Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model.
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ABSTRACT:
SUBMITTER: Lozovaya N
PROVIDER: S-EPMC4143949 | biostudies-literature | 2014 Aug
REPOSITORIES: biostudies-literature
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Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model.
Lozovaya N N Gataullina S S Tsintsadze T T Tsintsadze V V Pallesi-Pocachard E E Minlebaev M M Goriounova N A NA Buhler E E Watrin F F Shityakov S S Becker A J AJ Bordey A A Milh M M Scavarda D D Bulteau C C Dorfmuller G G Delalande O O Represa A A Cardoso C C Dulac O O Ben-Ari Y Y Burnashev N N
Nature communications 20140801
Tuberous sclerosis complex (TSC), caused by dominant mutations in either TSC1 or TSC2 tumour suppressor genes is characterized by the presence of brain malformations, the cortical tubers that are thought to contribute to the generation of pharmacoresistant epilepsy. Here we report that tuberless heterozygote Tsc1(+/-) mice show functional upregulation of cortical GluN2C-containing N-methyl-D-aspartate receptors (NMDARs) in an mTOR-dependent manner and exhibit recurrent, unprovoked seizures durin ...[more]
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Project description:BackgroundEpilepsy in tuberous sclerosis complex (TSC) typically presents with early onset, multiple seizure types, and intractability. However, variability is observed among individuals. Here, detailed individual data on seizure characteristics collected prospectively during early life were used to define epilepsy profiles in this population.MethodsChildren aged zero to 36 months were followed longitudinally. Caregivers kept daily seizure diaries, including onset and daily counts for each seizure type. Patients with >70% seizure diary completion and >365 diary days were included. Developmental outcomes at 36 months were compared between subgroups.ResultsEpilepsy was seen in 124 of 156 (79%) participants. Seizure onset occurred from zero to 29.5 months; 93% had onset before age 12 months. Focal seizures and epileptic spasms were most common. Number of seizures (for median 897 days) ranged from 1 to 9128. Hierarchical clustering based on six metrics of seizure burden (age of onset, total seizures, ratio of seizure days to nonseizure days, seizures per seizure day, and worst seven- and 30-day stretches) revealed two distinct groups with broadly favorable and unfavorable epilepsy profiles. Subpopulations within each group showed clinically meaningful differences in seizure burden. Groups with higher seizure burden had worse developmental outcomes at 36 months.ConclusionsAlthough epilepsy is highly prevalent in TSC, not all young children with TSC have the same epilepsy profile. At least two phenotypic subpopulations are discernible based on seizure burden. Early and aggressive treatments for epilepsy in TSC may be best leveraged by targeting specific subgroups based on phenotype severity.
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Project description:BackgroundTo determine if early epilepsy surgery mitigates detrimental effects of refractory epilepsy on development, we investigated surgical and neurodevelopmental outcomes in children with tuberous sclerosis complex who underwent surgery before age two years.MethodsProspective multicenter observational study of 160 children with tuberous sclerosis complex. Surgical outcome was determined for the seizure type targeted by surgery. We obtained Vineland Adaptive Behavior Scales, Second Edition (Vineland-II); Mullen Scales of Early Learning; and Preschool Language Scales, Fifth Edition, at age three, six, nine, 12, 18, 24, and 36 months. Surgical cases were compared with children without seizures, with controlled seizures, and with medically refractory seizures.ResultsNineteen children underwent surgery (median age 17 months, range 3.7 to 21.3), and mean follow-up was 22.8 months (range 12 to 48). Surgical outcomes were favorable in 12 (63%, Engel I-II) and poor in seven (37%, Engel III-IV). Nine (47%) had new or ongoing seizures distinct from those surgically targeted. All children with seizures demonstrated longitudinal decline or attenuated gains in neurodevelopment, the surgical group scoring the lowest. Favorable surgical outcome was associated with increased Mullen Scales of Early Learning receptive and expressive language subscores compared with the medically refractory seizure group. A nonsignificant but consistent pattern of improvement with surgery was seen in all tested domains.ConclusionsThese pilot data show neurodevelopmental gains in some domains following epilepsy surgery. A properly powered, prospective multicenter observational study of early epilepsy surgery is needed, using both surgical and developmental outcome metrics.
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Project description:ObjectivesLittle is known about the evolution of epilepsy in individuals with tuberous sclerosis complex (TSC) in adulthood. This study aims at describing the characteristics of epilepsy in adult TSC patients attending a single multidisciplinary clinic.Materials and methodsWe collected data about epilepsy (age at onset, seizure types, history of infantile spasms (IS), epilepsy diagnosis and outcome), genetic and neuroradiological findings, cognitive outcome and psychiatric comorbidities.ResultsOut of 257 adults with TSC, 183 (71.2%) had epilepsy: 121 (67.2%) were drug-resistant; 59 (32.8%) seizure-free, at a median age of 18 years. 22% of the seizure-free patients (13/59) discontinued medication. Median age at seizure onset was 9 months. Seventy-six patients (41.5%) had a history of IS. TSC2 pathogenic variants (p = 0.018), cortical tubers (p < 0.001) and subependymal nodules (SENs) (p < 0.001) were more frequent in those who developed epilepsy. Cognitive functioning was lower (p < 0.001) and psychiatric disorders more frequent (p = 0.001). We did not find significant differences regarding age, gender, mutation and tubers/SENs in seizure-free vs drug-resistant individuals. Intellectual disability (p < 0.001) and psychiatric disorders (p = 0.004) were more common among drug-resistant patients.ConclusionsEpilepsy in TSC can be a lifelong disorder, but one-third of individuals reach seizure freedom by early adulthood. In the long term, age at epilepsy onset has a crucial role in drug resistance and in developing intellectual disability, both in drug-resistant and drug-sensible patients. Patients with drug-refractory seizures tend to develop psychiatric issues, which should be recognized and adequately treated.
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Project description:Tuberous sclerosis or Bourneville's disease is a rare autosomal dominant disease affecting many organs like the brain, heart, lungs, eyes, kidneys and skin. It is characterized by neurological manifestation like epilepsy, cutaneous changes and the formation of benign lesions in multiple organs. The symptoms are apparent only in late childhood, which limits the early diagnosis in infancy. Here, we report a case of a 15 year old female child with tuberous sclerosis.
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Project description:ObjectiveTo evaluate the long-term benefit and safety of everolimus for the treatment of medically refractory epilepsy in patients with tuberous sclerosis complex (TSC).MethodsEverolimus was titrated over 4 weeks and continued an additional 8 weeks in a prospective, open-label, phase I/II clinical trial design. Participants demonstrating initial benefit continued treatment until study completion (48 months). The primary endpoint was percentage of patients with a ≥50% reduction in seizure frequency compared to baseline. Secondary endpoints assessed absolute seizure frequency, adverse events (AEs), behavior, and quality of life.ResultsOf the 20 participants who completed the initial study phase, 18 continued extended treatment. Fourteen of 18 (78%) participants completed the study, all but 1 of whom reported ≥50% reduction in seizure frequency at 48 months. All participants reported at least 1 AE, the vast majority (94%) of which were graded mild or moderate severity. Improvements in behavior and quality of life were also observed, but failed to achieve statistical significance at 48 months.ConclusionsImproved seizure control was maintained for 4 years in the majority of patients with TSC with medically refractory epilepsy treated with everolimus. Long-term treatment with everolimus is safe and well-tolerated in this population. Everolimus may be a therapeutic option for refractory epilepsy in TSC.Classification of evidenceThis study provides Class IV evidence that for patients with TSC with medically refractory epilepsy everolimus improves seizure control.
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Project description:Tuberous Sclerosis Complex (TSC) is a neurodevelopmental disorder caused by mutations in the TSC1 or TSC2 genes, which encode proteins that negatively regulate mTOR complex 1 (mTORC1) signaling. Current treatment strategies focus on mTOR inhibition with rapamycin and its derivatives. While effective at improving some aspects of TSC, chronic rapamycin inhibits both mTORC1 and mTORC2 and is associated with systemic side-effects. It is currently unknown which mTOR complex is most relevant for TSC-related brain phenotypes. Here we used genetic strategies to selectively reduce neuronal mTORC1 or mTORC2 activity in mouse models of TSC. We find that reduction of the mTORC1 component Raptor, but not the mTORC2 component Rictor, rebalanced mTOR signaling in Tsc1 knock-out neurons. Raptor reduction was sufficient to improve several TSC-related phenotypes including neuronal hypertrophy, macrocephaly, impaired myelination, network hyperactivity, and premature mortality. Raptor downregulation represents a promising potential therapeutic intervention for the neurological manifestations of TSC.
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Project description:BackgroundOur goal was to assess for the first time early vocalizations as precursors to speech in audio-video recordings of infants with tuberous sclerosis complex (TSC).MethodsWe randomly selected 40 infants with TSC from the TSC Autism Center of Excellence Research Network dataset. Using human observers, we analyzed 74 audio-video recordings within a flexible software-based coding environment. During the recordings, infants were engaged in developmental testing. We determined syllables per minute (volubility), the number of consonant-vowel combinations, such as 'ba' (canonical babbling), and the canonical babbling ratio (canonical syllables/total syllables) and compared the data with two groups of typically developing (TD) infants. One comparison group's data had come from a laboratory setting, while the other's had come from all-day Language Environment Analysis recordings at home.ResultsCompared with TD infants in laboratory and all-day Language Environment Analysis recordings, entry into the canonical babbling stage was delayed in the majority of infants with TSC, and the canonical babbling ratio was low (TD mean = 0.346, SE = 0.19; TSC mean = 0.117, SE = 0.023). Volubility level in infants with TSC was less than half that of TD infants (TD mean = 9.82, SE = 5.78; TSC mean = 3.99, SE = 2.16).ConclusionsEntry into the canonical stage and other precursors of speech development were delayed in infants with TSC and may signal poor language and developmental outcomes. Future studies are planned to assess prediction of language and developmental outcomes using these measures in a larger sample and in more precisely comparable recording circumstances.
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Project description:Tuberous sclerosis complex (TSC) is a neurogenetic disorder that affects multiple organ systems, including the heart, kidneys, eyes, skin, and central nervous system. The neurologic manifestations have the highest morbidity and mortality, in particular in children. Clinically, patients with TSC often present with new-onset seizures within the first year of life. TSC-associated epilepsy is often difficult to treat and refractory to multiple antiseizure medications. Refractory TSC-associated epilepsy is associated with increased risk of neurodevelopmental comorbidities, including developmental delay, intellectual disability, autism spectrum disorder, and attention hyperactivity disorder. An increasing body of research suggests that early, effective treatment of TSC-associated epilepsy during critical neurodevelopmental periods can potentially improve cognitive outcomes. Therefore, it is important to treat TSC-associated epilepsy aggressively, whether it be with pharmacological therapy, surgical intervention, and/or neuromodulation. This review discusses current and future pharmacological treatments for TSC-associated epilepsy, as well as the importance of early surgical evaluation for refractory epilepsy in children with TSC and consideration of neuromodulatory interventions in young adults.
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