Introduction to cellular therapy: the next frontier for stroke therapeutics

Lipid Microcapsules Promoted Neural Stem Cell Survival in the Infarcted Area of Mice with Ischemic Stroke by Inducing Autophagy

Intracerebral transplantation of neural stem cells (NSCs) for ischemic stroke treatment has been demonstrated to be inefficient, with only <5% of delivered cells being retained. Microcapsules may be a good carrier for NSC delivery; however, the current microcapsules do not fully meet the demands for cell survival after transplantation. In the present study, we designed a strategy for the encapsulation of NSCs in a novel lipid-alginate (L-A) microcapsule based on a two-step method. The protective effect of a L-A microcapsule on oxygen-glucose deprivation (OGD) was investigated by using the CCK8 test, the LDH release test, and flow cytometry. Mechanisms underlying the prosurvival effect were investigated by detecting autophagy markers like P62, LC3-I, and LC3-II, and autophagy flux analysis was also performed. Lastly, the ability of the L-A microcapsule to support NSCs delivery for ischemic stroke was investigated in the middle cerebral artery occlusion (MCAO) model. We found that L-A microcapsules exerted a good protective effect against OGD compared with control and alginate microcapsules. The L-A microcapsules were found to promote cell survival by not only providing a "physical" barrier but also altering autophagy markers like P62 and LC3-II, which enhanced autophagy flux. This novel microcapsule was confirmed to be suitable for NSC delivery in vivo, which alleviated transplanted NSC apoptosis, reduced the infarct volume, decreased brain edema, improved neurological deficit scores, and lastly, improved survival rate. The findings of this study may provide a new method for stem cell delivery, raising the prospect that intracerebral cell transplantation may be used to treat, for instance, ischemic stroke, traumatic brain injury, and so on.

Fracture shortly before stroke in mice leads to hippocampus inflammation and long-lasting memory dysfunction

Cognitive impairment occurs in stroke and hip fracture patients. In mice, bone fracture (BF) exacerbates stroke-related neuronal damage and sensorimotor dysfunction. We hypothesize that BF exacerbates post-stroke cognitive impairment. Adult mice were randomly assigned into BF, stroke, BF+stroke (BF 6 h before stroke), and control (sham operated) groups. Memory function was evaluated weekly for eight weeks by Y maze test and at eight weeks post-surgeries by novel object recognition (NOR) test. The neuronal damage and inflammation in hippocampus were analyzed three days and eight weeks after the surgeries. In Y maze test, BF+stroke mice started making fewer alternations than controls two weeks after the surgeries. Significant difference between BF+stroke and stroke groups started at five weeks post-injury and continued to the end of the experiment. In NOR test, BF+stroke group spent less time on novel objective than that of other groups. Cx3cr1⁺ cells and CD68⁺ cells accumulated in the stratum lacunosum moleculare (SLM) on the ipsilateral side of stroke injury in stroke and BF+stroke mice. BF+stroke mice had a higher ratio of ipsilateral/contralateral Cx3cr1⁺ cell-density than that of stroke mice. Therefore, BF shortly before stroke exacerbates hippocampal inflammation and causes long-lasting memory dysfunction.

Combinatorial Treatment Using Umbilical Cord Perivascular Cells and Aβ Clearance Rescues Vascular Function Following Transient Hypertension in a Rat Model of Alzheimer Disease

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Transient hypertension is a risk factor for Alzheimer disease (AD), but the effects of this interaction on brain vasculature are understudied. Addressing vascular pathology is a promising avenue to potentiate the efficacy of treatments for AD. We used arterial spin labeling magnetic resonance imaging to longitudinally assess brain vascular function and immunohistopathology to examine cerebrovascular remodeling and amyloid load. Hypertension was induced for 1 month by administration of l-N^G-nitroarginine-methyl-ester in TgF344-AD rats at the prodromal stage. Following hypertension, nontransgenic rats showed transient cerebrovascular changes, whereas TgF344-AD animals exhibited sustained alterations in cerebrovascular function. Human umbilical cord perivascular cells in combination with scyllo-inositol, an inhibitor of Aβ oligomerization, resulted in normalization of hippocampal vascular function and remodeling, in contrast to either treatment alone. Prodromal stage hypertension exacerbates latter AD pathology, and the combination of human umbilical cord perivascular cells with amyloid clearance promotes cerebrovascular functional recovery.

De Novo Arteriovenous Malformation Growth Secondary to Implantation of Genetically Modified Allogeneic Mesenchymal Stem Cells in the Brain

BACKGROUND AND IMPORTANCE

Local biological drug delivery in the brain is an innovative field of medicine that developed rapidly in recent years. Our report illustrates a unique case of de novo development of a cerebral arteriovenous malformation (AVM) after implantation of genetically modified allogeneic mesenchymal stem cells in the brain.

CLINICAL PRESENTATION

A 50-year-old man was included in a prospective clinical study (study ID number CM GLP-1/01, 2007-004516-31) investigating a novel neuroprotective approach in stroke patients to prevent perihematomal neuronal damage. In this study, alginate microcapsules containing genetically modified allogeneic mesenchymal stem cells producing the neuroprotective glucagon-like peptide-1 (GLP-1) were implanted. Three years later, the patient presented with aphasia and a focal seizure due to a new left frontal intracerebral hemorrhage. Angiography revealed a de novo left frontal AVM.

CONCLUSION

The development of an AVM within a period of 3 years after implantation of the glucagon-like peptide-1-secreting mesenchymal stem cells suggests a possible relationship. This case exemplifies that further investigations are necessary to assess the safety of genetically modified cell lines for local biological drug delivery in the brain.

Stem cell therapy in intracerebral hemorrhage rat model

Intracerebral hemorrhage (ICH) is a very complex pathology, with many different not fully elucidated etiologies and prognostics. It is the most severe subtype of stroke, with high mortality and morbidity rates. Unfortunately, despite the numerous promising preclinical assays including neuroprotective, anti-hypertensive, and anti-inflammatory drugs, to this moment only symptomatic treatments are available, motivating the search for new alternatives. In this context, stem cell therapy emerged as a promising tool. However, more than a decade has passed, and there is still much to be learned not only about stem cells, but also about ICH itself, and how these two pieces come together. To date, rats have been the most widely used animal model in this research field, and there is much more to be learned from and about them. In this review, we first summarize ICH epidemiology, risk factors, and pathophysiology. We then present different methods utilized to induce ICH in rats, and examine how accurately they represent the human disease. Next, we discuss the different types of stem cells used in previous ICH studies, also taking into account the tested transplantation sites. Finally, we summarize what has been achieved in assays with stem cells in rat models of ICH, and point out some relevant issues where attention must be given in future efforts.

Calcium-sensing receptor (CaSR) as a novel target for ischemic neuroprotection

Object

Ischemic brain injury is the leading cause for death and long-term disability in patients who suffer cardiac arrest and embolic stroke. Excitotoxicity and subsequent Ca²⁺-overload lead to ischemic neuron death. We explore a novel mechanism concerning the role of the excitatory extracellular calcium-sensing receptor (CaSR) in the induction of ischemic brain injury.

Method

Mice were exposed to forebrain ischemia and the actions of CaSR were determined after its genes were ablated specifically in hippocampal neurons or its activities were inhibited pharmacologically. Since the CaSR forms a heteromeric complex with the inhibitory type B γ-aminobutyric acid receptor 1 (GABA_BR1), we compared neuronal responses to ischemia in mice deficient in CaSR, GABA_BR1, or both, and in mice injected locally or systemically with a specific CaSR antagonist (or calcilytic) in the presence or absence of a GABA_BR1 agonist (baclofen).

Results

Both global and focal brain ischemia led to CaSR overexpression and GABA_BR1 downregulation in injured neurons. Genetic ablation of Casr genes or blocking CaSR activities by calcilytics rendered robust neuroprotection and preserved learning and memory functions in ischemic mice, partly by restoring GABA_BR1 expression. Concurrent ablation of Gabbr1 gene blocked the neuroprotection caused by the Casr gene knockout. Coinjection of calcilytics with baclofen synergistically enhanced neuroprotection. This combined therapy remained robust when given 6 h after ischemia.

Interpretation

Our study demonstrates a novel receptor interaction, which contributes to ischemic neuron death through CaSR upregulation and GABA_BR1 downregulation, and feasibility of neuroprotection by concurrently targeting these two receptors.

Growth hormone (GH) and brain trauma

Growth hormone (GH) is a pleiotropic hormone with known neurotrophic effects. We aimed to study whether GH administration might be useful together with rehabilitation in the recovery of TBI patients. 13 TBI patients (8 M, 5 F; age: 6-53 years old) were studied. Time after TBI: 2.5 months to 11 years; 5 patients showed acquired GH-deficiency (GHD). Disabilities observed: cognitive disorders; motor plegias; neurogenic dysphagia (n=5), vegetative coma (n=2) and amaurosis (n=1). All but one TBI patient followed intense rehabilitation for years. Treatment consisted of GH administration (maximal dose 1 mg/day, 5 days/week, resting 15-days every 2-months, until a maximum of 8 months) and clinical rehabilitation according to the individual needs (3-4 h/day, 5 days/week, during 6-12 months). Informed consent was obtained before commencing GH administration. GH significantly increased plasma IGF-1 values (ng.mL(-1)) in both GHD and no GHD patients, being then similar between both groups (GHD: 275.6±35.6 [p<0.01 vs. baseline], no GHD: 270.2±64 [p<0.05 vs. baseline]). In all the cases clear significant improvements were observed during and at the end of the combined treatment. Cognitive improvements appeared earlier and were more important than motor improvements. Swallowing improved significantly in all TBI patients with neurogenic dysphagia (2 of them in a vegetative state). Visual performance was ameliorated in the patient with amaurosis. No undesirable side-effects were observed. Our data indicate that GH can be combined with rehabilitation for improving disabilities in TBI patients, regardless of whether or not they are GHD.

Clinical translation of stem cell therapy in traumatic brain injury: the potential of encapsulated mesenchymal cell biodelivery of glucagon-like peptide-1

Traumatic brain injury remains a major cause of death and disability; it is estimated that annually 10 million people are affected. Preclinical studies have shown the potential therapeutic value of stem cell therapies. Neuroprotective as well as regenerative properties of stem cells have been suggested to be the mechanism of action in preclinical studies. However, up to now stem cell therapy has not been studied extensively in clinical trials. This article summarizes the current experimental evidence and points out hurdles for clinical application. Focusing on a cell therapy in the acute stage of head injury, the potential of encapsulated cell biodelivery as a novel cell-therapeutic approach will also be discussed.

Cerebral transplantation of encapsulated mesenchymal stem cells improves cellular pathology after experimental traumatic brain injury

PURPOSE

"Naked" human mesenchymal stem cells (MSC) are neuro-protective in experimental brain injury (TBI). In a controlled cortical impact (CCI) rat model, we investigated whether encapsulated MSC (eMSC) act similarly, and whether efficacy is augmented using cells transfected to produce the neuro-protective substance glucagon-like peptide-1 (GLP-1).

METHODS

Thirty two Sprague-Dawley rats were randomized to five groups: controls (no CCI), CCI-only, CCI+eMSC, CCI+GLP-1 eMSC, and CCI+empty capsules. On day 14, cisternal cerebro-spinal fluid (CSF) was sampled for measurement of GLP-1 concentration. Brains were immuno-histochemically assessed using specific antibody staining for NeuN, MAP-2 and GFAP. In another nine healthy rats, in vitro.

RESULTS

GLP-1 production rates were measured from cells explanted after 2, 7 and 14 days. GLP-1 production rate in transfected cells, before implantation, was 7.03 fmol/capsule/h. Cells were still secreting GLP-1 at a rate of 3.68+/-0.49, 2.85+/-0.45 and 3.53+/-0.55 after 2, 7 and 14 days, respectively. In both of the stem cell treated CCI groups, hippocampal cell loss was reduced, along with an attenuation of cortical neuronal and glial abnormalities, as measured by MAP-2 and GFAP expression. The effects were more pronounced in animals treated with GLP-1 secreting eMSC. This group displayed an increased CSF level of GLP-1 (17.3+/-3.4pM).

CONCLUSIONS

Hippocampal neuronal cell loss, and cortical glial and neuronal cyto-skeletal abnormalities, after CCI are reduced following transplantation of encapsulated eMSC. These effects were augmented by GLP-1 transfected eMSC.