Transplant of GABAergic Precursors Restores Hippocampal Inhibitory Function in a Mouse Model of Seizure Susceptibility

16 páginas, 8 figuras.-- Licencia Creative Commons Reconocimiento-No comercial.Defects in GABAergic function can cause epilepsy. In the last years, cell-based therapies have attempted to correct these defects with disparate success on animal models of epilepsy. Recently, we demonstrated that medial ganglionic eminence (MGE)-derived cells grafted into the neonatal normal brain migrate and differentiate into functional mature GABAergic interneurons. These cells are able to modulate the local level of GABA-mediated synaptic inhibition, which suggests their suitability for cell-based therapies. However, it is unclear whether they can integrate in the host circuitry and rescue the loss of inhibition in pathological conditions. Thus, as proof of principle, we grafted MGE-derived cells into a mouse model of seizure susceptibility caused by specific elimination of GABAergic interneuron subpopulations in the mouse hippocampus after injection of the neurotoxic saporin conjugated to substance P (SSP-Sap). This ablation was associated with significant decrease in inhibitory postsynaptic currents (IPSC) on CA1 pyramidal cells and increased seizure susceptibility induced by pentylenetetrazol (PTZ). Grafting of GFP+ MGE-derived cells in SSP-Sap-treated mice repopulates the hippocampal ablated zone with cells expressing molecular markers of mature interneurons. Interestingly, IPSC kinetics on CA1 pyramidal cells of ablated hippocampus significantly increased after transplantation, reaching levels similar to the normal mice. More importantly, this was associated with reduction in seizure severity and decrease in postseizure mortality induced by PTZ. Our data show that MGE-derived cells fulfill most of the requirements for an appropriate cell-based therapy, and indicate their suitability for neurological conditions where a modulation of synaptic inhibition is needed, such as epilepsy.This work was supported by grants from Spanish Ministry of Science and Innovation (SAF 07/61880 and FIS 07/0079), and the Regenerative Medicine Programme from CIPF. M.E.C. and I.Z. were recipients of Miguel Servet contract from Carlos III Institute (Spanish Ministry of Science and Innovation) and Ph.D. fellowship from Generalitat Valenciana, respectively.Peer reviewe

Effect of neuronal precursor cells derived from medial ganglionic eminence in an acute epileptic seizure model

5 páginas, 1 figura, 1 tabla.-- Special Issue: 10th Workshop on the Neurobiology of Epilepsy (WONOEP): Novel Therapeutic Approaches to Epileptogenesis.-- et al.Most of the γ-aminobutyric acid (GABA)ergic interneurons in the cerebral cortex originate from restricted regions of the ventral telencephalon known as the caudal and medial ganglionic eminence (MGE) and from the preoptic area. It is well established that dysfunction of GABAergic interneurons can lead to epilepsy. During the last decade new approaches to prevent, reduce, or reverse the epileptic condition have been studied, including cell-based therapy from different sources. Recent studies have shown that transplanted neuronal precursor cells derived from MGE have the ability to migrate, differentiate into inhibitory GABAergic interneurons, and integrate into cortical and hippocampal networks, modifying the inhibitory tone in the host brain. Therefore, transplantation of neuronal precursors derived from MGE into the postnatal central nervous system (CNS) could modify the neuronal circuitry in neurologic diseases in which inhibitory synaptic function is altered, such as in epilepsy. Here, we evaluated the seizure susceptibility of mice transplanted with MGE-derived cells in the maximum electroconvulsive shock (MES) model and we review some data from different studies using GABAergic precursor or GABA-releasing cell grafts in animal models of seizure and epilepsy.This work was supported by FAPESP, FAPERJ, and CNPq.Peer reviewe

GABAergic precursors grafts in animal models of epilepsy

Trabajo presentado en II EMBO Workshop on Cortical Interneurons in Health and Disease, celebrado en Costa d’en Blanes, Mallorca (España), del 24 al 27 de junio de 2012Introduction: Refractory epilepsy is present in about 30% of TLE patients, despite carefully optimized drug treatment. These patients have no treatment other than major resective surgery. In the last years, cell-based therapies have emerged as a promising alternative. Recently, we have demonstrated that MGE-derived precursors transplanted into the normal adult and neonatal telencephalon migrate, differentiate and incorporate as fully functional GABAergic interneurons. Moreover, grafting in a mouse model of hyperactivity, generated by partial elimination of GABAergic interneurons, replaced the deficit in interneurons and restored the normal levels of inhibition in the ablated hippocampus. To further analyze the use of these precursors as an antiepileptic therapy for refractory TLE epilepsy, we have performed transplants in the pilocarpine mouse model of epilepsy. Results: Intrahippocampal bilateral transplants of GFP+ cells from the MGE were performed 5 days after pilocarpine induction of status epilepticus. We monitorized the control and transplanted mice daily from 2 weeks to 4 months after the transplant to asses the possible antiepileptic effects. We observed a significant delay in the latency time to develop the spontaneous recurrent seizures (SRS) in the transplanted group. In addition, the percentage of transplanted mice that fully developed the SRS was significantly reduced with respect their controls and this small group suffered the SRS four times less frequently. Immohistochemical analysis reveled that GFP+ cells spread widely through CA and DG areas. They differentiated into normal interneuron subtypes, with mature morphology and expressing specific markers such as parvalbumin, somatostatin, NP-Y, and calretinin. Interestingly, we observed a protective effect on the hippocampal sclerosis, correlated with reduced levels of cell death. Grafted cells did not affect the sprouting of mossy fibers, although we cannot discard a direct interaction with the grafted cells. In fact, patch clamp analysis of sIPSC in the grafted area confirmed a modulation of the inhibitory synaptic function. Conclusion: MGE-derived precursor grafts into the hippocampus protects against the development of TLE and elicit a reduction in hippocampal sclerosis. This cell-based therapy could be extremely beneficial for the treatment of refractory epilepsy.Financial Support: Ministerio de Ciencia y Tecnología (SAF 2009- 07746)Peer Reviewe

Cux1 and Cux2 Regulate Dendritic Branching, Spine Morphology, and Synapses of the Upper Layer Neurons of the Cortex

13 páginas, 8 figuras.-- PMCID: PMC2894581Dendrite branching and spine formation determines the function of morphologically distinct and specialized neuronal subclasses. However, little is known about the programs instructing specific branching patterns in vertebrate neurons and whether such programs influence dendritic spines and synapses. Using knockout and knockdown studies combined with morphological, molecular, and electrophysiological analysis, we show that the homeobox Cux1 and Cux2 are intrinsic and complementary regulators of dendrite branching, spine development, and synapse formation in layer II-III neurons of the cerebral cortex. Cux genes control the number and maturation of dendritic spines partly through direct regulation of the expression of Xlr3b and Xlr4b, chromatin remodeling genes previously implicated in cognitive defects. Accordingly, abnormal dendrites and synapses in Cux2−/− mice correlate with reduced synaptic function and defects in working memory. These demonstrate critical roles of Cux in dendritogenesis and highlight subclass-specific mechanisms of synapse regulation that contribute to the establishment of cognitive circuits.This work was supported by MICINN grants (SAF2005-0094, SAF2008-00211, PIE-200820I166, and BFU2007-61774), a grant from Mutua Madrilen˜ a Automovilı´stica (0328-2005), and a grant from the Spanish Comunidad de Madrid CCG08-CSIC/SAL-3464. B. Cubelos holds a fellowship from the CSIC (JAEDoc2008-020), and A. Sebastian-Serrano, from the MICINN (BES-2006-13901). C.A.W. was supported by 2RO1 NS032457 from the NINDS, and J.M. Redondo, by grant SAF2006-08348. C.A.W. is an Investigator of the Howard Hughes Medical Institute. The Centro Nacional de Investigaciones Cardiovasculares is supported by the MICINN and the Pro-CNIC Foundation.Peer reviewe

Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42·4% vs 44·2%; absolute difference -1·69 [-9·58 to 6·11] p=0·67; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5-8] vs 6 [5-8] cm H2O; p=0·0011). ICU mortality was higher in MICs than in HICs (30·5% vs 19·9%; p=0·0004; adjusted effect 16·41% [95% CI 9·52-23·52]; p<0·0001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0·80 [95% CI 0·75-0·86]; p<0·0001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status