sirolimus and Seizures

Epileptogenesis in infants with tuberous sclerosis complex (TSC) is a gradual and dynamic process, leading to early onset and difficult-to-treat seizures. Several cellular, molecular and pathophysiologic mechanisms, including mammalian target of rapamycin (mTOR) dysregulation, GABAergic dysfunction and abnormal connectivity, may play a role in this epileptogenic process and may also contribute to the associated developmental encephalopathy. Disease-specific antiseizure medications or drugs targeting the mTOR pathway have proved to be effective in TSC-associated epilepsy. Pre-symptomatic administration of vigabatrin, a GABAergic drug, delays seizure onset and reduces the risk of a subsequent epileptic encephalopathy, such as infantile spasms syndrome or Lennox-Gastaut syndrome. Everolimus, a rapamycin-derived mTOR inhibitor, reduces seizure frequency, especially in younger patients. This evidence suggests that everolimus should be considered early in the course of epilepsy. Future trials are needed to optimize the use of everolimus and determine whether earlier correction of mTOR dysregulation can prevent progression to developmental and epileptic encephalopathies or mitigate their severity in infants with TSC. Clinical trials of several other potential antiseizure drugs (cannabidiol and ganaxolone) that target contributing mechanisms are also underway. This review provides an overview of the different biological mechanisms occurring in parallel and interacting throughout the life course, even beyond the epileptogenic process, in individuals with TSC. These complexities highlight the challenges faced in preventing and treating TSC-related developmental and epileptic encephalopathy.

Topics: Anticonvulsants; Epilepsy; Everolimus; Humans; Infant; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis

Epilepsy is one of the most common and serious brain syndromes and has adverse consequences on a patient's neurobiological, cognitive, psychological, and social wellbeing, thereby threatening their quality of life. Some patients with epilepsy experience poor treatment effects due to the unclear pathophysiological mechanisms of the syndrome. Dysregulation of the mammalian target of the rapamycin (mTOR) pathway is thought to play an important role in the onset and progression of some epilepsies.. This review summarizes the role of the mTOR signaling pathway in the pathogenesis of epilepsy and the prospects for the use of mTOR inhibitors.. The mTOR pathway functions as a vital mediator in epilepsy development through diverse mechanisms, indicating that the it has great potential as an effective target for epilepsy therapy. The excessive activation of mTOR signaling pathway leads to structural changes in neurons, inhibits autophagy, exacerbates neuron damage, affects mossy fiber sprouting, enhances neuronal excitability, increases neuroinflammation, and is closely associated with tau upregulation in epilepsy. A growing number of studies have demonstrated that mTOR inhibitors exhibit significant antiepileptic effects in both clinical applications and animal models. Specifically, rapamycin, a specific inhibitor of TOR, reduces the intensity and frequency of seizures. Clinical studies in patients with tuberous sclerosis complex have shown that rapamycin has the function of reducing seizures and improving this disease. Everolimus, a chemically modified derivative of rapamycin, has been approved as an added treatment to other antiepileptic medicines. Further explorations are needed to evaluate the therapeutic efficacy and application value of mTOR inhibitors in epilepsy.. Targeting the mTOR signaling pathway provides a promising prospect for the treatment of epilepsy.

Topics: Animals; Anticonvulsants; Epilepsy; Humans; MTOR Inhibitors; Quality of Life; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Tuberous sclerosis complex (TSC) is a genetic multisystem disease due to the mutation in one of the two genes TSC1 and TSC2, affecting several organs and systems and carrying a significant risk of early onset and refractory seizures. The pathogenesis of this complex disorder is now well known, with most of TSC-related manifestations being a consequence of the overactivation of the mammalian Target of Rapamycin (mTOR) complex. The discovery of this underlying mechanism paved the way for the use of a class of drugs called mTOR inhibitors including rapamycin and everolimus and specifically targeting this pathway. Rapamycin has been widely used in different animal models of TSC-related epilepsy and proved to be able not only to suppress seizures but also to prevent the development of epilepsy, thus demonstrating an antiepileptogenic potential. In some models, it also showed some benefit on neuropsychiatric manifestations associated with TSC. Everolimus has recently been approved by the US Food and Drug Administration and the European Medical Agency for the treatment of refractory seizures associated with TSC starting from the age of 2 years. It demonstrated a clear benefit when compared to placebo on reducing the frequency of different seizure types and exerting a higher effect in younger children. In conclusion, mTOR cascade can be a potentially major cause of TSC-associated epilepsy and neurodevelopmental disability, and additional research should investigate if early suppression of abnormal mTOR signal with mTOR inhibitors before seizure onset can be a more efficient approach and an effective antiepileptogenic and disease-modifying strategy in infants with TSC.

Topics: Animals; Epilepsy; Everolimus; Humans; Mammals; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis

Epilepsy is a syndrome specified by frequent seizures and is one of the most prevalent neurological conditions, and that one-third of people of epilepsy are resistant to available drugs. Surgery is supposed to be the main treatment for the remedy of multiple drug-resistant epilepsy, but it is a drastic procedure. Advancement in genomic technologies indicates that gene therapy can make such surgery unnecessary. The considerable number of new studies show the significance of mutation in mammalian target of rapamycin pathway, NMDA receptors, GABA receptors, potassium channels and G-protein coupled receptors. Illustration of the meticulous drug in epilepsy targeting new expression of mutations in SCN8A, GRIN2A, GRIN2D and KCNT1 are conferred. Various methods are utilized to express a gene in a precise area of the brain; Transplantation of cells in an ex vivo approach (fetal cells, fibroblasts, immortalized cells), nonviral vector delivery and viral vector delivery like retrovirus, herpes simplex virus adenovirus and adeno-related virus. Gene therapy has thus been explored to generate anti-epileptogenic, anti-seizure and disease-modifying effects. Specific targeting of the epileptogenic region is facilitated by gene therapy, hence sparing the adjacent healthy tissue and decreasing the adverse effects that frequently go hand in hand with antiepileptic medication.

Topics: Animals; Brain; Disease Models, Animal; Epilepsy; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Humans; Metabolic Networks and Pathways; Mutation; Precision Medicine; Seizures; Sirolimus

Sturge-Weber syndrome (SWS) is characterized by facial capillary malformation, leptomeningeal capillary malformations, and choroidal and episcleral vascular malformations. These malformations produce neurologic and ophthalmological symptoms including seizures and glaucoma. A premature male newborn without prenatal diagnosis presented with severe bilateral SWS and was started on systemic sirolimus and aspirin. The patient has remained seizure-free for 23 months and demonstrated an excellent response to pulsed dye laser treatment.

Topics: Administration, Oral; Aspirin; Drug Therapy, Combination; Electroencephalography; Humans; Infant, Newborn; Infant, Premature; Lasers, Dye; Magnetic Resonance Imaging; Male; Port-Wine Stain; Primary Prevention; Prognosis; Risk Assessment; Seizures; Severity of Illness Index; Sirolimus; Sturge-Weber Syndrome; Treatment Outcome

Previous studies have shown potential benefits of rapamycin or rapalogs for treating people with tuberous sclerosis complex. Although everolimus (a rapalog) is currently approved by the FDA (U.S. Food and Drug Administration) and the EMA (European Medicines Agency) for tuberous sclerosis complex-associated renal angiomyolipoma and subependymal giant cell astrocytoma, applications for other manifestations of tuberous sclerosis complex have not yet been established. A systematic review is necessary to establish the clinical value of rapamycin or rapalogs for various manifestations in tuberous sclerosis complex.. To determine the effectiveness of rapamycin or rapalogs in people with tuberous sclerosis complex for decreasing tumour size and other manifestations and to assess the safety of rapamycin or rapalogs in relation to their adverse effects.. Relevant studies were identified by authors from the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, and clinicaltrials.gov. Relevant resources were also searched by the authors, such as conference proceedings and abstract books of conferences, from e.g. the Tuberous Sclerosis Complex International Research Conferences, other tuberous sclerosis complex-related conferences and the Human Genome Meeting. We did not restrict the searches by language as long as English translations were available for non-English reports.Date of the last searches: 14 March 2016.. Randomized or quasi-randomized studies of rapamycin or rapalogs in people with tuberous sclerosis complex.. Data were independently extracted by two authors using standard acquisition forms. The data collection was verified by one author. The risk of bias of each study was independently assessed by two authors and verified by one author.. Three placebo-controlled studies with a total of 263 participants (age range 0.8 to 61 years old, 122 males and 141 females, with variable lengths of study duration) were included in the review. We found high-quality evidence except for response to skin lesions which was judged to be low quality due to the risk of attrition bias. Overall, there are 175 participants in the treatment arm (rapamycin or everolimus) and 88 in the placebo arm. Participants all had tuberous sclerosis complex as proven by consensus diagnostic criteria as a minimum. The quality in the description of the study methods was mixed, although we assessed most domains as having a low risk of bias. Blinding of treatment arms was successfully carried out in all of the studies. However, two studies did not report allocation concealment. Two of the included studies were funded by Novartis Pharmaceuticals.Two studies (235 participants) used oral (systemic) administration of everolimus (rapalog). These studies reported response to tumour size in terms of the number of individuals with a reduction in the total volume of tumours to 50% or more relative to baseline. Significantly more participants in the treatment arm (two studies, 162 participants, high quality evidence) achieved a 50% reduction in renal angiomyolipoma size, risk ratio 24.69 (95% confidence interval 3.51 to 173.41) (P = 0.001). For the sub-ependymal giant cell astrocytoma, our analysis of one study (117 participants, high quality evidence) showed significantly more participants in the treatment arm achieved a 50% reduction in tumour size, risk ratio 27.85 (95% confidence interval 1.74 to 444.82) (P = 0.02). The proportion of participants who showed a skin response from the two included studies analysed was significantly increased in the treatment arms, risk ratio 5.78 (95% confidence interval 2.30 to 14.52) (P = 0.0002) (two studies, 224 participants, high quality evidence). In one study (117 participants), the median change of seizure frequency was -2.9 in 24 hours (95% confidence interval -4.0 to -1.0) in the treatment group versus -4.1 in 24 hour (95% confidence interval -10.9 to 5.8) in the placebo group. In one study, one out of 79 participants in the treatment group versus three of 39 in placebo group had increased blood creatinine levels, while the median percentage change of forced expiratory volume at one second in the treatment arm was -1% compared to -4% in the placebo arm. In one study (117 participants, high quality. We found evidence that oral everolimus significantly increased the proportion of people who achieved a 50% reduction in the size of sub-ependymal giant cell astrocytoma and renal angiomyolipoma. Although we were unable to ascertain the relationship between the reported adverse events and the treatment, participants who received treatment had a similar risk of experiencing adverse events as compared to those who did not receive treatment. Nevertheless, the treatment itself significantly increased the risk of having dose reduction, interruption or withdrawal. This supports ongoing clinical applications of oral everolimus for renal angiomyolipoma and subependymal giant cell astrocytoma. Although oral everolimus showed beneficial effect on skin lesions, topical rapamycin only showed a non-significant tendency of improvement. Efficacy on skin lesions should be further established in future research. The beneficial effects of rapamycin or rapalogs on tuberous sclerosis complex should be further studied on other manifestations of the condition.

Topics: Administration, Oral; Administration, Topical; Angiolipoma; Astrocytoma; Brain Neoplasms; Everolimus; Female; Humans; Immunosuppressive Agents; Kidney Neoplasms; Male; Randomized Controlled Trials as Topic; Seizures; Sirolimus; Skin Diseases; Tuberous Sclerosis; Tumor Burden

The continued occurrence of refractory seizures in at least one-third of children and adults with epilepsy, despite the availability of almost 15 conventional and novel anticonvulsant drugs, speaks to a dire need to develop novel therapeutic approaches. Cellular metabolism, the critical pathway by which cells access and utilize energy, is essential for normal neuronal function. Furthermore, mounting evidence suggests direct links between energy metabolism and cellular excitability. The high-fat, low-carbohydrate ketogenic diet has been used as a treatment for drug-refractory epilepsy for almost a century. Yet, the multitude of alternative therapies to target aspects of cellular metabolism and hyperexcitability is almost untapped. Approaches discussed in this review offer a wide diversity of therapeutic targets that might be exploited by investigators in the search for safer and more effective epilepsy treatments.

Topics: Animals; Anticonvulsants; Caloric Restriction; Diet, Ketogenic; Humans; Ketone Bodies; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

To provide primary care providers with a general overview of the genetic disorder tuberous sclerosis complex (TSC). By understanding the disease mechanism for this genetic condition, providers can effectively care for TSC patients and properly educate families who are affected by TSC. The article also describes the multi-system clinical presentation of the disease to assist primary care providers with an early diagnosis.. Research articles and evidence-based guidelines found through MEDLINE and the World Wide Web.. Using various diagnostic tools and treatment options, providers can offer the multidisciplinary approach needed to manage this disease appropriately. New treatment options, such as rapamycin, may be the future drug of choice in treating TSC.. By following evidence-based clinical practice guidelines, providers can hope to reduce TSC-related morbidity and mortality.

Topics: Child; Child Welfare; Humans; Immunosuppressive Agents; Nervous System Diseases; Pediatric Nursing; Primary Health Care; Seizures; Sirolimus; Tuberous Sclerosis

Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder with variable phenotypic expression, due to a mutation in one of the two genes, TSC1 and TSC2, and a subsequent hyperactivation of the downstream mTOR pathway, resulting in increased cell growth and proliferation. The central nervous system is consistently involved in TSC, with 90% of individuals affected showing structural abnormalities, and almost all having some degree of CNS clinical manifestations, including seizures, cognitive impairment and behavioural problems. TSC is proving to be a particularly informative model for studying contemporary issues in developmental neurosciences. Recent advances in the neurobiology of TSC from molecular biology, molecular genetics, and animal model studies provide a better understanding of the pathogenesis of TSC-related neurological symptoms. Rapamycin normalizes the dysregulated mTOR pathway, and recent clinical trials have demonstrated its efficacy in various TSC manifestations, suggesting the possibility that rapamycin may have benefit in the treatment of TSC brain disease.

Topics: Animals; Behavior; Central Nervous System; Cognition; Disease Models, Animal; Humans; Mice; Rats; RNA, Messenger; Seizures; Sirolimus; Tuberous Sclerosis; Tuberous Sclerosis Complex 1 Protein; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

To determine whether sirolimus, a mechanistic target of rapamycin (mTOR) inhibitor, reduces epileptic seizures associated with focal cortical dysplasia (FCD) type II.. Sixteen patients (aged 6-57 years) with FCD type II received sirolimus at an initial dose of 1 or 2 mg/day based on body weight (FCDS-01). In 15 patients, the dose was adjusted to achieve target trough ranges of 5-15 ng/mL, followed by a 12-week maintenance therapy period. The primary endpoint was a lower focal seizure frequency during the maintenance therapy period. Further, we also conducted a prospective cohort study (RES-FCD) in which 60 patients with FCD type II were included as an external control group.. The focal seizure frequency reduced by 25% in all patients during the maintenance therapy period and by a median value of 17%, 28%, and 23% during the 1-4-, 5-8-, and 9-12-week periods. The response rate was 33%. The focal seizure frequency in the external control group reduced by 0.5%. However, the background characteristics of external and sirolimus-treated groups differed. Adverse events were consistent with those of mTOR inhibitors reported previously. The blood KL-6 level was elevated over time.. The reduction of focal seizures did not meet the predetermined level of statistical significance. The safety profile of the drug was tolerable. The potential for a reduction of focal seizures over time merit further investigations.

Topics: Adolescent; Adult; Child; Epilepsy; Humans; Malformations of Cortical Development, Group I; Middle Aged; Outcome Assessment, Health Care; Protein Kinase Inhibitors; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Young Adult

Tuberous sclerosis complex is a genetic disorder leading to constitutive activation of mammalian target of rapamycin (mTOR) and growth of benign tumours in several organs. In the brain, growth of subependymal giant cell astrocytomas can cause life-threatening symptoms--eg, hydrocephalus, requiring surgery. In an open-label, phase 1/2 study, the mTOR inhibitor everolimus substantially and significantly reduced the volume of subependymal giant cell astrocytomas. We assessed the efficacy and safety of everolimus in patients with subependymal giant cell astrocytomas associated with tuberous sclerosis complex.. In this double-blind, placebo-controlled, phase 3 trial, patients (aged 0-65 years) in 24 centres in Australia, Belgium, Canada, Germany, the UK, Italy, the Netherlands, Poland, Russian Federation, and the USA were randomly assigned, with an interactive internet-response system, in a 2:1 ratio to oral everolimus 4·5 mg/m(2) per day (titrated to achieve blood trough concentrations of 5-15 ng/mL) or placebo. Eligible patients had a definite diagnosis of tuberous sclerosis complex and at least one lesion with a diameter of 1 cm or greater, and either serial growth of a subependymal giant cell astrocytoma, a new lesion of 1 cm or greater, or new or worsening hydrocephalus. The primary endpoint was the proportion of patients with confirmed response--ie, reduction in target volume of 50% or greater relative to baseline in subependymal giant cell astrocytomas. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00789828.. 117 patients were randomly assigned to everolimus (n=78) or placebo (n=39). 27 (35%) patients in the everolimus group had at least 50% reduction in the volume of subependymal giant cell astrocytomas versus none in the placebo group (difference 35%, 95% CI 15-52; one-sided exact Cochran-Mantel-Haenszel test, p<0·0001). Adverse events were mostly grade 1 or 2; no patients discontinued treatment because of adverse events. The most common adverse events were mouth ulceration (25 [32%] in the everolimus group vs two [5%] in the placebo group), stomatitis (24 [31%] vs eight [21%]), convulsion (18 [23%] vs ten [26%]), and pyrexia (17 [22%] vs six [15%]).. These results support the use of everolimus for subependymal giant cell astrocytomas associated with tuberous sclerosis. Additionally, everolimus might represent a disease-modifying treatment for other aspects of tuberous sclerosis.. Novartis Pharmaceuticals.

Topics: Adolescent; Adult; Astrocytoma; Child; Child, Preschool; Double-Blind Method; Everolimus; Female; Fever; Humans; Infant; Male; Oral Ulcer; Seizures; Sirolimus; Stomatitis; Treatment Outcome; Tuberous Sclerosis; Young Adult

Neurosurgical resection is the standard treatment for subependymal giant-cell astrocytomas in patients with the tuberous sclerosis complex. An alternative may be the use of everolimus, which inhibits the mammalian target of rapamycin, a protein regulated by gene products involved in the tuberous sclerosis complex.. Patients 3 years of age or older with serial growth of subependymal giant-cell astrocytomas were eligible for this open-label study. The primary efficacy end point was the change in volume of subependymal giant-cell astrocytomas between baseline and 6 months. We gave everolimus orally, at a dose of 3.0 mg per square meter of body-surface area, to achieve a trough concentration of 5 to 15 ng per milliliter.. We enrolled 28 patients. Everolimus therapy was associated with a clinically meaningful reduction in volume of the primary subependymal giant-cell astrocytoma, as assessed on independent central review (P<0.001 for baseline vs. 6 months), with a reduction of at least 30% in 21 patients (75%) and at least 50% in 9 patients (32%). Marked reductions were seen within 3 months and were sustained. There were no new lesions, worsening hydrocephalus, evidence of increased intracranial pressure, or necessity for surgical resection or other therapy for subependymal giant-cell astrocytoma. Of the 16 patients for whom 24-hour video electroencephalography data were available, seizure frequency for the 6-month study period (vs. the previous 6-month period) decreased in 9, did not change in 6, and increased in 1 (median change, -1 seizure; P=0.02). The mean (±SD) score on the validated Quality-of-Life in Childhood Epilepsy questionnaire (on which scores can range from 0 to 100, with higher scores indicating a better quality of life) was improved at 3 months (63.4±12.4) and 6 months (62.1±14.2) over the baseline score (57.8±14.0). Single cases of grade 3 treatment-related sinusitis, pneumonia, viral bronchitis, tooth infection, stomatitis, and leukopenia were reported.. Everolimus therapy was associated with marked reduction in the volume of subependymal giant-cell astrocytomas and seizure frequency and may be a potential alternative to neurosurgical resection in some cases, though long-term studies are needed. (Funded by Novartis; ClinicalTrials.gov number, NCT00411619.).

Topics: Administration, Oral; Adolescent; Adult; Angiofibroma; Anticonvulsants; Astrocytoma; Brain Neoplasms; Child; Child, Preschool; Cognition; Drug Therapy, Combination; Everolimus; Facial Neoplasms; Female; Humans; Intracellular Signaling Peptides and Proteins; Male; Prospective Studies; Protein Serine-Threonine Kinases; Quality of Life; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Young Adult

The efficacy of the mechanistic target of rapamycin inhibitor, sirolimus, was recently reported for patients more than 6 years of age by Kato et al. We evaluated the efficacy and safety of sirolimus in a 2-year-old patient with recurrent focal seizures with impaired consciousness after focal cortical dysplasia (FCD) type IIa resection.. The patient was a 2-year-old girl who had recurrent seizures after undergoing FCD resection at 4 months of age. The initial dose of sirolimus was 0.5 mg/day and was gradually increased using the trough blood concentration before oral administration as an index, and evaluation was performed at 92 weeks.. The trough blood level of sirolimus was increased to 6.1 ng/mL and maintenance therapy was started at 40 weeks. Focal seizures with impairment of consciousness with tonic extension of the limbs decreased. No critically serious adverse events occurred.. Sirolimus was effective against epileptic seizures from FCD type II even for a child under 5 years of age. There were no critically serious adverse events and administration could be continued.

Topics: Child; Child, Preschool; Epilepsy; Epilepsy, Generalized; Female; Focal Cortical Dysplasia; Humans; Magnetic Resonance Imaging; Malformations of Cortical Development; Seizures; Sirolimus

Tuberous sclerosis complex is a rare autosomal dominant genetic disorder that affects multiple organ systems, primarily affecting the central nervous system. It develops with a pathogenic mutation in tumour suppressor genes i.e. Tuberous Sclerosis Complex 1 or Tuberous Sclerosis Complex 2 which codes for protein hamartin and tuberin leading to unopposed hyperactivation of the mammalian target of the rapamycin signalling pathway. It presents with a triad of facial angiofibroma, intellectual disability, and epilepsy. We present a case of a 17-month female toddler with abnormal body movement with loss of consciousness and later developing into generalised jerky movements. On magnetic resonance imaging, a diagnosis of tuberous sclerosis was made. The patient underwent symptomatic management with anti-epileptic. As seizures in these cases are subtle, they remain undiagnosed for a long time leading to delays in management and developing refractory seizures.. angiofibroma; case reports; seizures; tuberous sclerosis; tumor suppressor gene.

Topics: Angiofibroma; Female; Humans; Infant; Seizures; Sirolimus; Tuberous Sclerosis; Tumor Suppressor Proteins

Sudden Unexpected Death in Epilepsy (SUDEP) is primarily linked with the cardiac irregularities that occur due to recurrent seizures. Our previous studies found a role of mTOR pathway activation in seizures-linked cardiac damage in a rat model. In continuation to the earlier work, the present study was devised to explore the role of rapamycin (mTOR inhibitor and clinically used immunosuppressive agent) in a zebrafish kindling model and associated cardiac damage. Adult zebrafish were incubated with increasing concentrations of rapamycin (1, 2 and, 4 μM), followed by pentylenetetrazole (PTZ) exposure to record seizure latency and severity. In another experiment, zebrafish were subjected to a standardized PTZ kindling protocol. The kindled fish were treated daily with rapamycin for up to 25 days, along with PTZ to record seizure severity. At the end, zebrafish heart was excised for carbonylation assay, gene expression, and protein quantification studies. In the acute PTZ convulsion test, treatment with rapamycin showed a significant increase in seizure latency and decreased seizure severity without any change in seizure incidence. Treatment with rapamycin also reduced the severity of seizures in kindled fish. The cardiac expressions of gpx, nppb, kcnh2, scn5a, mapk8, stat3, rps6 and ddit were decreased, whereas the levels of trxr2 and beclin 1 were increased following rapamycin treatment in kindled fish. Furthermore, rapamycin treatment also decreased p-mTOR expression and protein carbonyls level in the fish cardiac tissue. The present study concluded that rapamycin reduces seizures and associated cardiac damage by inhibiting mTOR activation in the zebrafish kindling model.

Topics: Animals; Epilepsy; Mammals; Rats; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Zebrafish

The piriform cortex, known as area tempestas, has a high propensity to trigger limbic epileptic seizures. Recent studies on human patients indicate that a resection containing the piriform cortex produces a marked improvement in patients suffering from intractable limbic seizures. This calls for looking back at the pharmacological and anatomical data on area tempestas. Within the piriform cortex, status epilepticus can be induced by impairing the desensitization of AMPA receptors. The mechanistic target of rapamycin complex1 (mTORC1) is a promising candidate.. The present perspective aims to link the novel role of the piriform cortex with recent evidence on the modulation of AMPA receptors under the influence of mTORC1. This is based on recent evidence and preliminary data, leading to the formulation of interaction between mTORC1 and AMPA receptors to mitigate the onset of long-lasting, self-sustaining, neurotoxic status epilepticus.. The perspective grounds its method on recent literature along with the actual experimental procedure to elicit status epilepticus from the piriform cortex and the method to administer the mTORC1 inhibitor rapamycin to mitigate seizure expression and brain damage.. The available and present perspectives converge to show that rapamycin may disrupt the seizure circuitry initiated in the piriform cortex to mitigate seizure duration, severity, and brain damage.. The perspective provides a novel scenario to understand refractory epilepsy and selfsustaining status epilepticus. It is expected to provide a beneficial outcome in patients suffering from temporal lobe epilepsy.

Topics: Humans; Mechanistic Target of Rapamycin Complex 1; Receptors, AMPA; Seizures; Sirolimus; Status Epilepticus; TOR Serine-Threonine Kinases

The most frequent genetic cause of focal epilepsies is variations in the GAP activity toward RAGs 1 complex genes DEP domain containing 5 (DEPDC5), nitrogen permease regulator 2-like protein (NPRL2) and nitrogen permease regulator 3-like protein (NPRL3). Because these variations are frequent and associated with a broad spectrum of focal epilepsies, a unique pathology categorized as GATORopathy can be conceptualized. Animal models recapitulating the clinical features of patients are essential to decipher GATORopathy. Although several genetically modified animal models recapitulate DEPDC5-related epilepsy, no models have been reported for NPRL2- or NPRL3-related epilepsies. Here, we conditionally deleted Nprl2 and Nprl3 from the dorsal telencephalon in mice [Emx1cre/+; Nprl2f/f (Nprl2-cKO) and Emx1cre/+; Nprl3f/f (Nprl3-cKO)] and compared their phenotypes with Nprl2+/-, Nprl3+/- and Emx1cre/+; Depdc5f/f (Depdc5-cKO) mice. Nprl2-cKO and Nprl3-cKO mice recapitulated the major abnormal features of patients-spontaneous seizures, and dysmorphic enlarged neuronal cells with increased mechanistic target of rapamycin complex 1 signaling-similar to Depdc5-cKO mice. Chronic postnatal rapamycin administration dramatically prolonged the survival period and inhibited seizure occurrence but not enlarged neuronal cells in Nprl2-cKO and Nprl3-cKO mice. However, the benefit of rapamycin after withdrawal was less durable in Nprl2- and Nprl3-cKO mice compared with Depdc5-cKO mice. Further studies using these conditional knockout mice will be useful for understanding GATORopathy and for the identification of novel therapeutic targets.

Topics: Animals; Disease Models, Animal; Epilepsies, Partial; Epilepsy; GTPase-Activating Proteins; Membrane Transport Proteins; Mice; Mice, Knockout; Mutation; Nitrogen; Seizures; Sirolimus; Telencephalon; Tumor Suppressor Proteins

Mutations in nitrogen permease regulator-like 3 (NPRL3), a component of the GATOR1 complex within the mTOR pathway, are associated with epilepsy and malformations of cortical development. Little is known about the effects of NPRL3 loss on neuronal mTOR signalling and morphology, or cerebral cortical development and seizure susceptibility. We report the clinical phenotypic spectrum of a founder NPRL3 pedigree (c.349delG, p.Glu117LysFS; n = 133) among Old Order Mennonites dating to 1727. Next, as a strategy to define the role of NPRL3 in cortical development, CRISPR/Cas9 Nprl3 knockout in Neuro2a cells in vitro and in foetal mouse brain in vivo was used to assess the effects of Nprl3 knockout on mTOR activation, subcellular mTOR localization, nutrient signalling, cell morphology and aggregation, cerebral cortical cytoarchitecture and network integrity. The NPRL3 pedigree exhibited an epilepsy penetrance of 28% and heterogeneous clinical phenotypes with a range of epilepsy semiologies, i.e. focal or generalized onset, brain imaging abnormalities, i.e. polymicrogyria, focal cortical dysplasia or normal imaging, and EEG findings, e.g. focal, multi-focal or generalized spikes, focal or generalized slowing. Whole exome analysis comparing a seizure-free group (n = 37) to those with epilepsy (n = 24) to search for gene modifiers for epilepsy did not identify a unique genetic modifier that explained the variability in seizure penetrance in this cohort. Nprl3 knockout in vitro caused mTOR pathway hyperactivation, cell soma enlargement and the formation of cellular aggregates seen in time-lapse videos that were prevented with the mTOR inhibitors rapamycin or torin1. In Nprl3 knockout cells, mTOR remained localized on the lysosome in a constitutively active conformation, as evidenced by phosphorylation of ribosomal S6 and 4E-BP1 proteins, even under nutrient starvation (amino acid-free) conditions, demonstrating that Nprl3 loss decouples mTOR activation from neuronal metabolic state. To model human malformations of cortical development associated with NPRL3 variants, we created a focal Nprl3 knockout in foetal mouse cortex by in utero electroporation and found altered cortical lamination and white matter heterotopic neurons, effects which were prevented with rapamycin treatment. EEG recordings showed network hyperexcitability and reduced seizure threshold to pentylenetetrazol treatment. NPRL3 variants are linked to a highly variable clinical phenotype which we propose

Topics: Animals; Epilepsy; GTPase-Activating Proteins; Humans; Malformations of Cortical Development; Mice; Neurons; Seizures; Sirolimus; TOR Serine-Threonine Kinases

Topics: Alzheimer Disease; Cognitive Dysfunction; Humans; Memory Disorders; Seizures; Sirolimus

To evaluate whether sirolimus treatment could relieve the later burden of new-onset seizures in patients with tuberous sclerosis complex (TSC) prior to epilepsy.. A real-world matched case-control study was nested in another registry cohort study. Infants with TSC (<12 months old) without seizures whose parents agreed on sirolimus treatment for other symptoms were eligible for inclusion to the early sirolimus (ES) group. These patients were enrolled from 2015 to 2018. Controls in the late sirolimus (LS) group were matched from the registry cohort database for 2015-2018. Age and genotype were used as the initial stratifying criteria and other symptoms as the greedy matching criteria at a matching ratio of 1:4. None of the preventive drugs were introduced before seizure onset or before 2 years of age in the LS group. Both groups were followed up until June 2020. The primary objective was a comparison of the characteristics of the first seizure between the two groups. The secondary objective was the assessment of the final seizure status at the endpoint.. There were 42 and 168 patients with TSC in the ES and LS groups, respectively. Early sirolimus treatment significantly reduced the seizure onset, especially in the patients aged <6 months. The mean onset-age was significantly delayed by sirolimus treatment (11.34±7.93 months vs. 6.94±6.03 months, P<0.001). The subtype of seizures that benefited the most was spastic (onset) seizures (all were infantile spasms) [5/42 (11.90%) vs. 73/168 (43.45%), P<0.001]; these seizures were either eliminated or alleviated. The sirolimus treatment addition prior to seizures was more effective than its addition after seizures in reducing drug-resistant epilepsy [10/42 (23.81%) vs. 70/147 (47.62%), P=0.004].. Early sirolimus treatment for TSC effectively modified the disease by preventing infantile spasms, delaying seizure onset, and relieving its severity. The anti-epileptogenic effect of sirolimus may be time- and dose-dependent.

Topics: Case-Control Studies; Child, Preschool; Cohort Studies; Epilepsy; Humans; Infant; Registries; Seizures; Sirolimus; Spasms, Infantile; Tuberous Sclerosis

To assess the safety of inactivated coronavirus 2019 disease (COVID-19) vaccine in tuberous sclerosis complex (TSC) patients with epilepsy.. All patients with epilepsy were selected from Efficacy and Safety of Sirolimus in Pediatric Patients with Tuberous Sclerosis (ESOSPIT) project and younger than 17 years old. The patients were treated with mTOR inhibitors (rapamycin). A total of 44 patients who completed the two-dose inactivated COVID-19 vaccine between July 7, 2021, and January 1, 2022, were enrolled.. The median age of seizure onset was 23 months. About two-thirds of patients have focal seizures. Thirty-three patients use antiseizure medications. The mean duration of rapamycin treatment was 55.59 ± 18.42 months. Adverse reactions within 28 days after injection occurred in 11 patients (25%), all were under 12 years old. Injection site pain was the most reported event (20.45%), which was mild in severity and improved within one day. All patients had no seizure-related changes after vaccination.. This study shows that the inactivated COVID-19 vaccine was well tolerated and safe in TSC patients with epilepsy, as well as for those treated with mTOR inhibitors.

Topics: Adolescent; Child; Child, Preschool; COVID-19; COVID-19 Vaccines; Epilepsy; Humans; Infant; MTOR Inhibitors; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis

Tuberous sclerosis complex (TSC) is a genetic disorder involving a variety of physical manifestations, and is associated with epilepsy and multiple serious neuropsychiatric symptoms. These symptoms are collectively known as TSC-associated neuropsychiatric disorders (TAND), which is a severe burden for patients and their families. Overactivation of the mechanistic target of rapamycin complex 1 (mTORC1) by mutations in TSC1 or TSC2 is thought to cause TSC, and mTORC1 inhibitors such as sirolimus and everolimus are reported to be effective against various tumor types of TSC. However, there are various reports on the effect of mTORC1 inhibitor therapy on TAND in patients with TSC, which may or may not be effective. In our previous investigations, we generated TSC2 conditional knockout mice (Mitf-Cre, Tsc2 KO; Tsc2 cKO). These mice developed spontaneous epileptic activity. In the current study, we further analyzed the detailed behaviors of Tsc2 cKO mice and confirmed that they exhibited phenotypes of TAND as well as epileptic seizures, indicating that Tsc2 cKO mice are a useful model for TAND. Furthermore, the olfactory bulb and piriform cortex caused epilepsy and TAND in Tsc2 cKO mice, and neurodegeneration was observed. Immunohistology and immunophenotypic analysis of cells, and quantitative RT-PCR suggested that changes in microglial polarity were involved in the onset of TSC epilepsy and neuropsychiatric symptoms. Although the effect of mTORC1 inhibitors on TAND has not been established, the results of this study might help elucidate the mechanism of TAND pathogenesis and suggest that sirolimus may be a valuable therapeutic tool for TAND.

Topics: Animals; Epilepsy; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Knockout; Microglia; Seizures; Sirolimus; Tuberous Sclerosis

In previous studies, we found that dynorphin exerts antiepileptic effect by activating the kappa opioid receptor (KOR). However, the role of neuronal autophagy in dynorphin/KOR-mediated antiepileptic is still unclear. This study aimed to investigate the molecular mechanism of dynorphin's antiepileptic effect by inhibiting autophagy and reducing neuronal apoptosis. Here, a pilocarpine-induced rat model of epilepsy was established and hippocampal neurons were treated with Mg

Topics: Animals; Anticonvulsants; Apoptosis; Autophagy; Biotin; Dynorphins; Epilepsy; Green Fluorescent Proteins; Mammals; Pilocarpine; Rats; Rats, Sprague-Dawley; Receptors, Opioid, kappa; RNA, Messenger; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Facial angiofibroma is the most predominant cutaneous manifestation of tuberous sclerosis complex (TSC), a rare autosomal dominant genetic disorder impacting the mechanistic target of rapamycin (mTOR). Facial angiofibroma can bleed spontaneously, impair eyesight, and cause aesthetic disfiguration causing psychological and social stress. To date, there is little or no evidence on the demographics, and other TSC features associated with facial angiofibroma or the use of mTOR inhibitor for the management of facial angiofibroma. This is a retrospective study of TSC Alliance's Natural History Database aimed to characterize facial angiofibroma and to evaluate features associated with a higher risk of facial angiofibroma or the use of topical mTOR inhibitors for the management of facial angiofibroma. Data in the NHD was obtained from 18 clinical sites in the US since 2006.. Of the 2240 patients, 2088 patients were enrolled in the US and data from 2057 patients were included in this analysis. The mean (median) age of overall TSC patients was 22.4 (19.0) years. A total of 69 patients were ≤ 5 years of age. Facial angiofibroma was noted in 1329 (64.6%) patients with TSC. Patients with facial angiofibroma were older on average (Mean: 25.9 [median, 23.0] vs. 16.0 [12.4 years] years, p < 0.0001). In patients with vs. without facial angiofibroma, TSC2 mutation (38.9% vs. 34.8%) was more common than TSC1 mutation (12.3% vs. 18.1%), and the incidence rate of most of the other TSC-related manifestations was significantly higher in patients with facial angiofibroma. Majority of patients had focal seizures (72.8% vs. 60.7%), followed by angiomyolipoma (63.7% vs. 21.8%) and renal cysts (59.4% vs. 33.5%). The age groups, 11-17 (odds ratio [OR], 2.53) and 18-45 years (5.98), TSC2 mutation (1.31), focal seizures (1.50), ADHD (1.47) angiomyolipoma (2.79), and renal cysts (2.63) were significantly associated with a higher risk of facial angiofibroma based on multivariate logistic regression. Abrasive or laser therapy was used by 17.1% and 2.6% patients, respectively. Topical mTOR inhibitor use was noted for 329 (24.8%) patients with facial angiofibroma. Overall systemic mTOR inhibitor use was observed in 399 (30.0%) patients for management of one or more TSC manifestations. Use of systemic mTOR inhibitor for facial angiofibroma was noted for 163 (12.3%) patients, among whom only 9 (0.7%) patients used exclusively for the management of facial angiofibroma. Of the patients with facial angiofibroma, 44.6% did not receive any treatment. Significantly higher use of topical mTOR inhibitor was associated with the 11-17 years age group (OR, 1.67), anxiety (1.57), angiomyolipoma (1.51), and renal cysts (1.33).. The presence of TSC2 mutations and most other TSC-related manifestations was significantly higher in patients with facial angiofibroma. About one-fourth of patients with facial angiofibroma used a topical mTOR inhibitor and use of systemic mTOR inhibitor for the management of facial angiofibroma or for the other manifestations was noted for 30.0%. About 44.6% of patients did not receive any treatment for the management of facial angiofibroma.

Topics: Adult; Angiomyolipoma; Humans; Immunosuppressive Agents; Kidney Diseases, Cystic; Kidney Neoplasms; MTOR Inhibitors; Retrospective Studies; Seizures; Sirolimus; Tuberous Sclerosis; United States; Young Adult

The mechanistic target of the rapamycin (mTOR) pathway is involved in cortical development. However, the efficacy of mTOR inhibitors in malformations of cortical dysplasia (MCD) outside of the tuberous sclerosis complex is unknown. We selected the MCD rat model with prenatal MAM exposure to test the efficacy of mTOR inhibitors in MCDs. We explored the early cortical changes of mTOR pathway protein expression in rats aged P15. We also monitored the early treatment effect of the mTOR inhibitor, rapamycin, on N-methyl-D-aspartate (NMDA)-induced spasms at P15 and their behavior in the juvenile stage. In vivo MR spectroscopy was performed after rapamycin treatment and compared with vehicle controls. There was no difference in mTORC1 pathway protein expression between MAM-exposed MCD rats and controls at P15, and prolonged treatment of rapamycin had no impact on NMDA-induced spasms despite poor weight gain. Prenatal MAM-exposed juvenile rats treated with rapamycin showed increased social approaching and freezing behavior during habituation. MR spectroscopy showed altered neurometabolites, including Gln, Glu+Gln, Tau, and Cr. Despite behavioral changes and in vivo neurometabolic alteration with early prolonged rapamycin treatment, rapamycin had no effect on spasms susceptibility in prenatal MAM-exposed infantile rats with MCD without mTORC1 activation. For MAM-exposed MCD rats without mTORC1 activation, treatment options outside of mTOR pathway inhibitors should be explored.

Topics: Animals; Female; Malformations of Cortical Development; Mechanistic Target of Rapamycin Complex 1; N-Methylaspartate; Pregnancy; Rats; Seizures; Sirolimus; Spasm; TOR Serine-Threonine Kinases

Topics: Aminopyridines; Animals; Apoptosis; Cell Line; Cytokines; Hippocampus; Imidazoles; Immunosuppressive Agents; Male; Membrane Potential, Mitochondrial; Mice; Mice, Inbred C57BL; Morpholines; Neuroinflammatory Diseases; Oxidative Stress; Phosphoinositide-3 Kinase Inhibitors; Quinolines; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Hemimegalencephaly (HME) is a rare hamartomatous congenital malformation of the brain characterized by dysplastic overgrowth of either one of the cerebral hemispheres. HME is associated with early onset seizures, abnormal neurological findings, and with subsequent cognitive and behavioral disabilities. Seizures associated with HME are often refractory to antiepileptic medications. Hemispherectomy is usually necessary to provide effective seizure control. The exact etiology of HME is not fully understood, but involves a disturbance in early brain development and likely involves genes responsible for patterning and symmetry of the brain. We present a female newborn who had refractory seizures due to HME. Whole genome sequencing revealed a novel, likely pathogenic, maternally inherited, 3Kb deletion encompassing exon 5 of the NPRL3 gene (chr16:161898-164745x1). The NPRL3 gene encodes for a nitrogen permease regulator 3-like protein, a subunit of the GATOR complex, which regulates the mTOR signaling pathway. A trial of mTOR inhibitor drug, Sirolimus, did not improve her seizure control. Functional hemispherectomy at 3 months of age resulted in total abatement of clinical seizures.

Topics: Brain; Epilepsy; Female; Genetic Predisposition to Disease; GTPase-Activating Proteins; Hemimegalencephaly; Humans; Infant, Newborn; Seizures; Sirolimus; TOR Serine-Threonine Kinases

Epilepsy is one of the most common neurological disorders, with individuals having an increased susceptibility of seizures in the first few years of life, making children at risk of developing a multitude of cognitive and behavioral comorbidities throughout development. The present study examined the role of PI3K/Akt/mTOR pathway activity and neuroinflammatory signaling in the development of autistic-like behavior following seizures in the neonatal period. Male and female C57BL/6J mice were administered 3 flurothyl seizures on postnatal (PD) 10, followed by administration of minocycline, the mTOR inhibitor rapamycin, or a combined treatment of both therapeutics. On PD12, isolation-induced ultrasonic vocalizations (USVs) of mice were examined to determine the impact of seizures and treatment on communicative behaviors, a component of the autistic-like phenotype. Seizures on PD10 increased the quantity of USVs in female mice and reduced the amount of complex call types emitted in males compared to controls. Inhibition of mTOR with rapamycin significantly reduced the quantity and duration of USVs in both sexes. Changes in USVs were associated with increases in mTOR and astrocyte levels in male mice, however, three PD10 seizures did not result in enhanced proinflammatory cytokine expression in either sex. Beyond inhibition of mTOR activity by rapamycin, both therapeutics did not demonstrate beneficial effects. These findings emphasize the importance of differences that may exist across preclinical seizure models, as three flurothyl seizures did not induce as drastic of changes in mTOR activity or inflammation as observed in other rodent models.

Topics: Animals; Convulsants; Disease Models, Animal; Epilepsy; Female; Flurothyl; Immunologic Factors; Male; Mice; Mice, Inbred C57BL; Minocycline; MTOR Inhibitors; Seizures; Sex Factors; Sirolimus; Vocalization, Animal

Epileptic seizures are core symptoms in focal cortical dysplasia (FCD), a disease that often develops in infancy. Such seizures are refractory to conventional antiepileptic drugs (AED) and temporarily disappear in response to AED in only 17% of patients. Currently, surgical resection is an important option for the treatment of epileptic seizures in FCD. In 2015, Korean and Japanese groups independently reported that FCD is caused by somatic mosaic mutation of the MTOR gene in the brain tissue. Based on these results we decided to test a novel treatment using sirolimus, an mTOR inhibitor, for epileptic seizures in patients with FCD type II. A single arm open-label clinical trial for FCD type II patients is being conducted in order to evaluate the efficacy and safety of sirolimus. The dose of sirolimus is fixed for the first 4 weeks and dose adjustment is achieved to maintain a blood level of 5 to 15 ng/mL during 8 to 24 weeks after initiation of administration, and it is kept within this level during a maintenance therapy period of 12 weeks. Primary endpoint is a reduction in the rate of incidence of focal seizures (including focal to bilateral tonic-clonic seizures) per 28 days during the maintenance therapy period from the observation period. To evaluate the frequency of epileptic seizures, registry data will be used as an external control group. We hope that the results of this trial will lead to future innovative treatments for FCD type II patients.

Topics: Clinical Trials as Topic; Epilepsy; Humans; Malformations of Cortical Development; Malformations of Cortical Development, Group I; Seizures; Sirolimus; TOR Serine-Threonine Kinases

Numerous studies have reported that epilepsy causes memory deficits. The present study was aimed at studying the effect of rapamycin against the memory deficiency of the pentylenetetrazole (PTZ)-kindled animal model of epilepsy. In the present experiment, we randomly chose thirty male rats from the species of Wistar and categorized them in groups of control and experiment (6 for each group). The groups of experiment received the injection of rapamycin (0.5, 1 and 2 mg/kg) intraperitoneally (i.p.) and the group of control received normal saline (0.9%) treatment. Through the PTZ's sub-threshold dose (35 mg kg

Topics: Animals; Brain; Disease Models, Animal; Kindling, Neurologic; Male; Memory; Memory Disorders; Neurons; Pentylenetetrazole; Rats; Rats, Wistar; Seizures; Sirolimus

Infantile spasms may evolve into persistent epilepsies including Lennox-Gastaut syndrome. We compared adult epilepsy outcomes in models of infantile spasms due to structural etiology (multiple-hit model) or focal cortical inflammation and determined the anti-epileptogenic effects of pulse-rapamycin, previously shown to stop spasms in multiple-hit rats.. Spasms were induced in 3-day-old male rats via right intracerebral doxorubicin/lipopolysaccharide (multiple-hit model) infusions. Controls and sham rats were used. Separate multiple-hit rats received pulse-rapamycin or vehicle intraperitoneally between postnatal days 4 and 6. In adult mice, video-EEG (electroencephalography) scoring for seizures and sleep and histology were done blinded to treatment.. Motor-type seizures developed in 66.7% of multiple-hit rats, usually from sleep, but were reduced in the pulse-rapamycin-treated group (20%, p = .043 vs multiple-hit) and rare in other groups (0-9.1%, p < .05 vs multiple-hit). Spike-and-wave bursts had a slower frequency in multiple-hit rats (5.4-5.8Hz) than in the other groups (7.6-8.3Hz) (p < .05); pulse rapamycin had no effect on the hourly spike-and-wave burst rates in adulthood. Rapamycin, however, reduced the time spent in slow-wave-sleep (17.2%), which was increased in multiple-hit rats (71.6%, p = .003). Sham rats spent more time in wakefulness (43.7%) compared to controls (30.6%, p = .043). Multiple-hit rats, with or without rapamycin treatment, had right more than left corticohippocampal, basal ganglia lesions. There was no macroscopic pathology in the other groups.. Structural corticohippocampal/basal ganglia lesions increase the risk for post-infantile spasms epilepsy, Lennox-Gastaut syndrome features, and sleep dysregulation. Pulse rapamycin treatment for infantile spasms has anti-epileptogenic effects, despite the structural lesions, and decreases the time spent in slow wave sleep.

Topics: Animals; Disease Models, Animal; Electroencephalography; Epilepsy; Lennox Gastaut Syndrome; Male; Mice; Rats; Seizures; Sirolimus; Spasm

Topics: Child; Humans; Immunosuppressive Agents; Seizures; Sirolimus; Tuberous Sclerosis

Topics: Anticonvulsants; Child; Humans; Pharmaceutical Preparations; Seizures; Sirolimus; Tuberous Sclerosis

Pre-ischemic hyperglycemia increases the occurrence of post-ischemic seizures both in experimental and clinical settings. The underlying mechanisms are not fully delineated; however, activation of mammalian target of rapamycin (mTOR) has been shown to be engaged in the pathogenesis of epilepsy, in which seizures are a regular occurrence. Therefore, we wanted to explore specifically the capacity of an mTOR inhibitor, rapamycin, in preventing post-ischemic seizures in hyperglycemic rats and to explore the underlying molecular mechanisms. The results showed that none of the rats in the sham control, EG ischemic, or within 3 h of I/R in hyperglycemic ischemic groups experienced seizures. Generalized tonic-clonic seizures were observed in all 8/8 of hyperglycemic ischemic rats at 16 h of I/R. Treatment with rapamycin successfully blocked post-ischemic seizures in 7/8 hyperglycemic ischemic animals. Rapamycin also lessened the neuronal death extraordinarily in hyperglycemic ischemic animals as revealed by histopathological studies. Protein analysis revealed that transient ischemia resulted in increases in p-mTOR and p-S6, especially in the hippocampi of the hyperglycemic ischemic rats. Rapamycin treatment completely blocked mTOR activation. Furthermore, hyperglycemic ischemia induced a much prominent rise of p-ERK1/2 both in the cortex and the hippocampi compared with EG counterparts; whereas rapamycin suppressed it. We conclude that the development of post-ischemic seizures in the hyperglycemic animals may be associated with activations of mTOR and ERK1/2 pathways and that rapamycin treatment inhibited the post-ischemic seizures effectively by suppressing the mTOR and ERK1/2 signaling.

Topics: Animals; Anticonvulsants; Brain Ischemia; Cell Death; Cerebral Cortex; Cytosol; Disease Models, Animal; Hippocampus; Hyperglycemia; Male; MAP Kinase Signaling System; Neurons; Phosphorylation; Rats; Rats, Wistar; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Patients with mammalian target of rapamycin (mTOR)-dependent malformations of cortical development (MCDs) associated with seizures display hyperperfusion and increased vessel density of the dysmorphic cortical tissue. Some studies have suggested that the vascular defect occurred independently of seizures. Here, we further examined whether hypervascularization occurs in animal models of global and focal MCD with and without seizures, and whether it is sensitive to the mTOR blocker, rapamycin, that is approved for epilepsy treatment in tuberous sclerosis complex.. We used two experimental models of mTOR-dependent MCD consisting of conditional transgenic mice containing Tsc1. Blood vessels in both the focal and global MCDs of postnatal day 14 mice displayed significant increase in vessel density, branching index, total vessel length, and decreased tissue lacunarity. In addition, rapamycin treatment (0.5 mg/kg, every 2 days) partially rescued vessel abnormalities in the focal MCD model, but it did not ameliorate the vessel abnormalities in the global MCD model that required higher rapamycin dosage for a partial rescue.. Here, we identified hypervascularization in mTOR-dependent MCD in the absence of seizures in young mice, suggesting that increased angiogenesis occurs during development in parallel to alterations in corticogenesis. In addition, a predictive functional outcome is that dysplastic neurons forming MCD will have better access to oxygen and metabolic supplies via their closer proximity to blood vessels. Finally, the difference in rapamycin sensitivity between a focal and global MCD suggest that rapamycin treatment will need to be titrated to match the type of MCD.

Topics: Animals; Blood Vessels; Cell Size; Dendrites; Electroporation; Female; Malformations of Cortical Development; Mice; Mice, Transgenic; Neovascularization, Pathologic; Neurons; Plasmids; Pregnancy; Seizures; Sirolimus; Somatosensory Cortex; TOR Serine-Threonine Kinases; Tuberous Sclerosis

To report the genotype-phenotype characteristics, demographic features and clinical outcome of Omani patients with congenital hyperinsulinism (CHI). Methods: We retrospectively analyzed the clinical, biochemical, genotypical, phenotypical characteristics and outcomes of  children with CHI who were presented to the pediatric endocrine team in the Royal Hospital, Muscat, Oman between January 2007 and December 2016. Results: Analysis of 25 patients with CHI genetically revealed homozygous mutation in ABCC8 in 23 (92%) patients and 2 patients (8%) with compound heterozygous mutation in ABCC8. Fifteen (60%) patients underwent subtotal pancreatectomy as medical therapy failed and 2 (8%) patients showed response to medical therapy. Three patients expired during the neonatal period, 2 had cardiomyopathy and sepsis, and one had sepsis and severe metabolic acidosis. Out of the 15 patients who underwent pancreatectomy, 6 developed diabetes mellitus, 6 continued to have hypoglycemia and required medical therapy and one had pancreatic exocrine dysfunction post-pancreatectomy, following up with gastroenterology clinic and was placed on pancreatic enzyme supplements, while 2 patients continued to have hypoglycemia and both had abdominal MRI and 18-F-fluoro-L-DOPA positron emission tomography scan (PET-scan), that showed  persistent of the disease and started on medical therapy. Conclusion:  Mutation in ABCC8 is the most common cause of CHI and reflects the early age of presentation. There is a need for early diagnosis and appropriate therapeutic strategy.

Topics: Apnea; Child, Preschool; Congenital Hyperinsulinism; Diabetes Mellitus; Enzyme Replacement Therapy; Exocrine Pancreatic Insufficiency; Female; Gastrointestinal Agents; Heterozygote; Homozygote; Humans; Hypoglycemia; Infant; Infant, Newborn; Lethargy; Male; Mutation; Octreotide; Oman; Pancreatectomy; Peptides, Cyclic; Postoperative Complications; Retrospective Studies; Seizures; Sirolimus; Somatostatin; Sulfonylurea Receptors; Treatment Outcome

Topics: Animals; Azabicyclo Compounds; Blood-Brain Barrier; Cell Line, Tumor; Cell Proliferation; Humans; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Models, Molecular; Phosphatidylinositol 3-Kinases; Protein Conformation; Pyridines; Rats; Seizures; Triazines

Autophagy alterations have been observed in a variety of neurological disorders, however, very few studies have focused on autophagy alterations in epilepsy. The ketogenic diet (KD) likely ameliorates neuronal loss in several seizure models. However, whether this neuroprotective function occurs via starvation-induced autophagy and its prevalence in chronic kindled seizures remains unknown. The aim of this study was to determine the role of autophagy following seizure under KD, and the potential mechanism involved. Pentylenetetrazol (PTZ)-kindled rats, which were fed a Normal diet (ND) or KD, were pretreated with intraventricular infusions of saline, autophagy inducer rapamycin (RAP), or inhibitor 3-methyladenine (3-MA). KD alleviated seizure severity, decreased the number of Fluoro-jade B (FJB)-positive cells in the hippocampus of kindled rats. These effects were abolished by 3-MA pretreatment. RAP pretreatment did not affect seizure severity, but decreased the number of FJB-positive cells in ND group. KD decreased the percentage of damaged mitochondria in kindled group. Hippocampal Beclin-1 was increased by KD in vehicle group. The autophagy proteins Atg5, Beclin-1 and the ratio of microtubule-associated protein 1 light chain 3 (LC3) II to LC3-I in kindled KD-fed rats were higher, and the autophagy substrate P62 was lower than those in the kindled ND-fed rats, indicating an increase in autophagy following KD. Pretreatment with RAP increased the level of LC3-II/LC3-I, and pretreatment with 3-MA increased the level of P62 in KD-fed rats. To further clarify the mechanism of autophagy protection, the levels of key mitochondria related molecules were examed. The results showed that mitochondrial cytochrome c was up-regulated, cytosolic cytochrome c and the downstream cleaved caspase-3 was down-regulated in KD-fed rats, indicating a decrease in mitochondrial apoptosis. Taken together, our results indicated that KD activates autophagic pathways and reduces brain injury during PTZ-kindled seizures. The neuroprotective effect of KD is likely exerted via a reduction of mitochondrial cytochrome c release.

Topics: Adenine; Animals; Apoptosis; Autophagy; Caspase 3; Cytochromes c; Diet, Ketogenic; Epilepsy; Hippocampus; Male; Mitochondria; Neurons; Neuroprotective Agents; Pentylenetetrazole; Rats; Rats, Sprague-Dawley; Seizures; Sirolimus

Stroke is considered an underlying etiology of the development of seizures. Stroke leads to glucose and oxygen deficiency in neurons, resulting in brain dysfunction and injury. Mild hypothermia is a therapeutic strategy to inhibit stroke‑induced seizures, which may be associated with the regulation of energy metabolism of the brain. Mammalian target of rapamycin (mTOR) signaling and solute carrier family 2, facilitated glucose transporter member (GLUT)‑1 are critical for energy metabolism. Furthermore, mTOR overactivation and GLUT‑1 deficiency are associated with genetically acquired seizures. It has been hypothesized that mTOR and GLUT‑1 may additionally be involved in seizures elicited by stroke. The present study established global cerebral ischemia (GCI) models of rats. Convulsive seizure behaviors frequently occurred during the first and the second days following GCI, which were accompanied with seizure discharge reflected in the EEG monitor. Expression of phosphor (p)‑mTOR and GLUT‑1 were upregulated in the cerebral cortex and hippocampus, as evidenced by immunohistochemistry and western blot analyses. Mild hypothermia and/or rapamycin (mTOR inhibitor) treatments reduced the number of epileptic attacks, seizure severity scores and seizure discharges, thereby alleviating seizures induced by GCI. Mild hypothermia and/or rapamycin treatments reduced phosphorylation levels of mTOR and the downstream effecter p70S6 in neurons, and the amount of GLUT‑1 in the cytomembrane of neurons. The present study revealed that mTOR is involved in stroke‑induced seizures and the anti‑seizure effect of mild hypothermia. The role of GLUT‑1 in stroke‑elicited seizures appears to be different from the role in seizures induced by other reasons. Further studies are necessary in order to elucidate the exact function of GLUT-1 in stroke‑elicited seizures.

Topics: Animals; Biomarkers; Brain Ischemia; Disease Models, Animal; Electroencephalography; Glucose; Glucose Transporter Type 1; Hypothermia, Induced; Immunohistochemistry; Male; Neurons; Rats; Seizures; Severity of Illness Index; Signal Transduction; Sirolimus; Stroke; TOR Serine-Threonine Kinases

The mTOR signaling pathway has emerged as a possible therapeutic target for epilepsy. Clinical trials have shown that mTOR inhibitors such as everolimus reduce seizures in tuberous sclerosis complex patients with intractable epilepsy. Furthermore, accumulating preclinical data suggest that mTOR inhibitors may have anti-seizure or anti-epileptogenic actions in other types of epilepsy. However, the chronic use of rapalogs such as everolimus is limited by poor tolerability, particularly by immunosuppression, poor brain penetration and induction of feedback loops which might contribute to their limited therapeutic efficacy. Here we describe two novel, brain-permeable and well tolerated small molecule 1,3,5-triazine derivatives, the catalytic mTORC1/C2 inhibitor PQR620 and the dual pan-PI3K/mTOR inhibitor PQR530. These derivatives were compared with the mTORC1 inhibitors rapamycin and everolimus as well as the anti-seizure drugs phenobarbital and levetiracetam. The anti-seizure potential of these compounds was determined by evaluating the electroconvulsive seizure threshold in normal and epileptic mice. Rapamycin and everolimus only poorly penetrated into the brain (brain:plasma ratio 0.0057 for rapamycin and 0.016 for everolimus). In contrast, the novel compounds rapidly entered the brain, reaching brain:plasma ratios of ∼1.6. Furthermore, they significantly decreased phosphorylation of S6 ribosomal protein in the hippocampus of normal and epileptic mice, demonstrating effective mTOR inhibition. PQR620 and PQR530 significantly increased seizure threshold at tolerable doses. The effect of PQR620 was more marked in epileptic vs. nonepileptic mice, matching the efficacy of levetiracetam. Overall, the novel compounds described here have the potential to overcome the disadvantages of rapalogs for treatment of epilepsy and mTORopathies directly connected to mutations in the mTOR signaling cascade.

Topics: Animals; Anticonvulsants; Azabicyclo Compounds; Blood-Brain Barrier; Catalysis; Electroshock; Enzyme Inhibitors; Epilepsy; Everolimus; Female; Hippocampus; Levetiracetam; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Morpholines; Phenobarbital; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Pyridines; Ribosomal Proteins; Seizures; Sirolimus; Triazines

Topics: Adolescent; Child; Epilepsy; Everolimus; Humans; Seizures; Sirolimus; Tuberous Sclerosis

The purpose of this study was to evaluate the long-term results of eight cases diagnosed with tuberous sclerosis complex (TSC) and receiving rapamycin therapy because of epileptic seizures and/or accompanying TSC findings.. Rapamycin therapy was initiated at a dose of 1.5 mg/m. Four girls and four boys aged 4-16 years at the start of rapamycin therapy and now aged 9-24 years were evaluated. Duration of rapamycin therapy was 1-5 years, and the monitoring period after commencement of rapamycin therapy lasted 5-8 years. Positive effects were observed at 9-12 months in three out of six cases of renal angiomyolipoma (AML) and in the second year of treatment in one. An increase in AML dimensions was observed in three cases after treatment was stopped. Seizure control was established in the first year of rapamycin therapy in all cases. An increased frequency of seizures was observed in three cases after the second year of treatment. No seizure recurrence was determined in the second year of treatment with rapamycin in five out of eight cases. Recurrence of seizure was observed in 6-12 months after the discontinuation of rapamycin in three cases.. Rapamycin therapy exhibits positive effects on epileptic seizures in cases of TSC in 1-2 years but these positive effects on seizure control of rapamycin therapy decline after the second year. Larger case series are still needed to determine the duration and effectiveness of treatment in childhood.

Topics: Adolescent; Adult; Child; Electroencephalography; Epilepsy; Female; Humans; Male; Neoplasm Recurrence, Local; Retrospective Studies; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Young Adult

Astrocytes have been implicated in epileptogenesis and seizure-induced brain injury. Pathological studies reveal a variety of structural abnormalities in astrocytes, such as vacuolization and astrogliosis. While in vivo imaging methods have demonstrated rapid changes in astrocytes under a variety of physiological and pathological conditions, the acute effects of seizures on astrocyte morphology in vivo and corresponding mechanisms of seizure-induced astrocytic injury have not been documented. In this study, we utilized in vivo two-photon imaging to directly monitor the acute structural effects of kainate-induced seizures on cortical astrocytes. Kainate seizures cause an immediate, but transient, vacuolization of astrocytes, followed over several days by astrogliosis. These effects are prevented by pre- or post-treatment with rapamycin, indicating the mTOR pathway is involved in mediating seizure-induced astrocyte injury. These finding have clinical implications for mechanisms of seizure-induced astrocyte injury and potential therapeutic applications with mTOR inhibitors.

Topics: Animals; Astrocytes; Disease Models, Animal; Kainic Acid; Mice; Seizures; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Vacuoles

De novo mutations in specific mTOR pathway genes cause brain overgrowth in the context of intellectual disability (ID). By analyzing 101 mMTOR-related genes in a large ID patient cohort and two independent population cohorts, we show that these genes modulate brain growth in health and disease. We report the mTOR activator gene RHEB as an ID gene that is associated with megalencephaly when mutated. Functional testing of mutant RHEB in vertebrate animal models indicates pathway hyperactivation with a concomitant increase in cell and head size, aberrant neuronal migration, and induction of seizures, concordant with the human phenotype. This study reveals that tight control of brain volume is exerted through a large community of mTOR-related genes. Human brain volume can be altered, by either rare disruptive events causing hyperactivation of the pathway, or through the collective effects of common alleles.

Topics: Animals; Brain; Cell Movement; Cell Size; Cells, Cultured; Humans; Intellectual Disability; Megalencephaly; Mutation; Neurons; Organ Size; Ras Homolog Enriched in Brain Protein; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Zebrafish

Microglia is responsible for neuroinflammation, which may aggravate brain injury in diseases like epilepsy. Mammalian target of rapamycin (mTOR) kinase is related to microglial activation with subsequent neuroinflammation. In the present study, rapamycin and everolimus, both as mTOR inhibitors, were investigated in models of kainic acid (KA)-induced seizure and lipopolysaccharide (LPS)-induced neuroinflammation.. Everolimus was significantly more effective than rapamycin in inhibiting iNOS and mTOR signaling pathways in both models of neuroinflammation (LPS) and seizure (KA). Everolimus significantly attenuated the mRNA expression of iNOS by LPS and nitrite production by KA and LPS than that by rapamycin. Only everolimus attenuated the mRNA expression of mTOR by LPS and KA treatment. In the present study, we also found that the modulation of mTOR under LPS and KA treatment was not mediated by Akt pathway but was primarily mediated by ERK phosphorylation, which was more significantly attenuated by everolimus. This inhibition of ERK phosphorylation and microglial activation in the hippocampus by everolimus was also confirmed in KA-treated mice.. Rapamycin and everolimus can block the activation of inflammation-related molecules and attenuated the microglial activation. Everolimus had better efficacy than rapamycin, possibly mediated by the inhibition of ERK phosphorylation. Taken together, mTOR inhibitor can be a potential pharmacological target of anti-inflammation and seizure treatment.

Topics: Animals; Convulsants; Everolimus; Immunosuppressive Agents; Inflammation; Kainic Acid; Mice; Microglia; Seizures; Sirolimus; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) has been demonstrated to mediate multidrug resistance in various tumors by inducing P-glycoprotein (P-gp) overexpression. Here, we investigated the correlation between the mTOR pathway and P-gp expression in pharmacoresistant epilepsy. Temporal cortex specimens were obtained from patients with refractory mesial temporal lobe epilepsy (mTLE) and age-matched controls who underwent surgeries at West China Hospital of Sichuan University between June 2014 and May 2015. We established a rat model of epilepsy kindled by coriaria lactone (CL) and screened pharmacoresistant rats (non-responders) using phenytoin. Non-responders were treated for 4 weeks with vehicle only or with the mTOR pathway inhibitor rapamycin at doses of 1, 3, and 6 mg/kg. Western blotting and immunohistochemistry were used to detect the expression of phospho-S6 (P-S6) and P-gp at different time points (1 h, 8 h, 1 day, 3 days, 1 weeks, 2 weeks, and 4 weeks) after the onset of treatment. Overexpression of P-S6 and P-gp was detected in both refractory mTLE patients and non-responder rats. Rapamycin showed an inhibitory effect on P-S6 and P-gp expression 1 week after treatment in rats. In addition, the expression levels of P-S6 and P-gp in the 6 mg/kg group were significantly lower than those in the 1 mg/kg or the 3 mg/kg group at the same time points (all P < 0.05). Moreover, rapamycin decreased the duration and number of CL-induced seizures, as well as the stage of non-responders (all P < 0.05). The current study indicates that the mTOR signaling pathway plays a critical role in P-gp expression in drug-resistant epilepsy. Inhibition of the mTOR pathway by rapamycin may be a potential therapeutic approach for pharmacoresistant epilepsy.

Topics: Adult; Animals; Anticonvulsants; ATP Binding Cassette Transporter, Subfamily B, Member 1; Case-Control Studies; Drug Resistant Epilepsy; Female; Humans; Lactones; Male; Phenytoin; Rats; Rats, Sprague-Dawley; Seizures; Sirolimus; TOR Serine-Threonine Kinases

Focal cortical dysplasia (FCD), a local malformation of cortical development, is the most common cause of pharmacoresistant epilepsy associated with life-long neurocognitive impairments. It remains unclear whether neuronal misplacement is required for seizure activity. Here we show that dyslamination and white matter heterotopia are not necessary for seizure generation in a murine model of type II FCDs. These experimental FCDs generated by increasing mTOR activity in layer 2/3 neurons of the medial prefrontal cortex are associated with tonic-clonic seizures and a normal survival rate. Preventing all FCD-related defects, including neuronal misplacement and dysmorphogenesis, with rapamycin treatments from birth eliminates seizures, but seizures recur after rapamycin withdrawal. In addition, bypassing neuronal misplacement and heterotopia using inducible vectors do not prevent seizure occurrence. Collectively, data obtained using our new experimental FCD-associated epilepsy suggest that life-long treatment to reduce neuronal dysmorphogenesis is required to suppress seizures in individuals with FCD.

Topics: Animals; Cell Movement; Cognitive Dysfunction; Disease Models, Animal; Female; Gene Expression Regulation; Genes, Reporter; Green Fluorescent Proteins; Humans; Male; Malformations of Cortical Development; Mice; Neurons; Prefrontal Cortex; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; White Matter

BACKGROUND The aim of this study was to determine whether activation of mammalian target of rapamycin (mTOR) is a key epileptogenic mechanism in the development of alcohol-related seizure. MATERIAL AND METHODS C57BL/6 mice were administered 10% ethanol in drinking water for 9 weeks. Video-electroencephalography (EEG) monitoring was then used to assess seizure frequency after alcohol and rapamycin treatment. In addition, mouse neuroblastoma NG108-15 cells were treated ethanol for 3 days and subsequently treated with AKT inhibitor LY294002 for 2-12 h. The in vitro kinase assay was performed for determining mTOR activity. Western blot analysis was used to determine the expression of P-AKT, P-S6K, and P-S6. RESULTS Long-term ethanol treatment markedly increased the seizure frequency of C57/BL6 mice over time. Moreover, ethanol treatment increased the expression level of P-S6 over time. Ethanol-induced seizure can be reversed by rapamycin. In addition, the in vitro kinase assay showed mTOR activity was activated by ethanol. Compared with NG108-15 cells treated without both ethanol and LY294002, ethanol increased the expression level of P-AKT, P-S6K, and P-S6, whereas LY294002 had opposite effects on expression levels of these proteins. CONCLUSIONS Our findings indicate that long-term alcohol intake increases the risk of epilepsy via activation of mTOR signaling. Moreover, ethanol-induced mTOR activation may be dependent on the AKT-mTOR signaling pathway. The key molecules involved in AKT-mTOR signaling pathway may serve as potential targets in the treatment of epilepsy.

Topics: Animals; Chromones; Enzyme Inhibitors; Epilepsy; Ethanol; Mice; Mice, Inbred C57BL; Morpholines; Phosphorylation; Proto-Oncogene Proteins c-akt; Risk Factors; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

Epilepsy and other neurological deficits are common, disabling manifestations of the genetic disorder, tuberous sclerosis complex (TSC). Brain inflammation has been implicated in contributing to epileptogenesis in acquired epilepsy due to brain injury, but the potential role of inflammatory mechanisms in genetic epilepsies is relatively unexplored. In this study, we investigated activation of inflammatory mediators and tested the effects of anti-inflammatory treatment on epilepsy in the Tsc1-GFAP conditional knock-out mouse model of TSC (Tsc1(GFAP)CKO mice). Real-time quantitative RT-PCR, immunohistochemistry, and Western blotting demonstrated increased expression of specific cytokines and chemokines, particularly IL-1β and CXCL10, in the neocortex and hippocampus of Tsc1(GFAP)CKO mice, which was reversed by treatment with a mammalian target of rapamycin complex 1 (mTORC1) inhibitor. Double-labeling immunohistochemical studies indicated that the increased IL-1β was localized primarily to astrocytes. Importantly, the increase in inflammatory markers was also observed in astrocyte culture in vitro and at 2 weeks of age in Tsc1(GFAP)CKO mice before the onset of epilepsy in vivo, indicating that the inflammatory changes were not secondary to seizures. Epicatechin-3-gallate, an inhibitor of IL-1β and CXCL10, at least partially reversed the elevated cytokine and chemokine levels, reduced seizure frequency, and prolonged survival of Tsc1(GFAP)CKO mice. These findings suggest that mTOR-mediated inflammatory mechanisms may be involved in epileptogenesis in the genetic epilepsy, TSC.

Topics: Animals; Anti-Inflammatory Agents; Catechin; Encephalitis; Hippocampus; Inflammation Mediators; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Knockout; Multiprotein Complexes; Neocortex; Neuroglia; Seizures; Sirolimus; Survival Analysis; TOR Serine-Threonine Kinases; Tuberous Sclerosis; Tuberous Sclerosis Complex 1 Protein; Tumor Suppressor Proteins

The mTORC1 complex integrates different inputs from intracellular and extracellular signals to control various cellular processes. Therefore, any disruption in the mTORC1 pathway could promote different neurological disorders. mTORC1 overactivation has been verified in different genetic and acquired epilepsy animal models. Therefore, inhibitors of this complex could have both antiepileptogenic and antiseizure effects. In our study, we investigated the effects of rapamycin pretreatment on pentylenetetrazole (PTZ)-induced seizures in zebrafish. Our results have shown that the latency to reach the tonic-clonic stage (stage III) of progressive behavioral alterations shown during PTZ-induced seizures was prolonged in larval (7days post fertilization, 7dpf), juvenile (45days post fertilization, 45dpf) and adult (6-8months) zebrafish after pretreatment with rapamycin. Furthermore, rapamycin pretreatment did not alter the locomotor activity in zebrafish. Therefore, the results obtained in our study indicate that rapamycin pretreatment is an important mechanism to control the progress of seizures in zebrafish throughout different developmental stages (larval, juvenile, and adult). Taken as a whole, our data support that rapamycin has immediate antiseizure effects and could be a potential alternative therapy for seizure control in epilepsy.

Topics: Animals; Anticonvulsants; Convulsants; Disease Models, Animal; Larva; Mechanistic Target of Rapamycin Complex 1; Motor Activity; Multiprotein Complexes; Pentylenetetrazole; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases; Zebrafish; Zebrafish Proteins

Cannabidiol (CBD), a major non-psychotomimetic constituent of Cannabis sativa, has therapeutic potential for certain psychiatric and neurological disorders. Studies in laboratory animals and limited human trials indicate that CBD has anticonvulsant and neuroprotective properties. Its effects against cocaine neurotoxicity, however, have remained unclear. Thus, the present study tested the hypothesis that CBD protects against cocaine-induced seizures and investigated the underlying mechanisms. CBD (30 mg/kg) pre-treatment increased the latency and reduced the duration of cocaine (75 mg/kg)-induced seizures in mice. The CB1 receptor antagonist, AM251 (1 and 3mg/kg), and the CB2 receptor antagonist, AM630 (2 and 4 mg/kg), failed to reverse this protective effect, suggesting that alternative mechanisms are involved. Synaptosome studies with the hippocampus of drug-treated animals revealed that cocaine increases glutamate release, whereas CBD induces the opposite effect. Finally, the protective effect of this cannabinoid against cocaine-induced seizure was reversed by rapamycin (1 and 5mg/kg), an inhibitor of the mammalian target of rapamycin (mTOR) intracellular pathway. In conclusion, CBD protects against seizures in a model of cocaine intoxication. These effects possibly occur through activation of mTOR with subsequent reduction in glutamate release. CBD should be further investigated as a strategy for alleviating psychostimulant toxicity.

Topics: Anesthetics, Local; Animals; Antiemetics; Cannabidiol; Cocaine; Disease Models, Animal; Dose-Response Relationship, Drug; Glutamic Acid; Immunosuppressive Agents; Indoles; Male; Mice; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

We are reporting on a 13.5-year-old girl with tuberous sclerosis complex (TSC) who was treated with everolimus because of giant cell astrocytoma and bilateral angiomyolipoma. She suffered from pharmacoresistant partial epilepsy with clusters of tonic and tonic-clonic seizures. Treatment with carbamazepine and sulthiame had led to a stable situation for more than 2.5 years. The dosage of everolimus had to be increased and refractory status epilepticus followed after 12 days. In the absence of any other possible cause, we believe that the status epilepticus was provoked by everolimus. So far, only a few cases of possible seizure aggravation by everolimus have been reported. The clinical relevance of possible negative effects in epileptic patients remains unclear. Similar observations should be documented and reported.

Topics: Adolescent; Antineoplastic Agents; Astrocytoma; Epilepsies, Partial; Everolimus; Female; Humans; Seizures; Sirolimus; Status Epilepticus; Tuberous Sclerosis

The acute activation of the dopamine D1-like receptors (D1R) is involved in a plethora of functions ranging from increased locomotor activity to the facilitation of consolidation, storage, and retrieval of memories. Although much less characterized, epileptiform activities, usually triggered by disruption of the glutamate and GABA balance, have also been reported to involve the dopaminergic transmission. Using a combination of biochemical, immunohistochemical, electrophysiological, and behavioral approaches we have investigated the consequences of repeated stimulation of D1R using the selective D1R-like agonist SKF81297. Here, we report that repeated systemic administration of SKF81297 induces kindled seizures in mice. These seizure episodes parallel the hyperactivation of the mTOR signaling in the hippocampus, leading to disrupted long-term potentiation (LTP) in the dentate gyrus (DG) and altered recognition memories. The mTOR inhibitor rapamycin delays the development of SKF81297-induced kindled seizures, and rescues LTP in the DG and object recognition. Our results show that repeated stimulation of D1R is sufficient to induce generalized seizures leading to the overactivation of mTOR signaling, disrupted hippocampal plasticity, and impaired long-term recognition memories. This work highlights the interest of mTOR inhibitors as therapeutic strategies to reverse plasticity and cognitive deficits.

Topics: Animals; Benzazepines; Cerebral Cortex; Dentate Gyrus; Dopamine Agonists; Excitatory Postsynaptic Potentials; Extracellular Signal-Regulated MAP Kinases; Long-Term Potentiation; Male; Memory Disorders; Mice, Inbred C57BL; Motor Activity; Neuroprotective Agents; Receptors, Dopamine D1; Recognition, Psychology; Seizures; Signal Transduction; Sirolimus; Tissue Culture Techniques; TOR Serine-Threonine Kinases

To evaluate the therapeutic effect and safety of rapamycin in treatment of children with tuberous sclerosis complex (TSC) complicated with epilepsy.. This was an open-label, prospective, self-controlled study. From Sep. 2011 to Sep. 2013, 52 patients with the diagnosis of tuberous sclerosis complicated with epilepsy receiving rapamycin treatment for at least 24 weeks were enrolled.. Of the 52 children, 34 were male and 18 female. The median age at onset of epilepsy was 4.8 months (4 days-49 months), the median age for treatment with rapamycin was 27 months (4.5-172.5 months). Ten children had a family history of TSC. In 24 children TSC gene detection was carried out, among whom TSC1 mutation was detected in 4 cases and TSC2 mutation in 20. Before rapamycin therapy, 59.62%, (31/52) patients took more than 3 antiepileptic drugs, of whom 10 cases even took more than 5 kinds of antiepileptic drugs. Fifty-two patients received rapamycin treatment for 24 weeks, seizure free rate was 25.00% (13 cases), the total effective rate was 73.08% (38 cases); 31 cases received treatment for 48 weeks, seizure free 6 cases, total effective 23 cases; 17 cases accepted treatment for 72 weeks, seizure free 5 cases, total effective 13 cases; 12 cases received treatment for 96 weeks, seizure free 3 cases, total effective 9 cases. With the decrease of seizure attacks, use of antiepileptic drug types were reduced simultaneously, they had a negative correlation. Before rapamycin therapy, the average frequency of seizures was 70.27 times/d, the number of antiepileptic drug kinds was 1.30. After 24, 48, 72, 96 weeks' treatment, the average seizure frequency was reduced to 1.94-2.80 times /d and the antiepileptic drugs were reduced to 0.83-0.97 kinds. On every visit during the follow-up, blood and urine routine tests, liver and kidney function test showed no abnormality in the 52 cases. The drug dosage was 1 mg/(m(2)×d), average 0.7 mg/d (0.35-1.20 mg/d). Blood concentrations of rapamycin remained below 10 µg/L (average 6.5 µg/L). The main side effect was oral ulcer which happened in 23.08% (12/52). The oral ulcer would disappeared 2-3 days later. 17.31% (9/52 cases) had upper respiratory infection.. Rapamycin was effective in children with tuberous sclerosis and epilepsy with few adverse reactions. The daily dose of rapamycin for children patients is 1 mg/m(2), which has a certain effect on seizures and a good safety profile.

Topics: Adolescent; Anticonvulsants; Child; Child, Preschool; Epilepsy; Female; Humans; Infant; Male; Prospective Studies; Seizures; Sirolimus; Treatment Outcome; Tuberous Sclerosis

Homeostatic plasticity is characterized by compensatory changes in synaptic strength and intrinsic membrane properties in response to chronic changes in neuronal activity. Neonatal seizures are a naturally occurring source of neuronal overactivation and can lead to long-term epilepsy and cognitive deficits. Using a rodent model of hypoxia-induced neonatal seizures that results in a persistent increase in AMPA receptor (AMPAR) function in hippocampal CA1 pyramidal neurons, we aimed to determine whether there was any evidence of an opposing endogenous homeostatic antiepileptic response. Given that this model results in long-term epilepsy, we also examined mechanisms whereby this homeostasis fails. Whole-cell patch-clamp recordings from neurons in slices removed at intervals following seizure onset revealed an initial up-regulation of AMPAR function that was followed by a transient dynamic attenuation of this enhancement by 48-72 h, although AMPAR function was still increased compared with nonseizure control baseline. This secondary down-regulation of enhanced AMPAR function was coincident with a marked transient increase in expression and function of the Polo-like kinase 2 (PLK2), which has previously been implicated in homeostatic down-regulation of neuronal excitability in cell/slice culture models. The effects were transient and at 1 wk AMPAR function once again became up-regulated, simultaneous with a decrease in PLK2 expression and function. This negative regulation was mediated by subacute postseizure increases in mammalian target of rapamycin (mTOR). Application of the mTOR inhibitor rapamycin prevented post-hypoxic seizure impairment of homeostasis, suggesting that homeostatic plasticity mechanisms may be potentially modifiable therapeutic targets in epileptogenesis.

Topics: Animals; Animals, Newborn; Anti-Bacterial Agents; CA1 Region, Hippocampal; Male; Mechanistic Target of Rapamycin Complex 1; Microdissection; Multiprotein Complexes; Neuronal Plasticity; Protein Serine-Threonine Kinases; Proteins; Pyramidal Cells; Rats; Rats, Long-Evans; Receptors, AMPA; Seizures; Sirolimus; Time Factors; Tissue Culture Techniques; TOR Serine-Threonine Kinases

A rare neurodevelopmental disorder in the Old Order Mennonite population called PMSE (polyhydramnios, megalencephaly, and symptomatic epilepsy syndrome; also called Pretzel syndrome) is characterized by infantile-onset epilepsy, neurocognitive delay, craniofacial dysmorphism, and histopathological evidence of heterotopic neurons in subcortical white matter and subependymal regions. PMSE is caused by a homozygous deletion of exons 9 to 13 of the LYK5/STRADA gene, which encodes the pseudokinase STRADA, an upstream inhibitor of mammalian target of rapamycin complex 1 (mTORC1). We show that disrupted pathfinding in migrating mouse neural progenitor cells in vitro caused by STRADA depletion is prevented by mTORC1 inhibition with rapamycin or inhibition of its downstream effector p70 S6 kinase (p70S6K) with the drug PF-4708671 (p70S6Ki). We demonstrate that rapamycin can rescue aberrant cortical lamination and heterotopia associated with STRADA depletion in the mouse cerebral cortex. Constitutive mTORC1 signaling and a migration defect observed in fibroblasts from patients with PMSE were also prevented by mTORC1 inhibition. On the basis of these preclinical findings, we treated five PMSE patients with sirolimus (rapamycin) without complication and observed a reduction in seizure frequency and an improvement in receptive language. Our findings demonstrate a mechanistic link between STRADA loss and mTORC1 hyperactivity in PMSE, and suggest that mTORC1 inhibition may be a potential treatment for PMSE as well as other mTOR-associated neurodevelopmental disorders.

Topics: Animals; Blotting, Western; Cell Movement; Cells, Cultured; Central Nervous System Diseases; Cytarabine; Female; Humans; Imidazoles; Immunohistochemistry; Mechanistic Target of Rapamycin Complex 1; Mice; Multiprotein Complexes; Piperazines; Pregnancy; Seizures; Sirolimus; TOR Serine-Threonine Kinases

Mammalian target of rapamycin (mTOR) is a protein kinase that senses nutrient availability, trophic factors support, cellular energy level, cellular stress, and neurotransmitters and adjusts cellular metabolism accordingly. Adequate mTOR activity is needed for development as well as proper physiology of mature neurons. Consequently, changes in mTOR activity are often observed in neuropathology. Recently, several groups reported that seizures increase mammalian target of rapamycin (mTOR) kinase activity, and such increased activity in genetic models can contribute to spontaneous seizures. However, the current knowledge about the spatiotemporal pattern of mTOR activation induced by proconvulsive agents is rather rudimentary. Also consequences of insufficient mTOR activity on a status epilepticus are poorly understood. Here, we systematically investigated these two issues. We showed that mTOR signaling was activated by kainic acid (KA)-induced status epilepticus through several brain areas, including the hippocampus and cortex as well as revealed two waves of mTOR activation: an early wave (2 h) that occurs in neurons and a late wave that predominantly occurs in astrocytes. Unexpectedly, we found that pretreatment with rapamycin, a potent mTOR inhibitor, gradually (i) sensitized animals to KA treatment and (ii) induced gross anatomical changes in the brain.

Topics: Animals; Astrocytes; Brain; Cell Death; Cell Nucleus; Hippocampus; Kainic Acid; Male; Neurons; Phosphorylation; Phosphoserine; Rats; Rats, Wistar; Ribosomal Protein S6; Seizures; Signal Transduction; Sirolimus; Spatio-Temporal Analysis; Status Epilepticus; Subcellular Fractions; TOR Serine-Threonine Kinases

Several signaling pathways are believed to be involved in the epileptogenic process that triggers the subsequent changes in the brain causing epilepsy. The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that in the brain, regulates several important physiological functions such as neuronal development and synaptic plasticity, and also seems to be involved in many pathologies, including epilepsy and psychiatric disorders. Previous work in animal models of both genetic and acquired generalized convulsive epilepsies, has suggested that modulators of the mTOR signaling pathway may have beneficial neuroprotective and antiepileptogenic effects. Here, we investigated for the first time, the effect of some treatment schedules (i.e. early chronic, sub-chronic and acute) with the specific mTOR inhibitor rapamycin, on the development of absence seizures and seizure parameters as well as depressive-like behavior in WAG/Rij rats, a genetic model of absence epilepsy, epileptogenesis and mild-depression comorbidity. In addition, we studied the possible interaction between rapamycin treatment and the effects of bacterial lipopolysaccharide (LPS) endotoxin administration, which is known to aggravate absence seizures through generation of increased neuroinflammatory responses. We found that rapamycin (early chronic treatment for 17 weeks, starting at P45) exhibited clear antiepileptogenic properties also in this animal epilepsy model; however, this effect was accompanied by unexpected prodepressant effects. Both acute and sub-chronic (7 day) treatments also had anti-absence properties, but the sub-chronic treatment produced contrasting antidepressant properties in the WAG/Rij rats that were not seen in control Wistar rats. The rapamycin/LPS co-administration studies showed that rapamycin blocked or prevented the LPS-dependent increase in absence seizures, suggesting an anti-inflammatory-like protective action. In conclusion, we have demonstrated a novel antiepileptogenic effect of rapamycin in a well-established animal model of absence epilepsy, and we suggest that this effect may be mediated by the inhibition of inflammatory processes that are developed in the brain of these specific animals during epileptogenesis and during seizures. Our experiments here suggest new insights into this intriguing field, which deserves to be further explored. This article is part of the Special Issue entitled 'New Targets and Approaches to the Treatment of Epilepsy'.

Topics: Animals; Anticonvulsants; Behavior, Animal; Depression; Electroencephalography; Epilepsy, Absence; Feeding Behavior; Immunohistochemistry; Lipopolysaccharides; Motor Activity; Neurosurgical Procedures; Rats; Rats, Wistar; Seizures; Sirolimus; Sucrose; Swimming; TOR Serine-Threonine Kinases

Approximately 30% of all epilepsy cases are acquired. At present there is no effective strategy to stop epilepsy development after the precipitating insult. Recent data from experimental models pointed to the mTOR pathway, which can be potently inhibited by rapamycin. However, data on the antiepileptic and antiepileptogenic properties of rapamycin are conflicting. Therefore, we tested whether rapamycin post-treatment influences epileptogenesis in the amygdala stimulation model of temporal lobe epilepsy in rats. Animals were treated with rapamycin (6mg/kg) or vehicle daily for 2 wks, beginning 24h after stimulation. Sham-operated animals were treated with rapamycin or vehicle but were not stimulated. Animals were video-EEG monitored to detect spontaneous seizures. Animals were sacrificed 4 wks later and brains were collected for Timm staining. There were no significant differences in the number of stimulated rats developing epilepsy; latency to first spontaneous seizure; number of seizures, or seizure frequency in epileptic animals. The area occupied by mossy fibers was significantly increased in stimulated vs. sham-operated animals but was not different in animals treated with rapamycin vs. vehicle. Collectively, our data suggest that the antiepileptic or antiepileptogenic action of rapamycin is not a universal phenomenon and might be limited to certain experimental models or experimental conditions.

Topics: Amygdala; Animals; Disease Models, Animal; Epilepsy, Temporal Lobe; Male; Mossy Fibers, Hippocampal; Rats; Rats, Sprague-Dawley; Seizures; Sirolimus; TOR Serine-Threonine Kinases

Previous studies have shown that inhibition of the mammalian target of rapamycin (mTOR) pathway with rapamycin prevents epileptogenesis after pharmacologically induced status epilepticus (SE) in rat models of temporal lobe epilepsy. Because rapamycin is also known for its immunosuppressant properties we hypothesized that one of the mechanisms by which it exerts this effect could be via suppression of brain inflammation, a process that has been suggested to play a major role in the development and progression of epilepsy.. Rats were treated with rapamycin or vehicle once daily for 7 days (6 mg/kg/day, i.p.) starting 4 h after the induction of SE, which was evoked by electrical stimulation of the angular bundle. Hereafter rapamycin was administered every other day until rats were sacrificed, 6 weeks after SE. Video-electroencephalography was used to monitor the occurrence of seizures. Neuronal death, synaptic reorganization, and microglia and astrocyte activation were assessed by immunohistologic staining. Fluorescein was administered to quantify blood-brain barrier leakage.. Rapamycin treatment did not alter SE severity and duration compared to vehicle treatment rats. Rapamycin-treated rats developed hardly (n = 9) or no (n = 3) seizures during the 6-week treatment, whereas vehicle-treated rats showed a progressive increase of seizures starting 1 week after SE (mean 8 ± 2 seizures per day during the sixth week). Cell loss and sprouting that normally occur after SE were prominent but on average significantly less in rapamycin-treated rats versus vehicle-treated rats. Nevertheless, various inflammation markers (CD11b/c and CD68) were dramatically upregulated and not significantly different between post-SE groups. Of interest, blood-brain barrier leakage was barely detected in the rapamycin-treated group, whereas it was prominent in the vehicle-treated group.. mTOR inhibition led to strong reduction of seizure development despite the presence of microglia activation, suggesting that effects of rapamycin on seizure development are not due to a control of inflammation. Whether the effects on blood-brain barrier leakage in rapamycin-treated rats are a consequence of seizure suppressing properties of the drug, or contribute to a real antiepileptogenic effect still needs to be determined.

Topics: Animals; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Blood-Brain Barrier; CD11b Antigen; Cytokines; Disease Models, Animal; Drug Administration Schedule; Electric Stimulation; Electroencephalography; Immunosuppressive Agents; Male; Microglia; Monocytes; Phosphopyruvate Hydratase; Rats; Rats, Sprague-Dawley; Seizures; Signal Transduction; Sirolimus; Statistics as Topic; Statistics, Nonparametric; Status Epilepticus; Time Factors; TOR Serine-Threonine Kinases; Vimentin

Seizure susceptibility to neurological insults, including chemical convulsants, is age-dependent and most likely reflective of overall differences in brain excitability. The molecular and cellular mechanisms underlying development-dependent seizure susceptibility remain to be fully understood. Because the mammalian target of rapamycin (mTOR) pathway regulates neurite outgrowth, synaptic plasticity and cell survival, thereby influencing brain development, we tested if exposure of the immature brain to the mTOR inhibitor rapamycin changes seizure susceptibility to neurological insults. We found that inhibition of mTOR by rapamycin in immature rats (3-4 weeks old) increases the severity of seizures induced by pilocarpine, including lengthening the total seizure duration and reducing the latency to the onset of seizures. Rapamycin also reduces the minimal dose of pentylenetetrazol (PTZ) necessary to induce clonic seizures. However, in mature rats, rapamycin does not significantly change the seizure sensitivity to pilocarpine and PTZ. Likewise, kainate sensitivity was not significantly affected by rapamycin treatment in either mature or immature rats. Additionally, rapamycin treatment down-regulates the expression of potassium-chloride cotransporter 2 (KCC2) in the thalamus and to a lesser degree in the hippocampus. Pharmacological inhibition of thalamic mTOR or KCC2 increases susceptibility to pilocarpine-induced seizure in immature rats. Thus, our study suggests a role for the mTOR pathway in age-dependent seizure susceptibility.

Topics: Animals; Anticonvulsants; Blotting, Western; Convulsants; Disease Susceptibility; Down-Regulation; Immunohistochemistry; K Cl- Cotransporters; Male; Pilocarpine; Rats; Rats, Sprague-Dawley; Seizures; Sirolimus; Symporters; TOR Serine-Threonine Kinases

The mammalian target of rapamycin (mTOR) pathway integrates signals from different nutrient sources, including amino acids and glucose. Compounds that inhibit mTOR kinase activity such as rapamycin and everolimus can suppress seizures in some chronic animal models and in patients with tuberous sclerosis. However, it is not known whether mTOR inhibitors exert acute anticonvulsant effects in addition to their longer term antiepileptogenic effects. To gain insights into how rapamycin suppresses seizures, we investigated the anticonvulsant activity of rapamycin using acute seizure tests in mice.. Following intraperitoneal injection of rapamycin, normal four-week-old male NIH Swiss mice were evaluated for susceptibility to a battery of acute seizure tests similar to those currently used to screen potential therapeutics by the US NIH Anticonvulsant Screening Program. To assess the short term effects of rapamycin, mice were seizure tested in ≤ 6 hours of a single dose of rapamycin, and for longer term effects of rapamycin, mice were tested after 3 or more daily doses of rapamycin.. The only seizure test where short-term rapamycin treatment protected mice was against tonic hindlimb extension in the MES threshold test, though this protection waned with longer rapamycin treatment. Longer term rapamycin treatment protected against kainic acid-induced seizure activity, but only at late times after seizure onset. Rapamycin was not protective in the 6 Hz or PTZ seizure tests after short or longer rapamycin treatment times. In contrast to other metabolism-based therapies that protect in acute seizure tests, rapamycin has limited acute anticonvulsant effects in normal mice.. The efficacy of rapamycin as an acute anticonvulsant agent may be limited. Furthermore, the combined pattern of acute seizure test results places rapamycin in a third category distinct from both fasting and the ketogenic diet, and which is more similar to drugs acting on sodium channels.

Topics: 3-Hydroxybutyric Acid; Acute Disease; Animals; Anticonvulsants; Blood Glucose; Blotting, Western; Cerebral Cortex; Dose-Response Relationship, Drug; Electroshock; Hippocampus; Immunosuppressive Agents; Injections, Intraperitoneal; Kainic Acid; Male; Mice; Pentylenetetrazole; Phosphorylation; Ribosomal Protein S6; Seizures; Sirolimus; Time Factors; TOR Serine-Threonine Kinases

  Rapamycin (RAP) has certain antiepileptogenic features. However, it is unclear whether these effects can be explained by the anticonvulsant action of RAP, which has not been studied. To address this question, we tested potential anticonvulsant effects of RAP in immature and adult rats using different seizure models and treatment paradigms. In addition, we studied changes in the expression of neuropeptide Y (NPY) induced by RAP, which may serve as an indirect target of the RAP action..   A complex approach was adopted to evaluate the anticonvulsant potential of RAP: We used flurothyl-, pentylenetetrazole (PTZ)-, N-methyl-D-aspartate (NMDA)-, and kainic acid (KA)-induced seizures to test the effects of RAP using different pretreatment protocols in immature and adult rats. We also evaluated expression of NPY within the primary motor cortex, hippocampal CA1, and dentate gyrus (DG) after different pretreatments with RAP in immature rats..   We found the following: (1) RAP administered with short-term pretreatment paradigms has a weak anticonvulsant potential in the seizure models with compromised inhibition. (2) Lack of RAP efficacy correlates with decreased NPY expression in the cortex, CA1, and DG. Specifically in immature rats, a single dose of RAP (3 mg/kg) 4 or 24 h before seizure testing had anticonvulsant effects against PTZ-induced seizures. In the flurothyl seizure model only the 4-h pretreatment with RAP was anticonvulsant in the both age groups. Short-term pretreatments with RAP had no effects against NMDA- and KA-induced seizures tested in immature rats. Long-term pretreatments with RAP over 8 days did not show beneficial effect in all tested seizure models in developing rats. Moreover, the long-term pretreatment with RAP had a slight proconvulsant effect on KA-induced seizures. In immature rats, any lack of anticonvulsant effect (including proconvulsant effect of multiple doses of RAP) was associated with downregulation of NPY expression in the cortex and DG. In immature animals, after a single dose of RAP with 24 h delay, we found a decrease of NPY expression in DG, and CA1 as well..   Our data show weak age-, treatment paradigm-, and model-specific anticonvulsant effects of RAP as well as loss of those effects after long-term RAP pretreatment associated with downregulation of NPY expression. These findings suggest that RAP is a poor anticonvulsant and may have beneficial effects only against epileptogenesis. In addition, our data present new insights into mechanisms of RAP action on seizures indicating a possible connection between mammalian target of rapamycin (mTOR) signaling and NPY system.

Topics: Age Factors; Animals; Animals, Newborn; Anticonvulsants; Disease Models, Animal; Gene Expression Regulation; Male; Neuropeptide Y; Rats; Rats, Sprague-Dawley; Seizures; Sirolimus; Treatment Outcome

  Accumulating data have demonstrated that seizures induced by kainate (KA) or pilocarpine activate the mammalian target of rapamycin (mTOR) pathway and that mTOR inhibitor rapamycin can inhibit mTOR activation, which subsequently has potential antiepileptic effects. However, a preliminary study showed a paradoxical exacerbation of increased mTOR pathway activity reflected by S6 phosphorylation when rapamycin was administrated within a short period before KA injection. In the present study, we examined this paradoxical effect of rapamycin in more detail, both in normal rats and KA-injected animals..   Normal rats or KA-treated rats pretreated with rapamycin at different time intervals were sacrificed at various time points (1, 3, 6, 10, 15, and 24 h) after rapamycin administration or seizure onset for western blotting analysis. Phosphorylation of mTOR signaling target of Akt, mTOR, Rictor, Raptor, S6K, and S6 were analyzed. Seizure activity was monitored behaviorally and graded according to a modified Racine scale (n = 6 for each time point). Neuronal cell death was detected by Fluoro-Jade B staining..   In normal rats, we found that rapamycin showed the expected dose-dependent inhibition of S6 phosphorylation 3-24 h after injection, whereas a paradoxical elevation of S6 phosphorylation was observed 1 h after rapamycin. Similarly, pretreatment with rapamycin over 10 h before KA inhibited the KA seizure-induced mTOR activation. In contrast, rapamycin administered 1-6 h before KA caused a paradoxical increase in the KA seizure-induced mTOR activation. Rats pretreated with rapamycin 1 h prior to KA exhibited an increase in severity and duration of seizures and more neuronal cell death as compared to vehicle-treated groups. In contrast, rapamycin pretreated 10 h prior to KA had no effect on the seizures and decreased neuronal cell death. The paradoxical effect of rapamycin on S6 phosphorylation was correlated with upstream mTOR signaling and was reversed by pretreatment of perifosine, an Akt inhibitor..   These data indicate the complexity of S6 regulation and its effect on epilepsy. Paradoxical effects of rapamycin need to be considered in clinical applications, such as for potential treatment for epilepsy and other neurologic disorders.

Topics: Animals; Male; Phosphorylation; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases; Seizures; Sirolimus; TOR Serine-Threonine Kinases; Treatment Outcome

Temporal lobe epilepsy is prevalent and can be difficult to treat effectively. Granule cell axon (mossy fiber) sprouting is a common neuropathological finding in patients with mesial temporal lobe epilepsy, but its role in epileptogenesis is unclear and controversial. Focally infused or systemic rapamycin inhibits the mammalian target of rapamycin (mTOR) signaling pathway and suppresses mossy fiber sprouting in rats. We tested whether long-term systemic treatment with rapamycin, beginning 1 d after pilocarpine-induced status epilepticus in mice, would suppress mossy fiber sprouting and affect the development of spontaneous seizures. Mice that had experienced status epilepticus and were treated for 2 months with rapamycin displayed significantly less mossy fiber sprouting (42% of vehicle-treated animals), and the effect was dose dependent. However, behavioral and video/EEG monitoring revealed that rapamycin- and vehicle-treated mice displayed spontaneous seizures at similar frequencies. These findings suggest mossy fiber sprouting is neither pro- nor anti-convulsant; however, there are caveats. Rapamycin treatment also reduced epilepsy-related hypertrophy of the dentate gyrus but did not significantly affect granule cell proliferation, hilar neuron loss, or generation of ectopic granule cells. These findings are consistent with the hypotheses that hilar neuron loss and ectopic granule cells might contribute to temporal lobe epileptogenesis.

Topics: Analysis of Variance; Animals; Anticonvulsants; Cation Transport Proteins; Diazepam; Disease Models, Animal; Drug Administration Schedule; Electroencephalography; Epilepsy, Temporal Lobe; Hippocampus; Immunosuppressive Agents; Mice; Mossy Fibers, Hippocampal; Neurons; Seizures; Sirolimus; Videotape Recording

Inhibition of mTOR by rapamycin has been shown to suppress seizures in TSC/PTEN genetic models. Rapamycin, when applied immediately before or after a neurological insult, also prevents the development of spontaneous recurrent seizures (epileptogenesis) in an acquired model. In the present study, we examined the mTOR pathway in rats that had already developed chronic spontaneous seizures in a pilocarpine model. We found that mTOR is aberrantly activated in brain tissues from rats with chronic seizures. Furthermore, inhibition of mTOR by rapamycin treatment significantly reduces seizure activity. Finally, mTOR inhibition also significantly suppresses mossy fiber sprouting. Our findings suggest the possibility for a much broader window for intervention for some acquired epilepsies by targeting the mTOR pathway.

Topics: Animals; Convulsants; Disease Models, Animal; Epilepsy; Hippocampus; Male; Mossy Fibers, Hippocampal; Neuronal Plasticity; Pilocarpine; Rats; Rats, Sprague-Dawley; Seizures; Signal Transduction; Sirolimus; TOR Serine-Threonine Kinases

The authors present a 10-year-old girl with tuberous sclerosis complex who has been receiving rapamycin for 10 months for seizure control. She was started at 0.05 mg/kg/d and titrated to an effective dose of 0.15 mg/kg/d. There was a dramatic reduction in seizure frequency with rapamycin therapy. Further studies are needed to objectively investigate the benefits of rapamycin in tuberous sclerosis complex and to clarify its mechanism of seizure control.

Topics: Anticonvulsants; Carbamazepine; Cerebral Cortex; Child; Dose-Response Relationship, Drug; Drug Therapy, Combination; Female; Fructose; Humans; Immunosuppressive Agents; Magnetic Resonance Imaging; Neurosurgical Procedures; Paresis; Seizures; Sirolimus; Topiramate; Treatment Outcome; Tuberous Sclerosis; Virus Diseases

Understanding molecular mechanisms mediating epileptogenesis is critical for developing more effective therapies for epilepsy. We recently found that the mammalian target of rapamycin (mTOR) signaling pathway is involved in epileptogenesis, and mTOR inhibitors prevent epilepsy in a mouse model of tuberous sclerosis complex. Here, we investigated the potential role of mTOR in a rat model of temporal lobe epilepsy initiated by status epilepticus. Acute kainate-induced seizures resulted in biphasic activation of the mTOR pathway, as evident by an increase in phospho-S6 (P-S6) expression. An initial rise in P-S6 expression started approximately 1 h after seizure onset, peaked at 3-6 h, and returned to baseline by 24 h in both hippocampus and neocortex, reflecting widespread stimulation of mTOR signaling by acute seizure activity. After resolution of status epilepticus, a second increase in P-S6 was observed in hippocampus only, which started at 3 d, peaked 5-10 d, and persisted for several weeks after kainate injection, correlating with the development of chronic epileptogenesis within hippocampus. The mTOR inhibitor rapamycin, administered before kainate, blocked both the acute and chronic phases of seizure-induced mTOR activation and decreased kainate-induced neuronal cell death, neurogenesis, mossy fiber sprouting, and the development of spontaneous epilepsy. Late rapamycin treatment, after termination of status epilepticus, blocked the chronic phase of mTOR activation and reduced mossy fiber sprouting and epilepsy but not neurogenesis or neuronal death. These findings indicate that mTOR signaling mediates mechanisms of epileptogenesis in the kainate rat model and that mTOR inhibitors have potential antiepileptogenic effects in this model.

Topics: Analysis of Variance; Animals; Bromodeoxyuridine; Cell Death; Disease Models, Animal; Electroencephalography; Epilepsy, Temporal Lobe; Fluoresceins; Gene Expression Regulation; Immunosuppressive Agents; In Situ Nick-End Labeling; Kainic Acid; Male; Mossy Fibers, Hippocampal; Organic Chemicals; Protein Kinases; Rats; Rats, Sprague-Dawley; Seizures; Signal Transduction; Sirolimus; Time Factors; TOR Serine-Threonine Kinases; Video Recording

Neurological complications are common in transplant recipients treated with immunosuppressant calcineurin inhibitors. Rapamycin, a macrolide antibiotic, was suggested as an alternative agent in patients who develop calcineurin inhibitor associated neurotoxicity, including seizure attacks. The aim of the present study was to test the effect of rapamycin on the bioelectrical activity and evoked field excitatory postsynaptic potentials (fEPSP) in CA1 area of hippocampal tissues and compare its effect with FK506, a calcineurin inhibitor agent. Application of rapamycin at different concentrations neither affected the bioelectrical activity nor changed fEPSP magnitude. In contrast, FK506 elicited epileptiform burst discharges and significantly enhanced fEPSP magnitude. This study supports the suggestion that rapamycin could be used as an alternative to calcineurin inhibitors in the event of neurotoxicity.

Topics: Animals; Brain; Calcineurin; Calcineurin Inhibitors; Dose-Response Relationship, Drug; Epilepsy; Evoked Potentials; Excitatory Postsynaptic Potentials; Graft Rejection; Hippocampus; Immunosuppressive Agents; In Vitro Techniques; Neurons; Neurotoxicity Syndromes; Rats; Seizures; Sirolimus; Tacrolimus; Transplantation

We assayed the effects of rapamycin, an immunomodulatory agent known to inhibit the activity of the mammalian target of rapamycin (mTOR) cascade, on candidate gene expression and single unit firing properties in cultured rat hippocampal neurons as a strategy to define the effects of rapamycin on neuronal gene transcription and excitability.. Rapamycin was added (100nM) to cultured hippocampal neurons on days 3 and 14. Neuronal somatic size and dendritic length were assayed by immunohistochemistry and digital imaging. Radiolabeled mRNA was amplified from single hippocampal pyramidal neurons and used to probe cDNA arrays containing over 100 distinct candidate genes including cytoskeletal element, growth factor, transcription factor, neurotransmitter, and ion channel genes. In addition, the effects of rapamycin (200nM) on spontaneous neuronal activity and voltage-dependent currents were assessed.. There were no effects of rapamycin on cell size or dendrite length. Rapamycin altered expression of distinct mRNAs in each gene family on days 3 and 14 in culture. Single unit recordings from neurons exposed to rapamycin exhibited no change from baseline. When spontaneous activity was increased by blocking GABA-mediated inhibition with bicuculline, a fraction of the neurons exhibited a decreased duration of spontaneous bursts and a decrease in synaptic inputs. Rapamycin did not appear to alter voltage-dependent Na(+) or K(+) currents underlying action potentials.. These data demonstrate that rapamycin does not produce neurotoxicity nor alter dendritic growth and complexity in vitro and does not significantly alter voltage-gated sodium and potassium currents. Rapamycin does affect neuronal gene transcription in vitro. Use of rapamycin in clinical trials for patients with tuberous sclerosis complex warrants vigilance for possible effects on seizure frequency and neurocognitive function.

Topics: Animals; Cell Count; Cell Size; Cells, Cultured; Dendrites; DNA, Complementary; Electrophysiology; Gene Expression; Hippocampus; Immunohistochemistry; Immunosuppressive Agents; Nerve Net; Neurons; Patch-Clamp Techniques; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Seizures; Sirolimus

Anemia is common in patients with chronic kidney disease (CKD) and those who have received a kidney allograft. Anemia is most prevalent in kidney transplant recipients before and immediately after transplantation, but also can occur months after transplantation if the donor kidney begins to fail. Replacement therapy for CKD-related and posttransplantation anemia is effective through the administration of exogenous erythropoiesis-stimulating proteins. Darbepoetin alfa (Aranesp; Amgen Inc, Thousand Oaks, CA) is a unique erythropoiesis-stimulating protein that can be administered at an extended dosing interval relative to recombinant human erythropoietin because of its approximately 3-fold longer serum half-life. Although darbepoetin alfa has been shown to be an effective treatment for patients with anemia of CKD and anemia after kidney transplantation, limited data have been published showing efficacy in treating women with anemia of these conditions during pregnancy. We report a case of successful darbepoetin alfa treatment for severe anemia in a pregnant transplant recipient.

Topics: Adult; Anemia; Cesarean Section; Contraindications; Cyclosporine; Darbepoetin alfa; Erythropoietin; Female; Ferrous Compounds; Humans; Hydronephrosis; Immunosuppressive Agents; Kidney Transplantation; Nephrostomy, Percutaneous; Postoperative Complications; Pre-Eclampsia; Pregnancy; Pregnancy Complications, Hematologic; Pregnancy, High-Risk; Puerperal Disorders; Seizures; Sirolimus; Stents; Treatment Refusal

Topics: Astrocytoma; Brain Neoplasms; Carmustine; Dexamethasone; Diagnosis, Differential; Frontal Lobe; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Phenytoin; Piloerection; Seizures; Sirolimus; Taste Disorders; Temporal Lobe

We describe the case of a paediatric kidney transplant patient who developed cyclosporin neurotoxicity on day 7 post-transplant. Consequently, her cyclosporin was stopped and she was commenced on rapamycin. Over the next 3 weeks her creatinine remained elevated and she had several episodes of biopsy proven rejection, despite increasing the initial dose of rapamycin by tenfold. Her whole blood rapamycin levels also remained well below the target range of 10-20 ng/ml. On day 38 post-transplant, the decision was made to add tacrolimus to her immunosuppression. At the same time, phenytoin, which had been commenced during her episode of cyclosporin neurotoxicity, was withdrawn. After this point her rapamycin blood levels rapidly increased to within the therapeutic range and she improved clinically. We propose that phenytoin, as a p450 cytochrome enzyme inducer, increased the metabolism of rapamycin in this patient and hence decreased the initial therapeutic effectiveness of this drug.

Topics: Anticonvulsants; Child; Cyclosporine; Cytochrome P-450 Enzyme System; Enzyme Induction; Female; Graft Rejection; Humans; Immunosuppressive Agents; Kidney Failure, Chronic; Phenytoin; Seizures; Sirolimus