How can antiepileptic drugs affect bone mass, structure and metabolism? Lessons from animal studies

SummaryPatients with epilepsy, treated with antiepileptic drugs (AEDs) are at increased risk of fractures. Although several commonly used AEDs reduce bone mass in patients, the mechanisms are only scarcely known. In this review, we focus on the usefulness of animal models to explore the skeletal effects of AEDs. Moreover, we report our findings from a recent study comparing the effect of levetiracetam (LEV), phenytoin (PHT) and valproate (VPA) on various aspects of bone health in actively growing female rats. Our data indicate that these AEDs act differently on bone mass, structure and metabolism. A novel finding is that LEV reduces bone strength and bone formation without altering bone mass. Based on these results we propose that epidemiological fracture studies of patients treated with LEV are needed, and that these patients should be evaluated regularly to identify possible bone-related side effects

Long-term levetiracetam treatment affects reproductive endocrine function in female Wistar rats

SummaryPurposeSeveral antiepileptic drugs (AEDs) induce changes in endocrine function in women with epilepsy. Levetiracetam (LEV) is one of the newer AEDs, and to date no endocrine side-effects have been reported in humans. However, a recent study on ovarian follicular cells from prepubertal pigs showed that LEV affected basal steroid hormone secretion. The aim of the present study was to investigate possible effects of the drug on endocrine function and ovarian morphology in non-epileptic rats.MethodsThirty female Wistar rats were fed per-orally with either 50mg/kg LEV (n=15) or 150mg/kg LEV (n=15) twice daily for 90–95 days. Twenty rats received a control solution. The rats were killed in the dioestrus phase of the oestrous cycle. Serum concentrations of testosterone, 17β-oestradiol, progesterone, follicle stimulating hormone (FSH), luteinizing hormone (LH) and LEV were measured, and the ovaries examined histologically.ResultsMean ovarian weight showed a significant, dose-dependent increase after LEV treatment. Mean numbers of ovarian follicular cysts were not changed, but the numbers of corpora lutea and secondary follicles were significantly higher in the treated animals. Serum testosterone was significantly increased in treated animals (0.50nmol/l versus 0.16nmol/l in controls, p<0.05), while oestradiol was reduced (67.4 compared to 257.5pmol/l in controls, p<0.05). The low-dose group had significantly lower serum progesterone concentrations than the control group (56.8nmol/l versus 34.7nmol/l, respectively, p<0.05). FSH was reduced in the treated animals (3.3ng/ml versus 5.5ng/ml, p<0.05) while LH was unaffected.ConclusionOur findings indicate a possible effect of LEV on the hypothalamic–pituitary–gonadal (HPG) axis and ovarian morphology in non-epileptic rats. The effects differ from those previously described for other AEDs. Caution must be taken before these results can be applied to humans

Common genetic variation and susceptibility to partial epilepsies: a genome-wide association study

Partial epilepsies have a substantial heritability. However, the actual genetic causes are largely unknown. In contrast to many other common diseases for which genetic association-studies have successfully revealed common variants associated with disease risk, the role of common variation in partial epilepsies has not yet been explored in a well-powered study. We undertook a genome-wide association-study to identify common variants which influence risk for epilepsy shared amongst partial epilepsy syndromes, in 3445 patients and 6935 controls of European ancestry. We did not identify any genome-wide significant association. A few single nucleotide polymorphisms may warrant further investigation. We exclude common genetic variants with effect sizes above a modest 1.3 odds ratio for a single variant as contributors to genetic susceptibility shared across the partial epilepsies. We show that, at best, common genetic variation can only have a modest role in predisposition to the partial epilepsies when considered across syndromes in Europeans. The genetic architecture of the partial epilepsies is likely to be very complex, reflecting genotypic and phenotypic heterogeneity. Larger meta-analyses are required to identify variants of smaller effect sizes (odds ratio <1.3) or syndrome-specific variants. Further, our results suggest research efforts should also be directed towards identifying the multiple rare variants likely to account for at least part of the heritability of the partial epilepsies. Data emerging from genome-wide association-studies will be valuable during the next serious challenge of interpreting all the genetic variation emerging from whole-genome sequencing studie

Common genetic variation and susceptibility to partial epilepsies: a genome-wide association study

Partial epilepsies have a substantial heritability. However, the actual genetic causes are largely unknown. In contrast to many other common diseases for which genetic association-studies have successfully revealed common variants associated with disease risk, the role of common variation in partial epilepsies has not yet been explored in a well-powered study. We undertook a genome-wide association-study to identify common variants which influence risk for epilepsy shared amongst partial epilepsy syndromes, in 3445 patients and 6935 controls of European ancestry. We did not identify any genome-wide significant association. A few single nucleotide polymorphisms may warrant further investigation. We exclude common genetic variants with effect sizes above a modest 1.3 odds ratio for a single variant as contributors to genetic susceptibility shared across the partial epilepsies. We show that, at best, common genetic variation can only have a modest role in predisposition to the partial epilepsies when considered across syndromes in Europeans. The genetic architecture of the partial epilepsies is likely to be very complex, reflecting genotypic and phenotypic heterogeneity. Larger meta-analyses are required to identify variants of smaller effect sizes (odds ratio <1.3) or syndrome-specific variants. Further, our results suggest research efforts should also be directed towards identifying the multiple rare variants likely to account for at least part of the heritability of the partial epilepsies. Data emerging from genome-wide association-studies will be valuable during the next serious challenge of interpreting all the genetic variation emerging from whole-genome sequencing studies

GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment

APOE status and its association to learning and memory performance in middle aged and older Norwegians seeking assessment for memory deficits

Background We examined the hypothesis that deficits in learning, memory, and other cognitive functions are associated with the ε4 allele of the Apolipoprotein E (APOE) gene in a non-demented sample with memory complaints recruited from a population with a high prevalence of this allele. Methods The study group comprised 70 consecutively referred patients aged 50–75 seeking assessment due to memory complaints. They were screened for dementia, for neurological and psychiatric disease, and for cerebral infarction using Magnet Resonance Imaging (MRI). Participants were classified as non-demented based on clinical evaluation and results on cognitive tests. Results APOE ε4 carriers (56% of the sample) showed poorer performance than non-carriers on the Mini Mental State Examination, a number of measures of verbal memory function from the California Verbal Learning Test, and visual recall. In 46% of the participants, psychometric criteria for amnestic Mild Cognitive Impairment (aMCI) were satisfied. Conclusion Findings may be partly explained by a significant number of participants being in a preclinical phase of Alzheimer's disease. The observed deficits in learning performance and the lack of significant age modulation of the genetic association suggest a more general genetic effect. The findings are consistent with known neurobiological function of APOE ε4, including both increased risk of neurodegenerative disease and reduced synaptic integrity in older age

Is Temporal Lobe Epilepsy with childhood febrile seizures a distinctive entity? A comparative study

AbstractObjectivePharmacoresistance continues to be a major challenge in Temporal Lobe Epilepsies (TLE). A key to overcome pharmacoresistance is to identify subgroups among the TLE and disclose their specific molecular pathways. This will facilitate a tailored pharmacological treatment and improve outcome. There is growing evidence in favor of the theory that TLE with childhood febrile seizures (TLE-FS) may represent one distinctive subgroup among the TLE.Material and methodsWe compared clinical features from 102 TLE-FS patients with 105 TLE patients without FS. We also conducted a logistic regression analysis to adjust for possible confounders caused by overrepresentation of patients with Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) in the TLE-FS group.ResultsMTLE-HS was overrepresented in patients with TLE-FS (p=0.043). Age at epilepsy onset was lower in patients with TLE-FS (p<0.001). TLE-FS patients had a higher frequency of first grade family members with FS (p=0.003, adjusted for MTLE-HS: p=0.002). They were more frequently plagued with simple partial seizures (p=0.015, adjusted: p=0.038), and especially with vertiginous symptoms (p=0.004 adjusted: p=0.006). They also had the higher frequency of autonomic symptoms (p=0.003; adjusted: p=0.012), and more generalized tonic–clonic seizures (0.034; adjusted p=0.038).ConclusionWe identified TLE-FS as a phenotype that can be delineated from other TLE. None of the characteristics are specific, but we disclosed a set of features also when adjusted for MTLE-HS

The Combination of Dysexecutive and Amnestic Deficits Strongly Predicts Conversion to Dementia in Young Mild Cognitive Impairment Patients: A Report from the Gothenburg-Oslo MCI Study

Background/Aims: The present study aimed to add to the knowledge of mild cognitive impairment (MCI) by studying the prognosis in a relatively young cohort of patients characterized by neuropsychological criteria. Methods: Patients (mean age: 63 years) with cognitive complaints and MCI (n = 302) were recruited from two university clinics and followed for 2 years. Results: Pure dysexecutive MCI occurred in 11.7% of the neuropsychologically impaired patients, while 59.3 and 29.0% were characterized as having pure amnestic MCI or multidomain MCI. During the study period, the state of 2 (10.5%) of the patients with single-domain dysexecutive MCI converted to dementia, while 28 (29.2%) of the patients with pure amnestic MCI became demented. Of the patients with both executive and amnestic deficits, 28 (59.6%) became demented. Conclusion: The results suggest that dysexecutive symptoms in combination with amnestic symptoms constitute a strong risk factor for dementia in young MCI patients. A significant number of patients in all subgroups showed normal test results at follow-up, indicating that a neuropsychological diagnosis needs to be supported by imaging or biomarker data

Onset of epilepsy and menarche—Is there any relationship?

SummaryPurposeWomen with epilepsy have increased frequency of reproductive health problems compared to women without epilepsy. In puberty, reproductive hormonal changes during sexual maturation may affect epilepsy and induce the debut of seizures as indicated in some studies. On the other hand, epileptic activity affects sex hormone function, which may induce alterations in pubertal endocrine maturation and thereby menarche age. We wanted to investigate the relation between epilepsy and menarche age in a larger population of female epilepsy patients.MethodsA retrospective, questionnaire study of a cohort of 265 female outpatients from three Norwegian hospitals and 142 controls, aged 18–45 years was conducted. Parameters regarding epilepsy and reproductive health issues were registered. Perimenarche was defined as 2 years before and 2 years after the year of menarche.ResultsThere was a significantly higher frequency of patients with epilepsy debut between 10 and 18 year compared to 0–9 years (p<0.01). There was, however, no significant difference in occurrence of epilepsy debut in the perimenarche period compared to the 5 year periods before and after perimenarche, and no significant difference in epilepsy debut in the year of menarche compared to the 5 years before or after. Menarche age was not significantly different in those with epilepsy debut before or after menarche. Epilepsy type (idiopathic generalised or partial) did not influence the menarche age.ConclusionsThe study did not confirm the former observations of clustering of epilepsy debut at menarche or in the perimenarche period or alterations in menarche age in girls with epilepsy. However, onset of epilepsy is more frequent in the adolescent years (10–18), than in childhood (0–9)