Stem cells for neonatal stroke- the future is here

An update on stem cell therapy for stroke patients: Where are we now?

With a foundation built upon initial work from the 1980s demonstrating graft viability in cerebral ischemia, stem cell transplantation has shown immense promise in promoting survival, enhancing neuroprotection and inducing neuroregeneration, while mitigating both histological and behavioral deficits that frequently accompany ischemic stroke. These findings have led to a number of clinical trials that have thoroughly supported a strong safety profile for stem cell therapy in patients but have generated variable efficacy. As preclinical evidence continues to expand through the investigation of new cell lines and optimization of stem cell delivery, it remains critical for translational models to adhere to the protocols established through basic scientific research. With the recent shift in approach towards utilization of stem cells as a conjunctive therapy alongside standard thrombolytic treatments, key issues including timing, route of administration, and stem cell type must each be appropriately translated from the laboratory in order to resolve the question of stem cell efficacy for cerebral ischemia that ultimately will enhance therapeutics for stroke patients towards improving quality of life.

TITLE: New therapeutic approaches in pediatric diseases: Mesenchymal stromal cell and mesenchymal stromal cell-derived extracellular vesicles as new drugs

Mesenchymal Stromal Cell (MSC) clinical applications have been widely reported and their therapeutic potential has been documented in several diseases. MSCs can be isolated from several human tissues and easily expanded in vitro, they are able to differentiate in a variety of cell lineages, and they are known to interact with most immunological cells, showing immunosuppressive and tissue repair properties. Their therapeutic efficacy is closely associated with the release of bioactive molecules, namely Extracellular Vesicles (EVs), effective as their parental cells. EVs isolated from MSCs act by fusing with target cell membrane and releasing their content, showing a great potential for the treatment of injured tissues and organs, and for the modulation of the host immune system. EV-based therapies provide, as major advantages, the possibility to cross the epithelium and blood barrier and their activity is not influenced by the surrounding environment. In the present review, we deal with pre-clinical reports and clinical trials to provide data in support of MSC and EV clinical efficacy with particular focus on neonatal and pediatric diseases. Considering pre-clinical and clinical data so far available, it is likely that cell-based and cell-free therapies could become an important therapeutic approach for the treatment of several pediatric diseases.

Perinatal Stroke in Fetuses, Preterm and Term Infants

Perinatal stroke is a well-defined heterogenous group of disorders involving a focal disruption of cerebral blood flow between 20 weeks gestation and 28 days of postnatal life. The most focused lifetime risk for stroke occurs during the first week after birth. The morbidity of perinatal stroke is high, as it is the most common cause of hemiparetic cerebral palsy which results in lifelong disability that becomes more apparent throughout childhood. Perinatal strokes can be classified by the timing of diagnosis (acute or retrospective), vessel involved (arterial or venous), and underlying cause (hemorrhagic or ischemic). Perinatal stroke has primarily been reported as a disorder of term infants; however, the preterm brain possesses different vulnerabilities that predispose an infant to stroke injury both in utero and after birth. Accurate diagnosis of perinatal stroke syndromes has important implications for investigations, management, and prognosis. The classification of perinatal stroke by age at presentation (fetal, preterm neonatal, term neonatal, and infancy/childhood) is summarized in this review, and includes detailed descriptions of risk factors, diagnosis, treatment, outcomes, controversies, and resources for family support.

Mesenchymal Stem Cells for Neurological Disorders

Neurological disorders are becoming a growing burden as society ages, and there is a compelling need to address this spiraling problem. Stem cell-based regenerative medicine is becoming an increasingly attractive approach to designing therapies for such disorders. The unique characteristics of mesenchymal stem cells (MSCs) make them among the most sought after cell sources. Researchers have extensively studied the modulatory properties of MSCs and their engineering, labeling, and delivery methods to the brain. The first part of this review provides an overview of studies on the application of MSCs to various neurological diseases, including stroke, traumatic brain injury, spinal cord injury, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and other less frequently studied clinical entities. In the second part, stem cell delivery to the brain is focused. This fundamental but still understudied problem needs to be overcome to apply stem cells to brain diseases successfully. Here the value of cell engineering is also emphasized to facilitate MSC diapedesis, migration, and homing to brain areas affected by the disease to implement precision medicine paradigms into stem cell-based therapies.

White matter injury in infants with intraventricular haemorrhage: mechanisms and therapies

Intraventricular haemorrhage (IVH) continues to be a major complication of prematurity that can result in cerebral palsy and cognitive impairment in survivors. No optimal therapy exists to prevent IVH or to treat its consequences. IVH varies in severity and can present as a bleed confined to the germinal matrix, small-to-large IVH or periventricular haemorrhagic infarction. Moderate-to-severe haemorrhage dilates the ventricle and damages the periventricular white matter. This white matter injury results from a constellation of blood-induced pathological reactions, including oxidative stress, glutamate excitotoxicity, inflammation, perturbed signalling pathways and remodelling of the extracellular matrix. Potential therapies for IVH are currently undergoing investigation in preclinical models and evidence from clinical trials suggests that stem cell treatment and/or endoscopic removal of clots from the cerebral ventricles could transform the outcome of infants with IVH. This Review presents an integrated view of new insights into the mechanisms underlying white matter injury in premature infants with IVH and highlights the importance of early detection of disability and immediate intervention in optimizing the outcomes of IVH survivors.

Enhanced Mesenchymal Stromal Cells or Erythropoietin Provide Long-Term Functional Benefit After Neonatal Stroke

BACKGROUND AND PURPOSE

Perinatal stroke is a common cause of life-long neurobehavioral compromise. Mesenchymal stromal cells (MSCs) and EPO (erythropoietin) have each demonstrated short-term benefit with delayed administration after stroke, and combination therapy may provide the most benefit. The purpose of this study is to determine the long-term histological and functional efficacy of enhanced, intranasal stem cell therapy (MSC preexposed to EPO) compared with standard MSC or multidose systemic EPO.

METHODS

Transient middle cerebral artery occlusion or sham surgery was performed in postnatal day (P) 10 Sprague-Dawley rats, who were treated with single-dose intranasal MSC, MSC preexposed to EPO (MSC/EPO), multidose systemic EPO (EPO3; 1000 u/kg per dose×3 every 72 hours), or cell-conditioned media on P13 (day 3 [P13-P19] for EPO), or on P17 (day 7 [P17-P23] for EPO). At 2 months of age, animals underwent novel object recognition, cylinder rearing, and open field testing to assess recognition memory, sensorimotor function, and anxiety in adulthood.

RESULTS

MSC, MSC/EPO, and EPO3 improved brain volume when administered at 3 or 7 days after middle cerebral artery occlusion. MSC/EPO also enhanced long-term recognition memory with either day 3 or day 7 treatment, but EPO3 had the most long-term benefit, improving recognition memory and exploratory behavior and reducing anxiety.

CONCLUSIONS

These data suggest that single-dose MSC/EPO and multidose systemic EPO improve long-term neurobehavioral outcomes even when administration is delayed, although EPO was the most effective treatment overall. It is possible that EPO represents a final common pathway for improved long-term repair, although the specific mechanisms remain to be determined.

Dysmaturation of Premature Brain: Importance, Cellular Mechanisms, and Potential Interventions

Prematurity, especially preterm birth (less than 32 weeks' gestation), is common and associated with high rates of both survival and neurodevelopmental disability, especially apparent in cognitive spheres. The neuropathological substrate of this disability is now recognized to be related to a variety of dysmaturational disturbances of the brain. These disturbances follow initial brain injury, particularly cerebral white matter injury, and involve many of the extraordinary array of developmental events active in cerebral white and gray matter structures during the premature period. This review delineates these developmental events and the dysmaturational disturbances that occur in premature infants. The cellular mechanisms involved in the genesis of the dysmaturation are emphasized, with particular focus on the preoligodendrocyte. A central role for the diffusely distributed activated microglia and reactive astrocytes in the dysmaturation is now apparent. As these dysmaturational cellular mechanisms appear to occur over a relatively long time window, interventions to prevent or ameliorate the dysmaturation, that is, neurorestorative interventions, seem possible. Such interventions include pharmacologic agents, especially erythropoietin, and particular attention has also been paid to such nutritional factors as quality and source of milk, breastfeeding, polyunsaturated fatty acids, iron, and zinc. Recent studies also suggest a potent role for interventions directed at various experiential factors in the neonatal period and infancy, i.e., provision of optimal auditory and visual exposures, minimization of pain and stress, and a variety of other means of environmental behavioral enrichment, in enhancing brain development.

Concise Review: Stem Cell Therapy for Stroke Patients: Are We There Yet?

Four decades of preclinical research demonstrating survival, functional integration, and behavioral effects of transplanted stem cells in experimental stroke models have provided ample scientific basis for initiating limited clinical trials of stem cell therapy in stroke patients. Although safety of the grafted cells has been overwhelmingly documented, efficacy has not been forthcoming. Two recently concluded stroke clinical trials on mesenchymal stem cells (MSCs) highlight the importance of strict adherence to the basic science findings of optimal transplant regimen of cell dose, timing, and route of delivery in enhancing the functional outcomes of cell therapy. Echoing the Stem Cell Therapeutics as an Emerging Paradigm for Stroke and Stroke Treatment Academic Industry Roundtable call for an NIH‐guided collaborative consortium of multiple laboratories in testing the safety and efficacy of stem cells and their derivatives, not just as stand‐alone but preferably in combination with approved thrombolytic or thrombectomy, may further increase the likelihood of successful fruition of translating stem cell therapy for stroke clinical application. The laboratory and clinical experience with MSC therapy for stroke may guide the future translational research on stem cell‐based regenerative medicine in neurological disorders. stem cells translational medicine2019;8:983&988

Perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke is a relatively common and serious neurologic disorder that can affect the fetus, the preterm, and the term-born infant. It carries significant long-term disabilities. Herein we describe the current understanding of its etiology, pathophysiology and classification, different presentations, and optimal early management. We discuss the role of different brain imaging modalities in defining the extent of lesions and the impact this has on the prediction of outcomes. In recent years there has been progress in treatments, making early diagnosis and the understanding of likely morbidities imperative. An overview is given of the range of possible outcomes and optimal approaches to follow-up and support for the child and their family in the light of present knowledge.

Intra-arterial transplantation of human bone marrow mesenchymal stem cells (hBMMSCs) improves behavioral deficits and alters gene expression in rodent stroke model

Stroke is a multi-factorial polygenic disease and is a major cause of death and adult disability. Administration of bone marrow stem cells protects ischemic rat brain by facilitating recovery of neurological functions. But the molecular mechanism of stem cells action and their effect on gene expression is not well explored. In this study, we have transplanted 1 × 10⁶ human bone marrow mesenchymal stem cells (hBMMSCs) in middle cerebral artery occluded (MCAo) adult male Wistar rats through intracarotid artery route at 24 h after surgery. Motor behavioral tests (rotarod and open field) were performed to assess the changes in motor functions at day 0 and day1, 4, 8 and 14. The expression of studied genes at mRNA and protein level was quantified by using Q-PCR and western blotting, respectively. Further, we have assessed the methylation pattern of promoter of these genes by using methylation-specific PCR. Data were analyzed statistically and correlated. A significant improvement in behavioral deficits was observed in stem cells treated group after 14th day post stroke. Significantly (p < 0.05) increased mRNA and protein levels of brain derived neurotrophic factor and ANP genes in hBMMSCs treated group along with decrease in methylation level at their promoter was observed. On the other hand, significantly decreased mRNA and protein level of TSP1 and WNK1 in hBMMSCs treated group was observed. In conclusion, hBMMSCs administration significantly improves the behavioral deficits by improving motor and locomotor coordination. The promoter of TSP1 and WNK1 genes was found to be hyper-methylated in hBMMSCs group resulting in their decreased expression while the promoter of ANP and brain derived neurotrophic factor was found to be hypo-methylated. This study might shed a light on how hBMMSCs affect the gene expression by modulating methylation status.

Stem Cell Recipes of Bone Marrow and Fish: Just What the Stroke Doctors Ordered

Stem cell therapy for stroke has advanced from the laboratory to the clinic, but remains as an experimental treatment. Two lines of transplant regimens have emerged, namely the "early bird" peripheral injections in subacute stroke patients and the "late night" direct intracerebral treatments in chronic stroke patients. Autologous bone marrow-derived stem cells, which only required minimal manipulations during graft cell preparation, gained fast-track entry into the clinic, while gene modified stem cells necessitated overcoming more stringent regulatory criteria before they were approved for clinical use. Safety of the stem cell therapy can be declared from these clinical trials, but efficacy warrants further investigations. Here, we offer insights into the translation of cell therapy from the laboratory to the clinic, in the hopes that highlighting the lessons we learned from this experience will guide the optimization of functional outcomes of future clinical trials of stem cell therapy for stroke.

Application of mesenchymal stem cells in paediatrics

Mesenchymal stem cells (MSC) were described by Friedenstein in the 1970s as being a group of bone marrow non-hematopoietic cells that are the source of fibroblasts. Since then, knowledge about the therapeutic potential of MSCs has significantly increased. MSCs are currently used for the treatment of many diseases, both in adults and children. MSCs are used successfully in the case of autoimmune diseases, including rheumatic diseases, diabetes mellitus type 1, gastroenterological and neurological diseases. Moreover, treatment of such organ disorders as damage or hypoxia through application of MSC therapy has shown to be satisfactory. In addition, there are some types of congenital disorders, including osteogenesis imperfecta and Spinal Muscular Atrophy, that may be treated with cellular therapy. Most studies showed no other adverse effects than fever. Our study is an analysis that particularly focuses on the registered trials and results of MSCs application to under 18 patients with acute, chronic, recurrent, resistance and corticosteroids types of Graft-versus-Host Disease (GvHD). Stem cells currently play an important role in the treatment of many diseases. Long-term studies conducted on animals have shown that cell therapy is both effective and safe. The number of indications for use of these cells in the course of treatment of people is constantly increasing. The results of subsequent studies provide important data justifying the application of MSCs in the course of treatment of many diseases whose treatment is ineffective when utilizing other approaches.

Recent Advances in Stem Cell-Based Therapeutics for Stroke

Regenerative medicine for central nervous system disorders, including stroke, has challenged the non-regenerative capacity of the brain. Among the many treatment strategies tailored towards repairing the injured brain, stem cell-based therapeutics have been demonstrated as safe and effective in animal models of stroke, and are being tested in limited clinical trials. We address here key lab-to-clinic translational research that relate to efficacy, safety, and mechanism of action underlying stem cell therapy. Recognizing the multi-pronged cell death processes associated with stroke that will likely require combination therapies, we next discuss potent drugs and novel technologies directed at improving the functional outcomes of stem cell-based therapeutics. We also examine discrepant transplant regimens between preclinical studies and clinical trials, as well as missing appropriate control arm (i.e., stroke subjects undergoing rehabilitation) on which to directly compare the therapeutic benefits of cell therapy. Finally, the bioethics of cell therapy is presented in order to assess its prevailing social status. With preliminary results now being reported from on-going clinical trials of stem cell therapy for stroke, a careful assessment of the true functional benefits of this novel treatment will further direct the future of regenerative medicine for neurological disorders.

Amnion-derived stem cell transplantation: A novel treatment for neurological disorders

In this review, we evaluated the literature reporting the use of amniotic stem cells (ASCs) in regenerative medicine for the treatment of neurological disorders. There is an increasing amount of evidence that indicates the exacerbation of the primary injury by inflammation in neurological disorders characterized by rampant inflammation, thereby increasing damage to the central nervous system (CNS). To address this, we focus on the amnion cells' anti-inflammatory properties, which make their transplantation a promising treatment for these disorders. In addition, we offered insights into new applications of the ASC in the fields of regenerative medicine and tissue engineering.

What can you do to protect the newborn brain?

PURPOSE OF REVIEW

Hypoxic-ischemic brain injury is a leading cause of mortality and morbidity in neonates. Treating such injury by interrupting the excitotoxic-oxidative cascade is of immense importance. This review will focus on novel techniques of neuroprotection and describe the latest advances in established therapeutic methods.

KEY FINDINGS

Although the primacy of therapeutic hypothermia in treating hypoxic-ischemic encephalopathy is well established, recent research establishes that the arbitrarily chosen regimen of cooling to 33°C for 72 h may indeed be the most appropriate method. The optimal duration of antenatal magnesium therapy for neuroprotection remains unsettled, though it is reassuring that even 12 h or less of magnesium therapy results in comparable neurological outcomes. Combining adjuvant therapies such as melatonin or erythropoietin with therapeutic hypothermia results in favorable neurological outcomes compared with hypothermia alone. Finally, stem cell-based therapies show considerable potential in preclinical studies.

SUMMARY

Significant advances have occurred in the management of neonatal brain injury. With establishment of the optimal temperature and duration of hypothermia, combinatory therapies using adjuncts hold the greatest promise. Promising preclinical approaches such as stem cell-based therapy and use of noble gases need to be confirmed with clinical trials.