The neurorestorative effect of human amniotic fluid stem cells on the chronic phase of neonatal hypoxic-ischemic encephalopathy in mice.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) remains a major cause of cerebral palsy. Increasing evidence has suggested that mesenchymal stem cells have a favorable effect on HIE. However, the efficacy of human amniotic fluid stem cells (hAFS) for HIE, especially in the chronic phase, remains unclear. The aim of this study was to determine the neurorestorative effect of hAFS on the chronic phase of HIE. METHODS: hAFS were isolated from AF cells as CD117-positive cells. HI was induced in 9-day-old mice. Animals intranasally received hAFS or phosphate-buffered saline at 10 days post HI and were harvested for histological analysis after functional tests at 21 days post HI. We also implanted PKH26-positive hAFS to assess their migration to the brain. Finally, we determined gene expressions of trophic factors in hAFS co-cultured with HI brain extract. RESULTS: hAFS improved sensorimotor deficits in HIE by gray and white matter restoration and neuroinflammation reduction followed by migration to the lesion. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal cell-derived factor-1 (SDF-1) gene expressions in hAFS were elevated when exposed to HI-induced brain extract. CONCLUSION: hAFS induced functional recovery by exerting neurorestorative effects in HIE mice, suggesting that intranasal administration of hAFS could be a novel treatment for HIE, especially in the chronic phase.

The maximum value of bispectral index predicts outcome in hypoxic-ischemic encephalopathy after resuscitation, better than minimum or mean value.

OBJECTIVE: Although bispectral index (BIS) has been widely used for predicting neurological outcomes in clinical practice, its optimal value concerning maximum (BISmax), minimum (BISmin) and mean (BISmean) on accurately predicting the prognosis of patients with hypoxic-ischemic encephalopathy (HIE) after resuscitation has not been clearly determined. METHODS: For a total number of 45 cases, the duration of each BIS measurement was 12 h, with the data collected at a 30 min interval. Outcome was recorded as survival and non-survival count 60 days after the resuscitation. Receiver operator characteristic curve was used to assess the BISmax, BISmin and BISmean for predicting clinical outcome. RESULTS: By the end of observation, 20 cases (44.4%) survived with a significantly higher BISmax. The area under the curve for BISmax of predicting survival was the highest compared to BISmin and BISmean. The optimal cut-off value of BISmax was 71.5 with 100% sensitivity and 60% specificity. Ten patients presented BIS value down to zero at any time point did not survive the observation. CONCLUSION: The BISmax is a better outcome predictor than BISmin or BISmean for patients with HIE after resuscitation. Lower BISmax represents higher risk of mortality. Additionally, BIS value decreases to zero represents a poor outcome.

Assessment of long-term safety and efficacy of intranasal mesenchymal stem cell treatment for neonatal brain injury in the mouse.

BACKGROUND: For clinical translation, we assessed whether intranasal mesenchymal stem cell (MSC) treatment after hypoxia-ischemia (HI) induces neoplasia in the brain or periphery at 14 mo. Furthermore, the long-term effects of MSCs on behavior and lesion size were determined. METHOD: HI was induced in 9-d-old mice. Pups received an intranasal administration of 0.5 × 10(6) MSCs or vehicle at 10 d post-HI. Full macroscopical and microscopical pathological analysis of 39 organs per mouse was performed. Sensorimotor behavior was assessed in the cylinder-rearing test at 10 d, 28 d, 6 mo, and 9 mo. Cognition was measured with the novel object recognition test at 3 and 14 mo post-HI. Lesion size was determined by analyzing mouse-anti-microtubule-associated protein 2 (MAP2) and mouse-anti-myelin basic protein (MBP) staining at 5 wk and 14 mo. RESULTS: At 14 mo post-HI, we did not observe any neoplasia in the nasal turbinates, brain, or other organs of HI mice treated with MSCs. Furthermore, our results show that MSC-induced improvement of sensorimotor and cognitive function is long lasting. In contrast, HI-vehicle mice showed severe behavioral impairment. Recovery of MAP2- and MBP-positive area lasted up to 14 mo following MSC treatment. CONCLUSION: Our results provide strong evidence of the long-term safety and positive effects of MSC treatment following neonatal HI in mice.

Feasibility of autologous cord blood cells for infants with hypoxic-ischemic encephalopathy.

OBJECTIVE: To assess feasibility and safety of providing autologous umbilical cord blood (UCB) cells to neonates with hypoxic-ischemic encephalopathy (HIE). STUDY DESIGN: We enrolled infants in the intensive care nursery who were cooled for HIE and had available UCB in an open-label study of non-cyropreserved autologous volume- and red blood cell-reduced UCB cells (up to 4 doses adjusted for volume and red blood cell content, 1-5 × 10(7) cells/dose). We recorded UCB collection and cell infusion characteristics, and pre- and post-infusion vital signs. As exploratory analyses, we compared cell recipients' hospital outcomes (mortality, oral feeds at discharge) and 1-year survival with Bayley Scales of Infant and Toddler Development, 3rd edition scores ≥85 in 3 domains (cognitive, language, and motor development) with cooled infants who did not have available cells. RESULTS: Twenty-three infants were cooled and received cells. Median collection and infusion volumes were 36 and 4.3 mL. Vital signs including oxygen saturation were similar before and after infusions in the first 48 postnatal hours. Cell recipients and concurrent cooled infants had similar hospital outcomes. Thirteen of 18 (74%) cell recipients and 19 of 46 (41%) concurrent cooled infants with known 1-year outcomes survived with scores >85. CONCLUSIONS: Collection, preparation, and infusion of fresh autologous UCB cells for use in infants with HIE is feasible. A randomized double-blind study is needed.

Stem cells for brain repair in neonatal hypoxia-ischemia.

Neonatal hypoxic-ischemic insults are a significant cause of pediatric encephalopathy, developmental delays, and spastic cerebral palsy. Although the developing brain's plasticity allows for remarkable self-repair, severe disruption of normal myelination and cortical development upon neonatal brain injury are likely to generate life-persisting sensory-motor and cognitive deficits in the growing child. Currently, no treatments are available that can address the long-term consequences. Thus, regenerative medicine appears as a promising avenue to help restore normal developmental processes in affected infants. Stem cell therapy has proven effective in promoting functional recovery in animal models of neonatal hypoxic-ischemic injury and therefore represents a hopeful therapy for this unmet medical condition. Neural stem cells derived from pluripotent stem cells or fetal tissues as well as umbilical cord blood and mesenchymal stem cells have all shown initial success in improving functional outcomes. However, much still remains to be understood about how those stem cells can safely be administered to infants and what their repair mechanisms in the brain are. In this review, we discuss updated research into pathophysiological mechanisms of neonatal brain injury, the types of stem cell therapies currently being tested in this context, and the potential mechanisms through which exogenous stem cells might interact with and influence the developing brain.

Human dental pulp-derived stem cells protect against hypoxic-ischemic brain injury in neonatal mice.

BACKGROUND AND PURPOSE: Perinatal hypoxia-ischemia (HI) has high rates of neurological deficits and mortality. So far, no effective treatment for HI brain injury has been developed. In this study, we investigated the therapeutic effects of stem cells from human exfoliated deciduous teeth (SHED) for the treatment of neonatal HI brain injury. METHODS: Unilateral HI was induced in postnatal day 5 (P5) mice. Twenty-four hours later, SHED, human skin fibroblasts, or serum-free conditioned medium derived from these cells was injected into the injured brain. The effects of cell transplantation or conditioned medium injection on the animals' neurological and pathophysiological recovery were evaluated. RESULTS: Transplanted SHED, but not fibroblasts, significantly reduced the HI-induced brain-tissue loss and improved neurological function. SHED also improved the survival of the HI mice. The engrafted SHED rarely differentiated into neural lineages; however, their transplantation inhibited the expression of proinflammatory cytokines, increased the expression of anti-inflammatory ones, and significantly reduced apoptosis. Notably, the intracerebral administration of SHED-conditioned medium also significantly improved the neurological outcome, inhibited apoptosis, and reduced tissue loss. CONCLUSIONS: SHED transplantation into the HI-injured brain resulted in remarkable neurological and pathophysiological recovery. Our findings indicate that paracrine factors derived from SHED support a neuroprotective microenvironment in the HI brain. SHED graft and SHED-conditioned medium may provide a novel neuroprotective therapy for HI.

The therapeutic potential of human umbilical cord blood transplantation for neonatal hypoxic-ischemic brain injury and ischemic stroke.

Human umbilical cord blood (HUCB) cells are rich source of immature stem cells, which have the potential to repair lost tissue. Intractable central nervous system (CNS) disorders are important targets for regenerative medicine, and the application of HUCB cells is being investigated in animal models of CNS disorders. Transplantation of HUCB has induced functional improvements in these animal models due to multiple therapeutic effects including neuroprotection, anti-inflammation, angiogenesis, and neurogenesis. HUCB cells are easily available and safer than other stem cells used in transplantation therapy. In this review, we focus on HUCB transplantation as an encouraging therapeutic approach for animal models of neonatal hypoxic-ischemic brain injury and ischemic stroke.

[The role of phototherapy in the rehabilitation of newborn babies and infants].

This review is devoted to the problems pertaining to the rational application of phototherapy in the rehabilitation of newborn babies and infants. The analysis of the classical and present-day literature sources provided materials for the development of the rationale for the use of colour-puncture therapy. The data included in this review indicate that phototherapy has positive effect on the immune and rehabilitative processes in the newborns following surgical interventions and in the breast-fed infants suffering hypoxic ischemic encephalopathy. Phototherapy is equally beneficial when the newborn babies need to be treated for cutaneous and nervous disorders or undergo a surgical operation. Moreover, it can be applied to manage endocrine disorders and diseases of the vegetative nervous system. The photo-induced changes in the skin influence the concentration of biologically active compounds in the systemic circulation. It is believed that colour-puncture therapy makes it possible to selectively affect biologically active points in the channel-meridian system of the newborn babies and infants.

Baby STEPS: a giant leap for cell therapy in neonatal brain injury.

We advance Baby STEPS or Stem cell Therapeutics as an Emerging Paradigm in Stroke as a guide in facilitating the critical evaluation in the laboratory of the safety and efficacy of cell therapy for neonatal encephalopathy. The need to carefully consider the clinical relevance of the animal models in mimicking human neonatal brain injury, selection of the optimal stem cell donor, and the application of functional outcome assays in small and large animal models serve as the foundation for preclinical work and beginning to understand the mechanism of this cellular therapy. The preclinical studies will aid our formulation of a rigorous human clinical trial that encompasses not only efficacy testing but also monitoring of safety indices and demonstration of mechanisms of action. This schema forms the basis of Baby STEPS. Our goal is to resonate the urgent call to enhance the successful translation of cell therapy from the laboratory to the clinic.

[Does decompressive craniectomy improve other parameters besides ICP? Effects of the decompressive craniectomy on tissular pressure?]. / ¿Mejora la craniectomía descompresiva otros parámetros además de la PIC? Efectos de la craniectomía descompresiva en la presión tisular.

Second level therapeutic maneuvres for controlling intracranial hypertension (ICH) proposed by the European Brain Injury Consortium and the American Association of Neurological Surgeons include barbiturates, moderate hypothermia and more recently the decompressive craniectomy (DC).In most patients, ICP can be maintained below 25 mmHg after a DC. However, the exact effect of DC on brain oxygenation (PtiO2) still unclear. From our point of view the ptIo2 monitoring with the probe located in the healthy area of the most severely damaged cerebral hemisphere is not only a important tool for timing craniectomy in the future but also for evaluating the therapeutic effectivity of DC.

Human neural stem cell grafts modify microglial response and enhance axonal sprouting in neonatal hypoxic-ischemic brain injury.

BACKGROUND AND PURPOSE: Hypoxic-ischemic (HI) brain injury in newborn infants represents a major cause of cerebral palsy, development delay, and epilepsy. Stem cell-based therapy has the potential to rescue and replace the ischemic tissue caused by HI and to restore function. However, the mechanisms by which stem cell transplants induce functional recovery are yet to be elucidated. In the present study, we sought to investigate the efficacy of human neural stem cells derived from human embryonic stem cells in a rat model of neonatal HI and the mechanisms enhancing brain repair. METHODS: The human neural stem cells were genetically engineered for in vivo molecular imaging and for postmortem histological tracking. Twenty-four hours after the induction of HI, animals were grafted with human neural stem cells into the forebrain. Motor behavioral tests were performed the fourth week after transplantation. We used immunocytochemistry and neuroanatomical tracing to analyze neural differentiation, axonal sprouting, and microglia response. Treatment-induced changes in gene expression were investigated by microarray and quantitative polymerase chain reaction. RESULTS: Bioluminescence imaging permitted real time longitudinal tracking of grafted human neural stem cells. HI transplanted animals significantly improved in their use of the contralateral impeded forelimb and in the Rotorod test. The grafts showed good survival, dispersion, and differentiation. We observed an increase of uniformly distributed microglia cells in the grafted side. Anterograde neuroanatomical tracing demonstrated significant contralesional sprouting. Microarray analysis revealed upregulation of genes involved in neurogenesis, gliogenesis, and neurotrophic support. CONCLUSIONS: These results suggest that human neural stem cell transplants enhance endogenous brain repair through multiple modalities in response to HI.

Fibroblast growth factor-2 overexpression in transplanted neural progenitors promotes perivascular cluster formation with a neurogenic potential.

Stem/progenitor cell-based therapies hold promises for repairing the damaged nervous system. However, the efficiency of these approaches for neuronal replacement remains very limited. A major challenge is to develop pretransplant cell manipulations that may promote the survival, engraftment, and differentiation of transplanted cells. Here, we investigated whether overexpression of fibroblast growth factor-2 (FGF-2) in grafted neural progenitors could improve their integration in the host tissue. We show that FGF-2-transduced progenitors grafted in the early postnatal rat cortex have the distinct tendency to associate with the vasculature and establish multiple proliferative clusters in the perivascular environment. The contact with vessels appears to be critical for maintaining progenitor cells in an undifferentiated and proliferative phenotype in the intact cortex. Strikingly, perivascular clusters of FGF-2 expressing cells seem to supply immature neurons in an ischemic environment. Our data provide evidence that engineering neural progenitors to overexpress FGF-2 may be a suitable strategy to improve the integration of grafted neural progenitor cells with the host vasculature thereby generating neurovascular clusters with a neurogenic potential for brain repair.

Neural stem cells: properties and therapeutic potentials for hypoxic-ischemic brain injury in newborn infants.

Neural stem cells (NSCs) are defined by their ability to self-renew, to differentiate into cells of all glial and neuronal lineages throughout the neuraxis, and to populate developing or degenerating central nervous system (CNS) regions. The recognition that NSCs propagated in culture could be reimplanted into the mammalian brain, where they might integrate appropriately throughout the mammalian CNS and stably express foreign genes, has unveiled a new role for neural transplantation and gene therapy and a possible strategy for addressing the CNS manifestations of diseases that hitherto had been refractory to intervention. An intriguing phenomenon with possible therapeutic potentials has begun to emerge from our observations of the behavior of NSCs in animal models of neonatal hypoxic-ischemic (HI) brain injury. During phases of active neurodegeneration, factors seem to be transiently elaborated to which NSCs may respond by migrating to degenerating regions and differentiating specifically towards replacement of dying neural cells. NSCs may attempt to repopulate and reconstitute ablated regions. These 'repair mechanisms' may actually reflect the reexpression of basic developmental principles that may be harnessed for therapeutic ends. In addition, NSCs may serve as vehicles for gene delivery and appear capable of simultaneous neural cell replacement and gene therapy (e.g. with factors that might enhance neuronal differentiation, neurites outgrowth, proper connectivity, and/or neuroprotection). When combined with certain synthetic biomaterials, NSCs may be even more effective in 'engineering' the damaged CNS towards reconstitution. We have also cultured human NSCs or progenitors as neurospheres which were derived from fetal cadavers at 13 weeks of gestation, and transplanted them into HI-injured immature brains to investigate their therapeutic potentials in this type of model.

The clinical utility of the Kopitnik arteriovenous malformation microclip during STA-MCA bypass surgery.

PURPOSE: Yasagil temporary clips have been widely used in extracranial-intracranial (EC-IC) arterial bypass surgery. However, the extremely delicate vessels involved often require the application of finer clips. We report on the use of the Kopitnik arteriovenous malformation (AVM) microclip system for superficial temporal artery-middle cerebral artery (STA-MCA) bypass. METHODS: Kopitnik AVM microclips are new mechanical devices that are used during AVM surgery. They exert a pre-defined closing force of 50-70 g, and also feature a special, pyramid-shaped structure stamped on inner surfaces of the blades. These characteristics avoid vascular intimal injury and provide a secure grip. We prospectively studied their use in 15 patients requiring STA-MCA anastomosis. RESULTS: Clinical results were excellent and there were no new ischemic events during 6-months' follow-up. CONCLUSIONS: Kopitnik AVM microclips have several advantages; they have small and variously sized clip blades (2, 3, 4 and 5 mm), and the small clip head allows the operator an excellent view of the pathology and clip status. The Kopitnik AVM microclip appears to be clinically effective and safe for EC-IC bypass surgery, especially when smaller vessels are involved.

Prediction of neurological outcome using bispectral index monitoring in patients with severe ischemic-hypoxic brain injury undergoing emergency surgery.

BACKGROUND: Predicting outcome from ischemic-hypoxic brain injury can be difficult in patients rushed to the operating room for time-critical emergency surgery. The authors chose to evaluate the prognostic ability of bispectral index (BIS) in this setting. METHODS: Twenty-five critically ill, unconscious patients with ischemic-hypoxic brain injury undergoing emergency surgery were prospectively studied. Clinical evaluation, laboratory investigations, BIS, and burst suppression ratio were recorded before and during surgery. Neurologic outcome of the patients was measured according to the Glasgow outcome scale at 30 days after injury, with poor neurologic outcome defined as severe disability or death. RESULTS: The incidence of poor neurologic outcome was 68%. Neither clinical judgment (P = 0.40) nor pupillary responses (P = 0.21) were predictive of neurologic outcome after surgery. An abnormal BIS trace was strongly associated with poor neurologic outcome, positive likelihood ratio 6.6 (95% CI 1.7-36.4; exact test P = 0.002). Some BIS values were significantly different when comparing patients with and without poor outcome: c-statistics for the average BIS and maximal electroencephalographic burst-suppression were 0.80 (95% CI 0.62-0.98; P = 0.017) and 0.84 (95% CI 0.68-0.99; P = 0.007), respectively. A normal BIS (P < 0.0005) but not clinical judgment (P = 0.16) could identify a group of patients more likely to survive with a good neurologic outcome. CONCLUSIONS: BIS, when compared with clinical judgment and routine laboratory tests, provides useful information that may identify patients with a good chance of recovery after ischemic-hypoxic brain injury requiring emergency surgery.

Lies, damned lies, and statistics: a neurosurgical perspective on the international randomized trial of extracranial to intracranial arterial bypass surgery.

The abrupt occurrence of a devastating stroke has been referred to as "super death." It has long been realized that ischemic cerebral vascular disease may become symptomatic with a wide variety of clinical patterns. A robust circle of Willis has been recognized for its major protective function in many cases. When it became possible to actually create new collateral circulation to the brain by microsurgical techniques, significant enthusiasm arose. This enthusiasm was interrupted by the negative results of the international randomized trial. Further analysis of the trial raised serious questions regarding incomplete randomization by contributors to the study, and there remains uncertainty about important potential benefits for some individuals. Long-term follow-up of 3 patients having different and complex circumstances is described to emphasize this concern. After the creation of reliable collateral circulation to the brain, none has experienced new ischemic deficit during the subsequent follow-up of 27, 25, and 12 years, respectively.

Expression of FGF-2 in neural progenitor cells enhances their potential for cellular brain repair in the rodent cortex.

Strategies to enhance the capacity of grafted stem/progenitors cells to generate multipotential, proliferative and migrating pools of cells in the postnatal brain could be crucial for structural repair after brain damage. We investigated whether the over-expression of basic fibroblast growth factor 2 (FGF-2) in neural progenitor cells (NPCs) could provide a robust source of migrating NPCs for tissue repair in the rat cerebral cortex. Using live imaging we provide direct evidence that FGF-2 over-expression significantly enhances the migratory capacity of grafted NPCs in complex 3D structures, such as cortical slices. Furthermore, we show that the migratory as well as proliferative properties of FGF-2 over-expressing NPCs are maintained after in vivo transplantation. Importantly, after transplantation into a neonatal ischaemic cortex, FGF-2 over-expressing NPCs efficiently invade the injured cortex and generate an increased pool of immature neurons available for brain repair. Differentiation of progenitor cells into immature neurons was correlated with a gradual down-regulation of the FGF-2 transgene. These results reveal an important role for FGF-2 in regulating NPCs functions when interacting with the host tissue and offer a potential strategy to generate a robust source of migrating and immature progenitors for repairing a neonatal ischaemic cortex.

[Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery]. / Detección de episodios de hipoxia tisular isquémica mediante la monitorizaciónneurofisiológica intraoperatoria combinada con la monitorización de la oxigenacióntisular en la cirugía aneurismática.

INTRODUCTION: Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia. We show the utility of the intraoperative monitoring of the oxygen tissue pressure (PtiO2) and the somatosensorial evoked potential (SSEP) for the detection of these situations with the example of a clinical case. CLINICAL CASE: We present the case of a 62 year-old woman, that presented with subarachnoid hemorrhage of aneurysmal origin. The cerebral arteriography demonstrated the existence of an aneurysm of the posterior communicating artery that was treated initially by endovascular procedure with partial exclusion of the aneurysm. For this reason it was decided to complete the treatment with a programmed surgery. The patient was put on an intraoperative monitoring system with a PtiO2 sensor located in the risk area and with SSEP. After positioning the surgical clip the partial oxygen pressure decreased rapidly, as well as the amplitude of the cortical potential of the left posterior tibial nerve. The knowledge of this situation allowed the detection of a trapped posterior communicating artery. After correcting this situation by replacing the surgical clip, both variables recovered to their basal values. CONCLUSIONS: The intraoperative PtiO2 monitoring, combined with neurophysiologic monitoring during aneurysm surgery offers a fast and trustworthy form of early detection of ischemic phenomena caused by bad positioning of the surgical clip.

[The best site of transplantation of neural stem cells into brain in treatment of hypoxic-ischemic damage: experiment with newborn rats].

OBJECTIVE: To investigate the best site of transplantation of neural stem cells (NSCs) into the brain to treat hypoxic-ischemic damage (HIBD). METHODS: Forty-eight 7-day-old Spraque-Dawley rats underwent ligation of the left common carotid artery and exposure to 8% oxygen at 37 degrees C for 2 hours to establish HIBD models and then were randomly divided into 4 equal groups 3 days later: HIBD control group, HIBD + cortex transplantation group (CT group) undergoing NSC transplantation into the sensorimotor cortex, HIBD + hippocampus transplantation group (HT group) undergoing NSC transplantation into the hippocampus, and HIBD + ventricle transplantation group (VT group), undergoing NSC transplantation into the lateral ventricle. Since the rats were 40-day-old, they underwent radial maze water-seeking test and 4 sensorimotor tests. Then the brains of the rats were taken out to undergo histological examination by Nissl staining and immunohistochemistry to observer the 5-bromodeoxyuridine (BrdU) expression. RESULTS: The times the rats took to find the water in all 3 arms of the maze were arranged form short to long in the order HT group < VT group < CT group < HIBD group with significant differences between the HT, VT, and CT groups and HIBD group (All P < 0.05) and between the groups HT and VT and the group CT (both P < 0.05). The results of the 4 sensorimotor tests were arranged from the best to the worst in the order CT group > VT group > HT group > HIBD group with significant differences between the groups CT and VT and the group HIBD (both P < 0.05). Nissl staining showed that the number of normal neurons in the cortex area from more to less were arranged in the order CT group > VT group > HT group > HIBD group; and the number of normal neurons in the CAI area from more to less were arranged in the order HT group > VT group > CT group > HIBD group. CONCLUSION: Transplantation of NSC attenuates the brain damage and the cognitive and sensorimotor dysfunction after HIBD. Transplantation into the lateral ventricle is the most effective.