Probing the lithium-response pathway in hiPSCs implicates the phosphoregulatory set-point for a cytoskeletal modulator in bipolar pathogenesis.

The molecular pathogenesis of bipolar disorder (BPD) is poorly understood. Using human-induced pluripotent stem cells (hiPSCs) to unravel such mechanisms in polygenic diseases is generally challenging. However, hiPSCs from BPD patients responsive to lithium offered unique opportunities to discern lithium's target and hence gain molecular insight into BPD. By profiling the proteomics of BDP-hiPSC-derived neurons, we found that lithium alters the phosphorylation state of collapsin response mediator protein-2 (CRMP2). Active nonphosphorylated CRMP2, which binds cytoskeleton, is present throughout the neuron; inactive phosphorylated CRMP2, which dissociates from cytoskeleton, exits dendritic spines. CRMP2 elimination yields aberrant dendritogenesis with diminished spine density and lost lithium responsiveness (LiR). The "set-point" for the ratio of pCRMP2:CRMP2 is elevated uniquely in hiPSC-derived neurons from LiR BPD patients, but not with other psychiatric (including lithium-nonresponsive BPD) and neurological disorders. Lithium (and other pathway modulators) lowers pCRMP2, increasing spine area and density. Human BPD brains show similarly elevated ratios and diminished spine densities; lithium therapy normalizes the ratios and spines. Consistent with such "spine-opathies," human LiR BPD neurons with abnormal ratios evince abnormally steep slopes for calcium flux; lithium normalizes both. Behaviorally, transgenic mice that reproduce lithium's postulated site-of-action in dephosphorylating CRMP2 emulate LiR in BPD. These data suggest that the "lithium response pathway" in BPD governs CRMP2's phosphorylation, which regulates cytoskeletal organization, particularly in spines, modulating neural networks. Aberrations in the posttranslational regulation of this developmentally critical molecule may underlie LiR BPD pathogenesis. Instructively, examining the proteomic profile in hiPSCs of a functional agent-even one whose mechanism-of-action is unknown-might reveal otherwise inscrutable intracellular pathogenic pathways.

Pharmacokinetic-pharmacodynamic assessment of topiramate dosing regimens for children with epilepsy 2 to <10 years of age.

PURPOSE: To identify and validate the efficacious monotherapy dosing regimen for topiramate in children aged 2 to <10 years with newly diagnosed epilepsy using pharmacokinetic-pharmacodynamic (PK-PD) modeling and simulation bridging. METHODS: Several models were developed in pediatric and adult populations to relate steady-state trough plasma concentrations (C(min)) of topiramate to the magnitude of clinical effect in monotherapy and adjunctive settings. These models were integrated to derive and support the monotherapy dosing regimen for pediatric patients. KEY FINDINGS: A two-compartmental population PK model with first-order absorption described the time course of topiramate C(min) as a function of dosing regimen. Disposition of topiramate was related to age, body weight, and use of various concomitant antiepileptic drugs. The PK-PD model for monotherapy indicated that the hazard of time to first seizure decreased with increasing C(min) and time since randomization. Higher baseline seizure frequency increased risk for seizures. Age did not significantly influence hazard of time to first seizure after randomization to monotherapy. For adjunctive therapy, the distribution of drug and placebo responses was not significantly different among age groups. Based on the available PK-PD modeling data, the dosing regimen expected to achieve a 65-75% seizure freedom rate after 1 year for pediatric patients age 2-10 years is approximately 6-9 mg/kg per day. SIGNIFICANCE: This analysis indicated no difference in PK-PD of topiramate between adult and pediatric patients. Effects of indication and body weight on PK were adequately integrated into the model, and monotherapy dosing regimens were identified for children 2-10 years of age.

aph-1 and pen-2 are required for Notch pathway signaling, gamma-secretase cleavage of betaAPP, and presenilin protein accumulation.

Presenilins are components of the gamma-secretase protein complex that mediates intramembranous cleavage of betaAPP and Notch proteins. A C. elegans genetic screen revealed two genes, aph-1 and pen-2, encoding multipass transmembrane proteins, that interact strongly with sel-12/presenilin and aph-2/nicastrin. Human aph-1 and pen-2 partially rescue the C. elegans mutant phenotypes, demonstrating conserved functions. The human genes must be provided together to rescue the mutant phenotypes, and the inclusion of presenilin-1 improves rescue, suggesting that they interact closely with each other and with presenilin. RNAi-mediated inactivation of aph-1, pen-2, or nicastrin in cultured Drosophila cells reduces gamma-secretase cleavage of betaAPP and Notch substrates and reduces the levels of processed presenilin. aph-1 and pen-2, like nicastrin, are required for the activity and accumulation of gamma-secretase.

Glycogen synthase kinase-3beta modulates notch signaling and stability.

Notch receptors modulate transcriptional targets following the proteolytic release of the Notch intracellular domain (NotchIC). Phosphorylated forms of NotchIC have been identified within the nucleus and have been associated with CSL members, as well as correlated with regions of the receptor that are required for activity. Genetic studies have suggested that the Drosophila homolog of glycogen synthase kinase-3beta (GSK3beta), Shaggy, may act as a positive modulator of the Notch signaling. GSK3beta is a serine/threonine kinase and is a component of the Wnt/wingless signaling cascade. Here, we observed that GSK3beta was able to bind and phosphorylate Notch1IC in vitro, and attenuation of GSK3beta activity reduced phosphorylation of NotchIC in vivo. Functionally, ligand-activated signaling through the endogenous Notch1 receptor was reduced in GSK3beta null fibroblasts, implying a positive role for GSK3beta in mammalian Notch signaling. As a possible mechanistic explanation of the effect of GSK3beta on Notch signaling, we observed that inhibition of GSK3beta shortened the half-life of Notch1IC. Conversely, activated GSK3beta reduced the quantity of Notch1IC that was degraded by the proteasome. These studies reveal that GSK3beta modulates Notch1 signaling, possibly through direct phosphorylation of the intracellular domain of Notch, and that the activity of GSK3beta protects the intracellular domain from proteasome degradation.

Effect of concomitant use of memantine on mortality and efficacy outcomes of galantamine-treated patients with Alzheimer's disease: post-hoc analysis of a randomized placebo-controlled study.

BACKGROUND: A large, prospective, 2-year, randomized study in patients with mild-to-moderate Alzheimer's disease or mixed dementia demonstrated reductions in mortality and cognitive/functional decline in galantamine-treated patients. A post-hoc analysis was conducted to study the effect of (the presence or absence of) concomitant memantine use on treatment outcome. METHODS: Randomized patients (N = 2045) were divided into subgroups based on memantine use. Analyses included demographic and clinical characteristics (age, nursing home placement, Mini-Mental State Examination (MMSE) and Disability Assessment for Dementia (DAD) scores) and mortality endpoints. RESULTS: Overall, 496 (24.3 %) patients were memantine users and were older (mean (SD), 74.0 (8.76) vs 72.8 (8.76), p = 0.008), with lower MMSE scores (18.2 (4.16) vs 19.2 (4.02), p < 0.0001) and DAD scores (58.0 (23.49) vs 62.5 (20.52), p < 0.0001) than nonusers. Mortality rates (per 100 patient-years) in memantine nonusers (n = 1549) were lower for galantamine (1.39) vs placebo-treated patients (4.15). In memantine users, mortality rates were similar for placebo-treated (4.49) and galantamine-treated patients (5.57). In memantine nonusers at 24 months, the decline in MMSE scores (effect size (95 % CI) 0.25 (0.14; 0.36)) and DAD scores (0.17 (0.06; 0.28)) from baseline was lower in galantamine patients vs placebo patients. The absence of these benefits in memantine users could not be explained by baseline age, MMSE, or DAD scores. CONCLUSION: This post-hoc analysis shows that the beneficial effects of galantamine at 2 years post treatment were not observed in patients who had been placed on background memantine. The reasons for memantine treatment and the possibility of interaction between memantine and galantamine merit further investigation. TRIAL REGISTRATION: ClinicalTrials.gov NCT00679627 . Registered 15 May 2008.

Steady-state pharmacokinetics of galantamine are not affected by addition of memantine in healthy subjects.

To evaluate the effect of multiple doses of memantine on the pharmacokinetics of galantamine and to assess the safety and tolerability of galantamine with adjunctive memantine treatment, an open-label, single-center, drug interaction study was conducted in 16 healthy adults. Subjects received an 8-mg dose of galantamine extended release once daily during week 1 and a 16-mg dose of galantamine extended release once daily during week 2. During weeks 3 and 4, they received a 16-mg dose of galantamine extended release once daily and a 10-mg dose of memantine twice daily, except on days 1 and 2 of week 3, when memantine was given as 10 mg once daily. The pharmacokinetic profile and parameters of galantamine at steady state were similar after administration of a 16-mg dose of galantamine once daily alone and after administration with a 10-mg dose of memantine twice daily. Galantamine 16 mg once daily with adjunctive memantine 10 mg twice daily was well tolerated and safe in healthy subjects.

Possible association of NTDs with a polyhistidine tract polymorphism in the ZIC2 gene.

Neural tube defects (NTDs) and brain malformations represent a common finding in chromosome 13q deletion patients. Hemizygosity for ZIC2, which is located in the 13q32 critical deletion region, results in holoprosencephaly (HPE) in humans, and diminished expression of ZIC2 results in HPE as well as lumbosacral NTDs in mice. Taken together, these observations led us to hypothesize that ZIC2 mutations may be a cause of isolated NTD. To test this, we screened 192 NTD patients for mutations in ZIC2. While we did not find ZIC2 mutations in these patients, we did find some evidence of a possible association between a histidine tract polymorphism in ZIC2 and NTDs. Our sample was too small to reach definitive conclusions, but the evidence is sufficiently intriguing to encourage further research. If this association is confirmed, subtle alterations in ZIC2 activity may confer a risk of NTD.

The effect of galantamine on brain atrophy rate in subjects with mild cognitive impairment is modified by apolipoprotein E genotype: post-hoc analysis of data from a randomized controlled trial.

INTRODUCTION: The aim of this investigation was to assess the effect of galantamine, an acetylcholinesterase inhibitor and allosteric modulator of nicotinic receptors, on brain atrophy in individuals with mild cognitive impairment (MCI), and to assess effect modification by apolipoprotein E (APOE) genotype. METHODS: We used data from the Galantamine-International-11 (Gal-Int-11) trial, a 24-month, randomized, double blind, placebo-controlled, flexible-dose (16 to 24 mg daily) study in patients with MCI. Brain magnetic resonance imaging (MRI), including a 3-dimensional T1-weighted gradient echo volumetric sequence, was performed at screening and at 24 months. We recorded whole brain and hippocampal volumes, and calculated annual atrophy rates. Linear regression analysis was used to calculate adjusted mean differences in the rate of whole brain and hippocampal atrophy, between MCI patients treated with galantamine and with placebo. Additionally, we performed stratified analyses according to APOE genotype. RESULTS: Data from 364 MCI patients with 24-month MRI data (galantamine, n = 176; placebo, n = 188) were included in the volumetric analysis. Subjects treated with galantamine demonstrated a lower rate of whole brain atrophy compared to those treated with placebo (adjusted mean difference 0.18% per year (95% confidence interval (CI) 0.04; 0.30)). Stratified analyses according to APOE genotype, showed that this effect was confined to patients who carried an APOE ϵ4 allele (adjusted mean difference 0.28% per year (95% CI 0.07; 0.50)). Rates of hippocampal atrophy did not differ significantly between study groups. CONCLUSIONS: Patients with MCI who were treated with galantamine demonstrated a lower rate of whole brain atrophy, but not of hippocampal atrophy, over a 24-month treatment period, compared to those treated with placebo. This protective effect of galantamine on whole brain atrophy rate in MCI was only present in APOE ϵ4 carriers.

Evaluation of JNJ-26489112 in patients with photosensitive epilepsy: a placebo-controlled, exploratory study.

PURPOSE: To evaluate the activity of JNJ-26489112 in patients with photosensitive epilepsy and determine the doses that result in reduction or complete suppression of the intermittent photic stimulation (IPS) induced photoparoxysmal-EEG response (PPR). METHODS: In this multicenter, single-blind, within subject, placebo-controlled, sequential dose, exploratory study, 12 adult patients (3 men; 9 women) with idiopathic photosensitive epilepsy, with and without concomitant antiepileptic drug (AED) therapy, underwent standardized IPS under three eye conditions (open, during closure, and closed) for up to 12h after receiving a single oral dose of placebo on day 1, JNJ-26489112 on day 2, and a second dose of placebo on day 3. Based on review of the blinded EEG data, the standardized photosensitive range (SPR) (i.e., upper and lower frequencies of the IPS-induced PPR), was calculated for each eye condition at each time point. A positive response was defined as a reduction of the SPR in ≥3 out of 4 consecutive time points in ≥1 eye condition on either day 2 or 3 compared with baseline (day 1) while complete suppression was defined as disappearance of an IPS-induced PPR (i.e., SPR=0). For the first four patients (Cohort 1), JNJ-26489112 dose was 1000 mg, and the dose was escalated to a maximum of 3000 mg in subsequent cohorts. Blood and plasma samples were collected for pharmacokinetic evaluations along with measurements of concurrent AED concentrations. Safety was also assessed. RESULTS: The majority of patients showed a positive response on day 2 following JNJ-26489112 administration: 3/4 patients (1000 mg dose), 3/4 patients (2000 mg dose), and 2/3 patients (3000 mg). There was an apparent dose-dependent effect observed in patients who exhibited complete suppression of the SPR: 0/4 patients (1000 mg dose), 1/4 patient (2000 mg dose), and 2/3 patients (3000 mg dose). The median tmax of JNJ-26489112 (range: 3.73-5.04 h) in plasma was similar across all 3 dose groups and plasma exposure of JNJ-26489112 increased proportionally with dose; approximate mean Cmax of 16, 28, and 42 µg/mL for the 1000-, 2000-, and 3000 mg cohorts, respectively. Concentrations of other AEDs did not appear to be affected by co-administration of JNJ-26489112. JNJ-26489112 was generally well-tolerated with the most frequent adverse events (>10%) reported being mild headache, dizziness, and nausea. CONCLUSION: Single oral doses of JNJ-26489112 were well-tolerated and the pharmacodynamic effects appeared to be dose-related in patients with idiopathic, photosensitive epilepsy.

Effects of galantamine in a 2-year, randomized, placebo-controlled study in Alzheimer's disease.

BACKGROUND: Currently available treatments for Alzheimer's disease (AD) can produce mild improvements in cognitive function, behavior, and activities of daily living in patients, but their influence on long-term survival is not well established. This study was designed to assess patient survival and drug efficacy following a 2-year galantamine treatment in patients with mild to moderately severe AD. METHODS: In this multicenter, double-blind study, patients were randomized 1:1 to receive galantamine or placebo. One primary end point was safety; mortality was assessed. An independent Data Safety Monitoring Board monitored mortality for the total deaths reaching prespecified numbers, using a time-to-event method and a Cox-regression model. The primary efficacy end point was cognitive change from baseline to month 24, as measured by the Mini-Mental State Examination (MMSE) score, analyzed using intent-to-treat analysis with the 'last observation carried forward' approach, in an analysis of covariance model. RESULTS: In all, 1,024 galantamine- and 1,021 placebo-treated patients received study drug, with mean age ~73 years, and mean (standard deviation [SD]) baseline MMSE score of 19 (4.08). A total of 32% of patients (661/2,045) completed the study, 27% (554/2,045) withdrew, and 41% (830/2,045) did not complete the study and were discontinued due to a Data Safety Monitoring Board-recommended early study termination. The mortality rate was significantly lower in the galantamine group versus placebo (hazard ratio [HR] =0.58; 95% confidence interval [CI]: 0.37; 0.89) (P=0.011). Cognitive impairment, based on the mean (SD) change in MMSE scores from baseline to month 24, significantly worsened in the placebo (-2.14 [4.34]) compared with the galantamine group (-1.41 [4.05]) (P<0.001). Functional impairment, based on mean (SD) change in the Disability Assessment in Dementia score (secondary end point), at month 24 significantly worsened in the placebo (-10.81 [18.27]) versus the galantamine group (-8.16 [17.25]) (P=0.002). Incidences of treatment-emergent adverse events were 54.0% for the galantamine and 48.6% for the placebo group. CONCLUSION: Long-term treatment with galantamine significantly reduced mortality and the decline in cognition and daily living activities, in mild to moderate AD patients. IDENTIFICATION: This study is registered at ClinicalTrials.gov (NCT00679627).

Alzheimer's disease research and development: a call for a new research roadmap.

Epidemiological projections of the prevalence of Alzheimer's disease (AD) and related dementias, the rapidly expanding population over the age of 65, and the enormous societal consequence on health, economics, and community foretell of a looming global public health crisis. Currently available treatments for AD are symptomatic, with modest effect sizes and limited impact on longer term disease outcomes. There have been no newly approved pharmaceutical treatments in the last decade, despite enormous efforts to develop disease-modifying treatments directed at Alzheimer's-associated pathology. An unprecedented collaborative effort of government, regulators, industry, academia, and the community at-large is needed to address this crisis and to develop an actionable plan for rapid progress toward successfully developing effective treatments. Here, we map out a course of action in four key priority areas, including (1) addressing the fundamental mechanisms of disease, with the goal of developing a core set of research tools, a framework for data sharing, and creation of accessible validated and replicated disease models; (2) developing translational research that emphasizes rapid progress in disease model development and better translation from preclinical to clinical stages, deploying leading technologies to more accurately develop predictive models; (3) preventing AD through the development of robust methods and resources to advance trials and creating fundamental resources such as continuous adaptive trials, registries, data repositories, and instrument development; and (4) innovating public/private partnerships and global collaborations, with mechanisms to incentivize collaborations and investments, develop larger precompetitive spaces, and more rapid data sharing.

Implications and limitations of cellular reprogramming for psychiatric drug development.

Human-induced pluripotent stem cells (hiPSCs) derived from somatic cells of patients have opened possibilities for in vitro modeling of the physiology of neural (and other) cells in psychiatric disease states. Issues in early stages of technology development include (1) establishing a library of cells from adequately phenotyped patients, (2) streamlining laborious, costly hiPSC derivation and characterization, (3) assessing whether mutations or other alterations introduced by reprogramming confound interpretation, (4) developing efficient differentiation strategies to relevant cell types, (5) identifying discernible cellular phenotypes meaningful for cyclic, stress induced or relapsing-remitting diseases, (6) converting phenotypes to screening assays suitable for genome-wide mechanistic studies or large collection compound testing and (7) controlling for variability in relation to disease specificity amidst low sample numbers. Coordination of material for reprogramming from patients well-characterized clinically, genetically and with neuroimaging are beginning, and initial studies have begun to identify cellular phenotypes. Finally, several psychiatric drugs have been found to alter reprogramming efficiency in vitro, suggesting further complexity in applying hiPSCs to psychiatric diseases or that some drugs influence neural differentiation moreso than generally recognized. Despite these challenges, studies utilizing hiPSCs may eventually serve to fill essential niches in the translational pipeline for the discovery of new therapeutics.

Adaptive behavior outcomes in infants treated with adjunctive topiramate.

Data from two global studies (6-week open-label, phase 1 study; 20-day double-blind, phase 3 study) and their 1-year open-label extensions were pooled to assess long-term effects of adjunctive topiramate on adaptive behavior in infants with clinical or video-electroencephalographic evidence of refractory, partial-onset seizures. The primary safety and efficacy results of adjunctive topiramate treatment were reported previously. We report the changes in adaptive behavior of infants, based on Vineland Scales of Adaptive Behavior. Of 284 infants (mean [S.D.] age, 12 [6.3] months) enrolled, 89% (n = 252) manifested partial-onset seizures, and 41% (n = 116) manifested clinically relevant, symptomatic etiologies at pretreatment baseline. Overall, Vineland scores were below average at pretreatment baseline. The most frequently used concomitant antiepileptic drugs included valproic acid (59%), phenobarbital (31%), and carbamazepine (19%). The most common treatment-emergent cognitive and neuropsychiatric adverse events included anorexia (35%) and somnolence (27%). A clinically significant decline (approximately 15 points, or 1 S.D.) occurred in both Vineland Scales composite (mean change, -14.0) and domain standard scores from pretreatment baseline to open-label extension endpoint. However, individual domain raw scores increased, indicating that infants progressed in acquisitions of adaptive skill, but at a slower rate than the normative population.

Modeling complex neuropsychiatric disorders with human induced pluripotent stem cells.

Identifying the molecular and cellular basis of complex neuropsychiatric disorders (cNPDs) has been limited by the inaccessibility of central neurons, variability within broad diagnostic classifications, and the interplay of genetic and environmental factors. Recent work utilizing neuronally differentiated human induced pluripotent stem cells (hiPSCs) from Mendelian and polygenic cNPDs is beginning to illuminate neuritic, synaptic or cell body variations accompanied by specific gene or protein expression alterations largely mimicking known pathology. In some cases, phenotypes have only emerged after application of cellular stress or long duration of differentiation. Pathological and cellular expression features are fully or partially responsive to pharmacological treatment highlighting the potential utility of differentiated hiPSCs for discovery of personalized therapeutics and for identifying pathogenetically relevant targets in subgroups of patients within a broad syndromic classification. Because of the inherent variability in developing and differentiating hiPSC lines and the multiple comparisons implicit in 'omics' technologies, rigorous algorithms for assuring statistical significance and independent confirmation of results, will be required for robust modeling of cNPDs.

Long-term open-label study of adjunctive topiramate in infants with refractory partial-onset seizures.

Data from 2 studies (phase 1 and phase 3) in infants <2 years old (N = 284; mean [SD] age, 12[6.3] months) with refractory partial-onset seizures were pooled to assess the long-term safety up to 1 year (primary objective) and tolerability of adjunctive topiramate treatment (mean treatment duration = 282 days). Monthly seizure rate summaries were also assessed. During the open-label extensions of these studies, study medication was first titrated to a dose of 25 mg/kg/d with subsequent uptitration to the maximum dosage tolerated, or seizure freedom, or a maximum of 60 mg/kg/d, whichever occurred first. The most common treatment-emergent adverse events (≥30%) were fever (52%), respiratory tract infections (51%), anorexia (35%), and acidosis (31%). Mean (SD) changes from pretreatment baseline to endpoint in Z scores for growth parameters were as follows: -0.82 (1.19) (body weight), -0.45 (1.60) (body length), and -0.36 (1.02) (head circumference).Tolerability in infants was consistent with previous studies.

Changes in gamma-secretase activity and specificity caused by the introduction of consensus aspartyl protease active motif in Presenilin 1.

Presenilin (PS1 or PS2) is an essential component of the active gamma-secretase complex that liberates the Abeta peptides from amyloid precursor protein (APP). PS1 is regarded as an atypical aspartyl protease harboring two essential aspartic acids in the context of the sequence D257LV and D385FI, respectively, rather than the typical DTG...DTG catalytic motif of classical aspartyl proteases. In the present studies, we introduced the sequence DTG in PS1 at and around the catalytic D257 and D385 residues to generate three PS1 mutants: D257TG, D385TG, and the double-mutant D257TG/D385TG. The effects of these changes on the gamma-secretase activity in the presence or absence of gamma-secretase inhibitors and modulators were investigated. The results showed that PS1 mutants having D385TG robustly enhanced Abeta42 production compared to the wild type (wt), and were more sensitive than wt to inhibition by a classical aspartyl protease transition state mimic, and fenchylamine, a sulfonamide derivative. Unlike wt PS1 and some of its clinical mutants, all three PS1 artificial mutants decreased cleavage of Notch S3-site, suggesting that these artificial mutations may trigger conformational changes at the substrate docking and catalytic site that cause alteration of substrate specificity and inhibition pattern. Consistent with this notion, we have found that NSAID enzymatic inhibitors of COX, known modulators of the gamma-secretase activity, cause PS1 mutants containing D385TG to produce higher levels of both Abeta38 and Abeta42, but to reduce levels of Abeta39, showing a pattern of Abeta formation different from that observed with wild type PS1 and its clinical mutants. This study provides an important structural clue for the rational design of drugs to inhibit processing of APP at the gamma-site without interfering with Notch processing.

Topiramate for migraine prevention in adolescents: a pooled analysis of efficacy and safety.

OBJECTIVE: To characterize the efficacy and safety of topiramate for migraine prevention in adolescents from 3 randomized, 26-week, double-blind, placebo-controlled trials. BACKGROUND: Limited information is available regarding the efficacy and safety of prophylactic medications for treatment of adolescent migraine, a significant health problem. In studies that included adults and children, topiramate 100 and 200 mg/day were effective and generally well-tolerated in the prevention of migraine headache. METHODS: We performed a post hoc subset analysis of the efficacy and safety data from the 51 patients, ages 12-17 years, enrolled in 3 pivotal trials of topiramate for migraine prophylaxis. RESULTS: Daily treatment with topiramate 50, 100, and 200 mg for 26 weeks reduced monthly migraine frequency from baseline 46% (P= .07), 63% (P= .02), and 65% (P= .04), respectively, compared with placebo (16%). Similarly, topiramate reduced both the monthly mean number of migraine days (1, 4, and 5 days for topiramate 50, 100, and 200 mg/day, respectively, vs 1 day for placebo) and percentage of days during which acute migraine medications were administered (59%, 54%, and 67% for topiramate 50, 100, and 200 mg/day, respectively, vs 42% for placebo), although the treatment differences did not reach nominal statistical significance. Topiramate 200 mg/day did not appear to offer greater efficacy than 100 mg/day. Treatment was generally well-tolerated, although adverse events were most frequent in the 200 mg/day dose group. CONCLUSIONS: This post hoc subset analysis suggests that topiramate 100 and 200 mg/day, and possibly 50 mg/day, administered prophylactically for 26 weeks may reduce migraine in adolescents.

Intracellular retention of caveolin 1 in presenilin-deficient cells.

Mutations in genes encoding presenilins (PS1 and PS2) are responsible for the majority of early onset familial Alzheimer's disease. PS, a critical component of gamma-secretase, is responsible for the intramembranous cleavage of amyloid precursor protein and Notch. Other physiological functions have been assigned to PS without any clear identification of the mechanisms underlying these multiple biological roles. The early embryonic lethality of PS1 and PS2 double knock-out (PS1/2 null) mice prevents the evaluation of physiological roles of PS. To investigate new functions for presenilins, we performed a proteomic approach by using cells derived from PS1/2 null blastocysts and wild type controls. We identified a presenilin-dependent cell-surface binding of albumin. Binding of albumin depends on intact caveolae on the cellular surface. Abnormal caveolin 1 localization in PS1/2 null cells was associated with a loss of caveolae and an absence of caveolin 1 expression within lipid rafts. Expressing PS1 or PS2 but not the intracellular form of Notch1 in PS1/2 null cells restored normal caveolin 1 localization, demonstrating that presenilins are required for the subcellular trafficking of caveolin 1 independently from Notch activity. Despite an expression of both caveolin 1 and PS1 within lipid raft-enriched fractions after sucrose density centrifugation in wild type cells, no direct interaction between these two proteins was detected, implying that presenilins affect caveolin 1 trafficking in an indirect manner. We conclude that presenilins are required for caveolae formation by controlling transport of intracellular caveolin 1 to the plasma membrane.

Recurrence risks for neural tube defects in siblings of patients with lipomyelomeningocele.

PURPOSE: Neural tube defects (NTDs) are a group of widely varying congenital malformations resulting from incomplete or improper fusion of the neural tube during embryonic development. NTDs are traditionally classified by the presence or absence of a layer of skin covering the spinal defect. Although a genetic component has been well established in the etiology of open NTDs, studies examining the genetics of closed NTDs such as lipomyelomeningocele are rare. We and others have previously observed families in which multiple members were affected with a broad spectrum of NTDs, suggesting the possibility of a common genetic etiology. METHODS: We calculated the sibling recurrence risk in 52 pedigrees in which the proband was diagnosed with lipomyelomeningocele (LMM), defining recurrence broadly to include both closed and open neural tube defects. RESULTS: Although no recurrences of LMM were observed among younger siblings, one younger sibling had myelomeningocele, yielding an estimate of recurrence risk of 0.04 (95% CI 0.01-0.20). When all siblings of the proband were included, two additional affected siblings were identified, one with anencephaly and another with fatty filum, yielding an estimate of recurrence risk of 0.043 (95% CI 0.01-0.12). CONCLUSIONS: Although the sample size is small, these data are not inconsistent with recurrence risks for myelomeningocele, ranging from 2% to 5% in siblings. These data suggest the underlying genetic basis for closed defects may be the same or closely related to that for myelomeningocele in some families, although a larger sample will be necessary before these data are appropriate for use in a clinical setting. Further characterizations, including whether risk for recurrence of NTDs or LMM in families in which the proband is affected with LMM are altered by folate supplementation, may shed light on the underlying genetics.

Notch pathway molecules are essential for the maintenance, but not the generation, of mammalian neural stem cells.

Neural stem cells, which exhibit self-renewal and multipotentiality, are generated in early embryonic brains and maintained throughout the lifespan. The mechanisms of their generation and maintenance are largely unknown. Here, we show that neural stem cells are generated independent of RBP-Jkappa, a key molecule in Notch signaling, by using RBP-Jkappa(-/-) embryonic stem cells in an embryonic stem cell-derived neurosphere assay. However, Notch pathway molecules are essential for the maintenance of neural stem cells; they are depleted in the early embryonic brains of RBP-Jkappa(-/-) or Notch1(-/-) mice. Neural stem cells also are depleted in embryonic brains deficient for the presenilin1 (PS1) gene, a key regulator in Notch signaling, and are reduced in PS1(+/-) adult brains. Both neuronal and glial differentiation in vitro were enhanced by attenuation of Notch signaling and suppressed by expressing an active form of Notch1. These data are consistent with a role for Notch signaling in the maintenance of the neural stem cell, and inconsistent with a role in a neuronal/glial fate switch.