transplantation which seriously limited their rapid clinical transformation and application. Finally, we expected a new research topic in the field of stem cell research. Based on the bystander effect, exosomes derived from NSCs can overcome many of the risks and difficulties associated with cell therapy. Thus, as natural seed resource of nervous system, NSCs-based cell-free treatment is a newly therapy strategy, will play more important role in treating ischemic stroke in the future.     

Mesenchymal stem cells in ischemic tissue regeneration

Diseases caused by ischemia are one of the leading causes of death in the world. Current therapies for treating acute myocardial infarction, ischemic stroke, and critical limb ischemia do not complete recovery. Regenerative therapies opens new therapeutic strategy in the treatment of ischemic disorders. Mesenchymal stem cells(MSCs) are the most promising option in the field of cell-based therapies, due to their secretory and immunomodulatory abilities, that contribute to ease inflammation and pr...     

Mesenchymal stem cells: therapeutic outlook for stroke

Adult bone marrow-derived mesenchymal stem cells (MSCs) display a spectrum of functional properties. Transplantation of these cells improves clinical outcome in models of cerebral ischemia and spinal cord injury via mechanisms that may include replacement of damaged cells, neuroprotective effects, induction of axonal sprouting, and neovascularization. Therapeutic effects have been reported in animal models of stroke after intravenous delivery of MSCs, including those derived from adult human bone marrow. Initial clinical studies on intravenously delivered MSCs have now been completed in human subjects with stroke. Here, we review the reparative and protective properties of transplanted MSCs in stroke models, describe initial human studies on intravenous MSC delivery in stroke, and provide a perspective on prospects for future progress with MSCs.     

Mesenchymal stem cell therapy to rebuild cartilage

Disorders affecting cartilage touch almost the whole population and are one of the leading causes of invalidity in adults. To repair cartilage, therapeutic approaches initially focused on the implantation of autologous chondrocytes, but this technique proved unsatisfactory because of the limited number of chondrocytes obtained at harvest. The discovery that several adult human tissues contain mesenchymal stem cells (MSCs) capable of differentiating into chondrocytes raised the possibility of injecting MSCs to repair cartilages. The important data published recently on the factors controlling chondrocyte commitment must be thoroughly considered to make further progress towards this therapeutic approach. The potential application of MSC therapy provides new hope for the development of innovative treatments for the repair of cartilage disorders.     

Effects of intranasal guanosine administration on brain function in a rat model of ischemic stroke

Ischemic stroke is a major cause of morbidity and mortality worldwide and only few affected patients are able to receive treatment, especially in developing countries. Detailed pathophysiology of brain ischemia has been extensively studied in order to discover new treatments with a broad therapeutic window and that are accessible to patients worldwide. The nucleoside guanosine (Guo) has been shown to have neuroprotective effects in animal models of brain diseases, including ischemic stroke. In a rat model of focal permanent ischemia, systemic administration of Guo was effective only when administered immediately after stroke induction. In contrast, intranasal administration of Guo (In-Guo) was effective even when the first administration was 3 h after stroke induction. In order to validate the neuroprotective effect in this larger time window and to investigate In-Guo neuroprotection under global brain dysfunction induced by ischemia, we used the model of thermocoagulation of pial vessels in Wistar rats. In our study, we have found that In-Guo administered 3 h after stroke was capable of preventing ischemia-induced dysfunction, such as bilateral suppression and synchronicity of brain oscillations and ipsilateral cell death signaling, and increased permeability of the blood-brain barrier. In addition, In-Guo had a long-lasting effect on preventing ischemia-induced motor impairment. Our data reinforce In-Guo administration as a potential new treatment for brain ischemia with a more suitable therapeutic window.

     

Comparison of mesenchymal stem cells from adipose tissue and bone marrow for ischemic stroke therapy

Background aimsTransplantation of mesenchymal stromal cells (MSC) derived from bone marrow (BM) or adipose tissue is expected to become a cell therapy for stroke. The present study compared the therapeutic potential of adipose-derived stem cells (ASC) with that of BM-derived stem cells (BMSC) in a murine stroke model.MethodsASC and BMSC were isolated from age-matched C57BL/6J mice. These MSC were analyzed for growth kinetics and their capacity to secrete trophic factors and differentiate toward neural and vascular cell lineages in vitro. For in vivo study, ASC or BMSC were administrated intravenously into recipient mice (1 × 10⁵ cells/mouse) soon after reperfusion following a 90-min middle cerebral artery occlusion. Neurologic deficits, the degree of infarction, expression of factors in the brain, and the fate of the injected cells were observed.ResultsASC showed higher proliferative activity with greater production of vascular endothelial cell growth factor (VEGF) and hepatocyte growth factor (HGF) than BMSC. Furthermore, in vitro conditions allowed ASC to differentiate into neural, glial and vascular endothelial cells. ASC administration showed remarkable attenuation of ischemic damage, although the ASC were not yet fully incorporated into the infarct area. Nonetheless, the expression of HGF and angiopoietin-1 in ischemic brain tissue was significantly increased in ASC-treated mice compared with the BMSC group.ConclusionsCompared with BMSC, ASC have great advantages for cell preparation because of easier and safer access to adipose tissue. Taken together, our findings suggest that ASC would be a more preferable source for cell therapy for brain ischemia than BMSC.     

Mesenchymal stem cells as tool for antitumor therapy

The development of antitumor preparations with low toxicity and high selectivity of action is one of the top priorities of cancer gene therapy. Mesenchymal stem cells possess natural tropism towards tumors, a property that makes it possible to use them as vehicles for the targeted delivery of therapeutic genes to tumors of various etiologies. At present, genes that encode enzymes (cytosine deaminase, thymidine kinase, carboxyl esterase), cytokines (IL-2, IL-4, IL-12, and IFN-β), and apoptosis inducing factors (TRAIL) are used as therapeutic genes. Mesenchymal stem cells, as demonstrated using experimental models of tumors of various etiologies, as well as animals with metastases in brain and lungs, are able to successfully deliver therapeutic genes into tumors and produce a significant antitumor effect. However, to effectively use this therapeutic strategy in a clinical setting, a number of technical problems must be solved.     

Long-term survival of human neural stem cells in the ischemic rat brain upon transient immunosuppression

Understanding the physiology of human neural stem cells (hNSCs) in the context of cell therapy for neurodegenerative disorders is of paramount importance, yet large-scale studies are hampered by the slow-expansion rate of these cells. To overcome this issue, we previously established immortal, non-transformed, telencephalic-diencephalic hNSCs (IhNSCs) from the fetal brain. Here, we investigated the fate of these IhNSC's immediate progeny (i.e. neural progenitors; IhNSC-Ps) upon unilateral implantation into the corpus callosum or the hippocampal fissure of adult rat brain, 3 days after global ischemic injury. One month after grafting, approximately one fifth of the IhNSC-Ps had survived and migrated through the corpus callosum, into the cortex or throughout the dentate gyrus of the hippocampus. By the fourth month, they had reached the ipsilateral subventricular zone, CA1-3 hippocampal layers and the controlateral hemisphere. Notably, these results could be accomplished using transient immunosuppression, i.e administering cyclosporine for 15 days following the ischemic event. Furthermore, a concomitant reduction of reactive microglia (Iba1+ cells) and of glial, GFAP+ cells was also observed in the ipsilateral hemisphere as compared to the controlateral one. IhNSC-Ps were not tumorigenic and, upon in vivo engraftment, underwent differentiation into GFAP+ astrocytes, and β-tubulinIII+ or MAP2+ neurons, which displayed GABAergic and GLUTAmatergic markers. Electron microscopy analysis pointed to the formation of mature synaptic contacts between host and donor-derived neurons, showing the full maturation of the IhNSC-P-derived neurons and their likely functional integration into the host tissue. Thus, IhNSC-Ps possess long-term survival and engraftment capacity upon transplantation into the globally injured ischemic brain, into which they can integrate and mature into neurons, even under mild, transient immunosuppressive conditions. Most notably, transplanted IhNSC-P can significantly dampen the inflammatory response in the lesioned host brain. This work further supports hNSCs as a reliable and safe source of cells for transplantation therapy in neurodegenerative disorders.     

Dynamics of morphological changes after transplantation of mesenchymal stem cells in rat brain provoked by stroke

The study of the dynamic of morphological changes in the brain after ischemic stroke is very important for the preclinical trial of mesenchymal stem cell (MSC) therapy for this widespread disease. Experiments were carried out in inbred Wistar-Kyoto rats. MSCs were isolated, expanded in culture, and labeled with the vital fluorescent dye PKH-26. Animals were subjected to middle cerebral artery occlusion (MCAO), followed by an injection of 5 × 10⁶ rat MSCs into the tail vein on the day of MCAO. Control group animals received PBS injection (negative control). Animals were sacrificed at 1, 2, 3, and 5 days and 1, 2, 4, and 6 weeks after the operation. MSCs were revealed in the brain on the third day after transplantation as being distributed around brain vessels both in the ipsilateral and contralateral hemispheres. This pattern of distribution remained unchanged throughout six weeks of observation. It was demonstrated that the inflammation process and scar formation in the cell therapy group were progressing at a rate 25–30% faster than in the control group. MSC transplantation stimulated endogenous stem cell proliferation in the subependimal zone of lateral ventricles (subventricular zone). In addition, MSC injection caused a neuroprotecting effect; most penumbra neurons retained their structure in cell therapy group, whereas in control group, animal penumbra neurons died or showed signs of serious damage.     

Mesenchymal stem cells: Emerging mechanisms of immunomodulation and therapy

Mesenchymal stem cells (MSCs) are a pleiotropic population of cells that are self-renewing and capable of differentiating into canonical cells of the mesenchyme, including adipocytes, chondrocytes, and osteocytes. They employ multi-faceted approaches to maintain bone marrow niche homeostasis and promote wound healing during injury. Biomedical research has long sought to exploit their pleiotropic properties as a basis for cell therapy for a variety of diseases and to facilitate hematopoietic stem cell establishment and stromal reconstruction in bone marrow transplantation. Early results demonstrated their usage as safe, and there was little host response to these cells. The discovery of their immunosuppressive functions ushered in a new interest in MSCs as a promising therapeutic tool to suppress inflammation and down-regulate pathogenic immune responses in graft-versus-host and autoimmune diseases such as multiple sclerosis, autoimmune diabetes, and rheumatoid arthritis. MSCs produce a large number of soluble and membrane-bound factors, some of which inhibit immune responses. However, the full range of MSC-mediated immune-modulation remains incompletely understood, as emerging reports also reveal that MSCs can adopt an immunogenic phenotype, stimulate immune cells, and yield seemingly contradictory results in experimental animal models of inflammatory disease. The present review describes the large body of literature that has been accumulated on the fascinating biology of MSCs and their complex effects on immune responses.     

Building a "brain attack" team to administer thrombolytic therapy for acute ischemic stroke

Before tissue plasminogen activator (tPA) was licensed for use in Canada, in February 1999, the Calgary Regional Stroke Program spearheaded the development and organization of local resources to use thrombolytic therapy in patients who had experienced acute ischemic stroke. In 1996 special permission was obtained from the Calgary Regional Health Authority to use intravenously administered tPA for acute ischemic stroke, and ethical and scientific review boards approved the protocols. After 3 years our efforts have resulted in improved patient outcomes, shorter times from symptom onset to treatment and acceptable adverse event rates. Areas for continued improvement include the door-to-needle time and broader education of the public about the symptoms of acute ischemic stroke.     

Mesenchymal stem cells effectively reduce surgically induced stenosis in rat carotids

Restenosis following vascular injury remains a pressing clinical problem. Mesenchymal stem cells (MSCs) promise as a main actor of cell-based therapeutic strategies. The possible therapeutic role of MSCs in vascular stenosis in vivo has been poorly investigated so far. We tested the effectiveness of allogenic bone marrow-derived MSCs in reduction of stenosis in a model of rat carotid arteriotomy. MSCs were expanded in vitro retaining their proliferative and differentiation potentiality. MSCs were able to differentiate into adipocyte and osteocyte mesenchymal lineage cells, retained specific antigens CD73, CD90, and CD105, expressed smooth muscle alpha-actin, were mainly in proliferative phase of cell cycle and showed limited senescence. WKY rats were submitted to carotid arteriotomy and to venous administration with 5 x 10(6) MSCs. MSCs in vivo homed in injured carotids since 3 days after arteriotomy but not in contralateral uninjured carotids. Lumen area in MSC-treated carotids was 36% greater than in control arteries (P = 0.016) and inward remodeling was limited in MSC-treated carotids (P = 0.030) 30 days after arteriotomy. MSC treatment affected the expression level of inflammation-related genes, inducing a decrease of IL-1beta and Mcp-1 and an increase of TGF-beta in injured carotids at 3 and 7 days after arteriotomy (P < 0.05). Taken together, these results indicate that allogenic MSC administration limits stenosis in injured rat carotids and plays a local immunomodulatory action.