Weight Change in Monozygotic Twins Treated with Valproate

Association of epilepsy, anti-epileptic drugs (AEDs), and type 2 diabetes mellitus (T2DM): a population-based cohort retrospective study, impact of AEDs on T2DM-related molecular pathway, and via peroxisome proliferator-activated receptor γ transactivation

Introduction

A potential association between epilepsy and subsequent type 2 diabetes mellitus (T2DM) has emerged in recent studies. However, the association between epilepsy, anti-epileptic drugs (AEDs), and the risk of T2DM development remains controversial. We aimed to conduct a nationwide, population-based, retrospective, cohort study to evaluate this relationship.

Methods

We extracted data from the Taiwan Longitudinal Generation Tracking Database of patients with new-onset epilepsy and compared it with that of a comparison cohort of patients without epilepsy. A Cox proportional hazards regression model was used to analyze the difference in the risk of developing T2DM between the two cohorts. Next-generation RNA sequencing was used to characterize T2DM-related molecularchanges induced by AEDs and the T2DM-associated pathways they alter. The potential of AEDs to induce peroxisome proliferator-activated receptor γ (PPARγ) transactivation was also evaluated.

Results

After adjusting for comorbidities and confounding factors, the case group (N = 14,089) had a higher risk for T2DM than the control group (N = 14,089) [adjusted hazards ratio (aHR), 1.27]. Patients with epilepsy not treated with AEDs exhibited a significantly higher risk of T2DM (aHR, 1.70) than non-epileptic controls. In those treated with AEDs, the risk of developing T2DM was significantly lower than in those not treated (all aHR ≤ 0.60). However, an increase in the defined daily dose of phenytoin (PHE), but not of valproate (VPA), increased the risk of T2DM development (aHR, 2.28). Functional enrichment analysis of differentially expressed genes showed that compared to PHE, VPA induced multiple beneficial genes associated with glucose homeostasis. Among AEDs, VPA induced the specific transactivation of PPARγ.

Discussion

Our study shows epilepsy increases the risk of T2DM development, however, some AEDs such as VPA might yield a protective effect against it. Thus, screening blood glucose levels in patients with epilepsy is required to explore the specific role and impact of AEDs in the development of T2DM. Future in depth research on the possibility to repurpose VPA for the treatment of T2DM, will offer valuable insight regarding the relationship between epilepsy and T2DM.

Polymorphisms of peroxisome proliferator-activated receptor γ (PPARγ) and cluster of differentiation 36 (CD36) associated with valproate-induced obesity in epileptic patients

RATIONALE

Valproate (VPA) is a choice for the treatment of primary generalized epilepsies and partial epilepsies. Unfortunately, weight gain or obesity is one of the most frequent adverse effects of VPA treatment. Genetic factors were shown to be involved in the effect.

OBJECTIVE

The aim of this study was to investigate the association of selected single nucleotide polymorphisms (SNPs) of cluster of differentiation 36 (CD36) and peroxisome proliferator-activated receptor γ (PPARγ) with VPA-induced weight gain and obesity in epileptic patients.

METHODS

A total of 225 Chinese Han epilepsy patients receiving VPA treatment were recruited in the study. Height and weight for the calculation of body mass index (BMI) were measured at the initiation of VPA therapy and in the follow-up examination. A BMI of 25 kg/m² or higher was defined as obesity on the basis of the World Health Organization (WHO) criteria for Asian populations. Four SNPs in CD36 (rs1194197, rs7807607) and PPARγ (rs10865710, rs2920502) were genotyped using the Sequenom^® MassArray iPlex platform.

RESULTS

About 19.6% of epileptic patients receiving VPA therapy were found to become obese. After covariate analysis of age, gender, sex, height, initial BMI, and VPA dosage, the CD36 rs1194197 C allele and rs7807607 T allele (OR, 0.31; 95%CI, 0.13-0.72; P = 0.009 and OR, 0.38; 95%CI; 0.18-0.83; P = 0.02, respectively) were identified as protective factors for VPA-induced obesity. The PPARγ rs10865710 C allele carriers were found to be less likely to suffer from VPA-induced obesity compared with GG genotype carriers (OR, 0.04; 95%CI, 0.01-0.12; P < 0.001). After a Bonferroni correction for multiple comparisons, the genotypic associations of CD36 rs1194197 and PPARγ rs10865710 and the allelic association of CD36 rs7807607 with obesity remained statistically significant.

CONCLUSIONS

Our data first indicated that CD36 and PPARγ polymorphisms may be associated with VPA-induced obesity and weight gain, suggesting that CD36 and PPARγ may have potential value in predicting VPA-induced obesity in Chinese Han epileptic patients.

The effects of valproate and topiramate use on serum insulin, leptin, neuropeptide Y and ghrelin levels in epileptic children

PURPOSE

Although some drugs used in the treatment of epilepsy are known to affect body weight, the hormonal factors responsible have not been sufficiently described. The purpose of this study was to compare insulin, leptin, neuropeptide Y and ghrelin levels in children with epilepsy receiving monotherapy with topiramate (TPM) and valproic acid (VPA), the drugs whose effects on body weight have been most discussed, with those of a control group.

METHOD

48 patients (25 VPA, 23 TPM) aged between 6 and 15.5 years, presenting to the Karadeniz Technical University Medical Faculty Pediatric Neurology Clinic, diagnosed with idiopathic epilepsy or location-related idiopathic epilepsy, and receiving VPA or TPM monotherapy for at least 6 months were included in the study. Twenty-five healthy subjects with similar demographic characteristics were enrolled as the control group. Blood samples were collected from the patient and control groups after fasting for at least 10-12 h and again 1 and 2 h postprandially. Body mass index (BMI) values were calculated for all cases. VPA levels, glucose, insulin, leptin, neuropeptide Y and ghrelin were investigated in all three separate blood samples.

RESULTS

Age, height, weight and BMI were similar between the patient and control groups. Significant weight gain was observed throughout treatment in the VPA group compared to the TPM group. High fasting and postprandial insulin levels were observed in the VPA group. VPA group leptin and neuropeptide Y (NPY) levels were also higher than in the TPM and control groups. No significant difference was determined in ghrelin levels in the patient groups compared to the controls.

CONCLUSION

Low blood sugar not being observed, even though insulin levels are high, after fasting and in the postprandial period in epileptic children receiving VPA is indicative of insulin resistance. The elevation in leptin and neuropeptide Y levels observed in the VPA group also suggest this.

The Investigation of Insulin Resistance in Two Groups of Epileptic Patients Treated with Sodium Valproate and Carbamazepine

BACKGROUND

Valproic acid (VPA) is a widely used broad-spectrum antiepileptic drug for therapy of generalized and focal epilepsies. Cross-sectional studies have suggested that valproate treatment may be associated with hyperinsulinemia. We decided to investigate hyperinsulinemia as a health-threatening side effect of VPA in Iranian epileptic patients.

MATERIALS AND METHODS

Body mass index (BMI), lipid profile, fasting serum insulin, fasting blood glucose (FBS), and homeostatic model assessment-insulin resistance (HOMA-IR) were measured in 30 VPA-treated epileptic patients and 30 controls (CBZ-treated). The Chi-square test, t-test, and Pearson correlation test were used.

RESULTS

BMI was higher in VPA group than in control group (25.7 ± 3.5 > 21.7 ± 4.1) (0.000 < 0.05). Prevalence of obesity was 16.6% in VPA group that was almost the same and even lower than general Iranian population. Serum triglyceride (TG) (150 ± 77.2) was higher than CBZ group (114 ± 35.2) (P = 0.023 < 0.05). However, serum high-density lipoprotein level was lower in VPA group than controls (45.2 ± 11.7 < 54.4 ± 13.9) (P = 0.008 < 0.05). Serum insulin, FBS, HOMA-IR, cholesterol, and low-density lipoprotein did not demonstrate statistically significant differences between the two groups (P > 0.05).

CONCLUSION

Despite the majority of previous studies that are against VPA and according to our study, VPA could be prescribed safely and it may not cause IR and its complications.

Association of LEPR and ANKK1 Gene Polymorphisms with Weight Gain in Epilepsy Patients Receiving Valproic Acid

BACKGROUND

Weight gain is the most frequent adverse effect of valproic acid (VPA) treatment, resulting in poor compliance and many endocrine disturbances. Similarities in the weight change of monozygotic twins receiving VPA strongly suggests that genetic factors are involved in this effect. However, few studies have been conducted to identify the relevant genetic polymorphisms. Additionally, the causal relationship between the VPA concentration and weight gain has been controversial. Thus, we investigated the effects of single nucleotide polymorphisms (SNPs) in several appetite stimulation and energy homeostasis genes and the steady state plasma concentrations (Css) of VPA on the occurrence of weight gain in patients.

METHODS

A total of 212 epilepsy patients receiving VPA were enrolled. Nineteen SNPs in 11 genes were detected using the Sequenom MassArray iPlex platform, and VPA Css was determined by high-performance liquid chromatography (HPLC).

RESULTS

After 6 months of treatment, 20.28% of patients were found to gain a significant amount of weight (weight gained ≥7%). Three SNPs in the leptin receptor (LEPR), ankyrin repeat kinase domain containing 1 (ANKK1), and α catalytic subunit of adenosine monophosphate-activated protein kinase (AMPK) showed significant associations with VPA-induced weight gain (p < 0.001, p = 0.017 and p = 0.020, respectively). After Bonferroni correction for multiple tests, the genotypic association of LEPR rs1137101, the allelic association of LEPR rs1137101, and ANKK1 rs1800497 with weight gain remained significant. However, the VPA Css in patents who gained weight were not significantly different from those who did not gain weight (p = 0.121).

CONCLUSIONS

LEPR and ANKK1 genetic polymorphisms may have value in predicting VPA-induced weight gain.

Weight-reducing side effects of the antiepileptic agents topiramate and zonisamide

Drug-induced weight alteration can be a serious side effect that applies to several therapeutic agents and must be referred to in the respective approved labeling texts. The side effect may become health threatening in case of significant weight change in either direction. Several antiepileptic drugs (AEDs) are associated with weight gain such as gabapentin, pregabalin, valproic acid, and vigabatrin and to some extent carbamazepine. Others are weight neutral such as lamotrigine, levetiracetam, and phenytoin or associated with slight weight loss as, e.g., felbamate. The focus of this chapter is on the two AEDs causing strong weight loss: topiramate and zonisamide. For both drugs, several molecular mechanisms of actions are published. We provide a review of these potential mechanisms, some of which are based on in vivo studies in animal models for obesity, and of clinical studies exploring these two drugs as single entities or in combinations with other agents.

Drug-induced toxicity on mitochondria and lipid metabolism: mechanistic diversity and deleterious consequences for the liver

Numerous investigations have shown that mitochondrial dysfunction is a major mechanism of drug-induced liver injury, which involves the parent drug or a reactive metabolite generated through cytochromes P450. Depending of their nature and their severity, the mitochondrial alterations are able to induce mild to fulminant hepatic cytolysis and steatosis (lipid accumulation), which can have different clinical and pathological features. Microvesicular steatosis, a potentially severe liver lesion usually associated with liver failure and profound hypoglycemia, is due to a major inhibition of mitochondrial fatty acid oxidation (FAO). Macrovacuolar steatosis, a relatively benign liver lesion in the short term, can be induced not only by a moderate reduction of mitochondrial FAO but also by an increased hepatic de novo lipid synthesis and a decreased secretion of VLDL-associated triglycerides. Moreover, recent investigations suggest that some drugs could favor lipid deposition in the liver through primary alterations of white adipose tissue (WAT) homeostasis. If the treatment is not interrupted, steatosis can evolve toward steatohepatitis, which is characterized not only by lipid accumulation but also by necroinflammation and fibrosis. Although the mechanisms involved in this aggravation are not fully characterized, it appears that overproduction of reactive oxygen species by the damaged mitochondria could play a salient role. Numerous factors could favor drug-induced mitochondrial and metabolic toxicity, such as the structure of the parent molecule, genetic predispositions (in particular those involving mitochondrial enzymes), alcohol intoxication, hepatitis virus C infection, and obesity. In obese and diabetic patients, some drugs may induce acute liver injury more frequently while others may worsen the pre-existent steatosis (or steatohepatitis).

Retrospective analysis of the effectiveness of first-line antiepileptic drugs for generalized onset and unclassified epileptic seizures in Chinese children

BACKGROUND AND PURPOSE

Based on the time until treatment failure, we retrospectively analyzed 389 children to compare the long-term effectiveness of first-line antiepileptic drugs (AEDs) in children with generalized onset or unclassified epileptic seizures.

METHODS

Analyses were based on time until treatment failure and time until remission.

RESULTS

In terms of time until treatment failure, the failure rates of topiramate and carbamazepine were higher than that of sodium valproate (p < 0.05). For time until 1-year remission, sodium valproate was found to be significantly better than either topiramate or carbamazepine (p < 0.05). For the subgroup with generalized onset epilepsy, sodium valproate was much better than either topiramate or carbamazepine (p < 0.05). No significant differences were found between topiramate and carbamazepine (p = 0.319). For unclassified epileptic seizures, no significant differences were found among the three AEDs.

CONCLUSION

Sodium valproate should be the drug of choice for patients with children with generalized onset, and no significant differences were found among the three AEDs in unclassified epileptic seizures.

Epilepsy pharmacogenetics

Large interindividual variation in efficacy and adverse effects of anti-epileptic therapy presents opportunities and challenges in pharmacogenomics. Although the first true association of genetic polymorphism in drug-metabolizing enzymes with anti-epileptic drug dose was reported 10 years ago, most of the findings have had little impact on clinical practice so far. Most studies performed to date examined candidate genes and were focused on candidate gene selection. Genome-wide association and whole-genome sequencing technologies empower hypothesis-free comprehensive screening of genetic variation across the genome and now the main challenge remaining is to select and study clinically relevant phenotypes suitable for genetic studies. Here we review the current state of epilepsy pharmacogenetics focusing on phenotyping questions and discuss what characteristics we need to study to get answers.

Body Mass Index and Serum Lipid Changes During Treatment with Valproic Acid in Children with Epilepsy

BACKGROUND

Valproic acid is the drug of choice for a wide variety of epileptic seizures and syndromes because of its broad spectrum of activity and because, in most patients, it is well tolerated. Although weight gain is a well-known adverse effect of valproic acid therapy, only a few studies have addressed weight gain associated with it in children aged 2–8 years.

OBJECTIVE

To evaluate valproic acid–associated changes in the body mass index (BMI) z-scores and to assess changes in serum triglyceride, cholesterol, and fasting glucose levels in young children receiving valproic acid treatment.

METHODS

Eighty-seven patients (39 females, 48 males) receiving valproic acid therapy for at least 3 months were included in the retrospective longitudinal study. Mean ± SD age at initiation of therapy was 4.8 ± 0.8 years. Changes in BMI z-scores as well as serum triglyceride, total cholesterol, and fasting glucose levels were evaluated as continuous variables and analyzed by longitudinal methods for all patients.

RESULTS

The average change from baseline in BMI z-scores was 0.80 (p = 0.001) at 3.1 years of follow-up. No significant change in triglyceride, cholesterol, and serum fasting glucose levels was observed over the same period. The percentage of overweight children at baseline was 6.9% and rose to 16% by the final visit (p = 0.081).

CONCLUSIONS

Valproic acid–associated weight gain may occur in young children. However, only 16% of patients were categorized as overweight at the end of the study; this percentage overlaps the percentage of overweight healthy young Italian children. The BMI z-scores significantly increased during the first 16 months of therapy, then appeared to level off. These observations may influence clinical practice and decision-making regarding suspending the drug due to weight gain in children in whom seizure control has been achieved. A For Our Patients summary of this article is available at www.ForOurPatients.info