A comparison of behavioural and histological outcomes of periventricular injection of ibotenic acid in neonatal rats at postnatal days 5 and 7

Recent Investigations on Neurotransmitters' Role in Acute White Matter Injury of Perinatal Glia and Pharmacotherapies-Glia Dynamics in Stem Cell Therapy

Periventricular leukomalacia (PVL) and cerebral palsy are two neurological disease conditions developed from the premyelinated white matter ischemic injury (WMI). The significant pathophysiology of these diseases is accompanied by the cognitive deficits due to the loss of function of glial cells and axons. White matter makes up 50% of the brain volume consisting of myelinated and non-myelinated axons, glia, blood vessels, optic nerves, and corpus callosum. Studies over the years have delineated the susceptibility of white matter towards ischemic injury especially during pregnancy (prenatal, perinatal) or immediately after child birth (postnatal). Impairment in membrane depolarization of neurons and glial cells by ischemia-invoked excitotoxicity is mediated through the overactivation of NMDA receptors or non-NMDA receptors by excessive glutamate influx, calcium, or ROS overload and has been some of the well-studied molecular mechanisms conducive to the injury of white matter. Expression of glutamate receptors (GluR) and transporters (GLT1, EACC1, and GST) has significant influence in glial and axonal-mediated injury of premyelinated white matter during PVL and cerebral palsy. Predominantly, the central premyelinated axons express extensive levels of functional NMDA GluR receptors to confer ischemic injury to premyelinated white matter which in turn invoke defects in neural plasticity. Several underlying molecular mechanisms are yet to be unraveled to delineate the complete pathophysiology of these prenatal neurological diseases for developing the novel therapeutic modalities to mitigate pathophysiology and premature mortality of newborn babies. In this review, we have substantially discussed the above multiple pathophysiological aspects of white matter injury along with glial dynamics, and the pharmacotherapies including recent insights into the application of MSCs as therapeutic modality in treating white matter injury.

Adipose-Derived Stem Cells Reduce Lipopolysaccharide-Induced Myelin Degradation and Neuroinflammatory Responses of Glial Cells in Mice

Brain inflammation is a key event triggering the pathological process associated with many neurodegenerative diseases. Current personalized medicine and translational research in neurodegenerative diseases focus on adipose-derived stem cells (ASCs), because they are patient-specific, thereby reducing the risk of immune rejection. ASCs have been shown to exert a therapeutic effect following transplantation in animal models of neuroinflammation. However, the mechanisms by which transplanted ASCs promote cell survival and/or functional recovery are not fully understood. We investigated the effects of ASCs in in vivo and in vitro lipopolysaccharide (LPS)-induced neuroinflammatory models. Brain damage was evaluated immunohistochemically using specific antibody markers of microglia, astroglia and oligodendrocytes. ASCs were used for intracerebral transplantation, as well as for non-contact co-culture with brain slices. In both in vivo and in vitro models, we found that LPS caused micro- and astroglial activation and oligodendrocyte degradation, whereas the presence of ASCs significantly reduced the damaging effects. It should be noted that the observed ASCs protection in a non-contact co-culture suggested that this effect was due to humoral factors via ASC-released biomodulatory molecules. However, further clinical studies are required to establish the therapeutic mechanisms of ASCs, and optimize their use as a part of a personalized medicine strategy.

The Potential of Stem Cell Therapy to Repair White Matter Injury in Preterm Infants: Lessons Learned From Experimental Models

Diffuse white matter injury (dWMI) is a major cause of morbidity in the extremely preterm born infant leading to life-long neurological impairments, including deficits in cognitive, motor, sensory, psychological, and behavioral functioning. At present, no treatment options are clinically available to combat dWMI and therefore exploration of novel strategies is urgently needed. In recent years, the pathophysiology underlying dWMI has slowly started to be unraveled, pointing towards the disturbed maturation of oligodendrocytes (OLs) as a key mechanism. Immature OL precursor cells in the developing brain are believed to be highly sensitive to perinatal inflammation and cerebral oxygen fluctuations, leading to impaired OL differentiation and eventually myelination failure. OL lineage development under normal and pathological circumstances and the process of (re)myelination have been studied extensively over the years, often in the context of other adult and pediatric white matter pathologies such as stroke and multiple sclerosis (MS). Various studies have proposed stem cell-based therapeutic strategies to boost white matter regeneration as a potential strategy against a wide range of neurological diseases. In this review we will discuss experimental studies focusing on mesenchymal stem cell (MSC) therapy to reduce white matter injury (WMI) in multiple adult and neonatal neurological diseases. What lessons have been learned from these previous studies and how can we translate this knowledge to application of MSCs for the injured white matter in the preterm infant? A perspective on the current state of stem cell therapy will be given and we will discuss different important considerations of MSCs including cellular sources, timing of treatment and administration routes. Furthermore, we reflect on optimization strategies that could potentially reinforce stem cell therapy, including preconditioning and genetic engineering of stem cells or using cell-free stem cell products, to optimize cell-based strategy for vulnerable preterm infants in the near future.

What are the Best Animal Models for Testing Early Intervention in Cerebral Palsy?

Interventions to treat cerebral palsy should be initiated as soon as possible in order to restore the nervous system to the correct developmental trajectory. One drawback to this approach is that interventions have to undergo exceptionally rigorous assessment for both safety and efficacy prior to use in infants. Part of this process should involve research using animals but how good are our animal models? Part of the problem is that cerebral palsy is an umbrella term that covers a number of conditions. There are also many causal pathways to cerebral palsy, such as periventricular white matter injury in premature babies, perinatal infarcts of the middle cerebral artery, or generalized anoxia at the time of birth, indeed multiple causes, including intra-uterine infection or a genetic predisposition to infarction, may need to interact to produce a clinically significant injury. In this review, we consider which animal models best reproduce certain aspects of the condition, and the extent to which the multifactorial nature of cerebral palsy has been modeled. The degree to which the corticospinal system of various animal models human corticospinal system function and development is also explored. Where attempts have already been made to test early intervention in animal models, the outcomes are evaluated in light of the suitability of the model.

Could autologous cord blood stem cell transplantation treat cerebral palsy?

The young human brain is highly plastic and thus early brain lesions can lead to aberrant development of connectivity and mapping of functions. This is why initially in cerebral palsy only subtle changes in spontaneous movements are seen after the time of lesion, followed by a progressive evolution of a movement disorder over many months and years. Thus we propose that interventions to treat cerebral palsy should be initiated as soon as possible in order to restore the nervous system to the correct developmental trajectory. One such treatment might be autologous stem cell transplantation either intracerebrally or intravenously. All babies come with an accessible supply of stem cells, the umbilical cord, which can supply cells that could theoretically replace missing neural cell types, or act indirectly by supplying trophic support or modulating inflammatory responses to hypoxia/ischaemia. However, for such radical treatment to be proposed, it is necessary to be able to detect and accurately predict the outcomes of brain injury from a very early age. This article reviews our current understanding of perinatal injuries that lead to cerebral palsy, how well modern imaging might predict outcomes, what stem cells are yielded from umbilical cord blood and experimental models of brain repair using stem cells.

Transplantation of magnetically labeled mesenchymal stem cells in a model of perinatal brain injury

Periventricular white matter injury (PVWMI) in preterm infants is a leading cause of cerebral palsy. Mesenchymal stem cell (MSC) transplantation in experimental models of adult demyelinating conditions is reported to reduce neurological deficits so we investigated their potential for treating developmental PVWMI. Neonatal rat MSCs, when cultured and labeled in vitro with fluorescent, micrometer-sized paramagnetic iron oxide particles (MPIO), retained their differentiation potential. Rats received bilateral intracerebral injections of ibotenic acid at postnatal day 5 causing PVWMI-like lesions with localized hypomyelination and sensorimotor deficits. MPIO-labeled MSCs were transplanted near the lesion in the right hemisphere 1 day postlesioning. Animals receiving cell transplants showed significantly increased antimyelin immunoreactivity in the corpus callosum, and improved reaching and retrieval skills, compared to animals receiving conditioned medium only. In separate experiments, in vivo MRI demonstrated that MPIO-labeled cells migrated away from the injection site toward lesioned areas in both hemispheres, confirmed by microscopy postmortem, but double-labeling studies found little evidence of differentiation into neural phenotypes. MSC transplantation led to significantly more forebrain cell proliferation, assayed by bromodeoxyuridine incorporation, than in controls. MSC transplants may have been neuroprotective and indirectly contributed to brain repair.

New tools in the treatment of motility disorders in children

Gastrointestinal motility disorders can develop in neurologically impaired children and those with congenital malformations of the gut. It is characterized by moderate to severe abdominal pain, vomiting, and failure to thrive. Antral dysmotility after fundoplication and increased sympathetic over activity are 2 factors associated with this condition that make it difficult to treat. This paper proposes a management strategy using metoclopramide, celiac plexus blockade, and thoracic splanchnectomy. It reviews our experience with 11 patients.