A mechanistic approach to explore the neuroprotective potential of zonisamide in seizures

Zonisamide Ameliorated the Apoptosis and Inflammation in Cerebellar Tissue of Induced Alcohol Addiction Animal Model

This study investigated the effects of zonisamide treatment on cerebellar tissues in an experimental alcohol addiction (AA) model and its potential mechanisms of action, particularly regarding apoptotic protease activating factor-1 (APAF-1) and tumor necrosis factor-alpha (TNF-α) expression. Thirty rats were divided into three groups: sham, ethanol (EtOH), and EtOH + zonisamide. AA was induced by administering 6 cc of EtOH orally every 8 h for 4 days. Zonisamide (100 mg/kg) was given to rats once daily before EtOH administration. Motor defects were evaluated using an open field maze. Serum TNF-α levels were measured from blood samples. Cerebellar sections were processed for histological examination and immunostained for APAF-1 and TNF-α. Protein interaction networks were constructed using Cytoscape, and functional annotations were performed with ShinyGO (version 0.80) software. The traveled area in the EtOH group was significantly reduced compared to the sham group (p = 0.0005). Rats in the EtOH + zonisamide group covered a larger area, with zonisamide treatment significantly improving locomotor ability compared to the EtOH group (p = 0.0463). Serum TNF-α levels were significantly elevated in the EtOH group compared to the sham group (p < 0.0001) and were significantly decreased in the EtOH + zonisamide group compared to the EtOH group (p = 0.0309). Regular cerebellar histological layers were observed in the sham group, while EtOH induction caused loss of cerebellar tissue integrity, neuronal degeneration, vascular dilatation and congestion, reduced myelin density, and neuropils in the EtOH group. Zonisamide treatment improved these pathologies, enhancing myelination and neuropil formation. Negative APAF-1 and TNF-α expressions were observed across cerebellar layers in the sham group. Due to EtOH toxicity, APAF-1 and TNF-α expression were upregulated in the EtOH group compared to the sham group (p < 0.001 for both). Zonisamide treatment downregulated these protein expressions in the EtOH + zonisamide group compared to the EtOH group (p < 0.001 and p = 0.0087, respectively). APAF-1 was primarily associated with AA through antifolate resistance, endopeptidases, and the interleukin-1 pathway, while TNF-α was predominantly enriched in infections and choline-binding, indicating zonisamide's impact on immune and inflammatory pathways. In conclusion, zonisamide treatment significantly mitigated ethanol-induced cerebellar damage and inflammation in an AA model. Zonisamide improved locomotor function and reduced serum TNF-α levels, as well as APAF-1 and TNF-α expression in cerebellar tissues. These findings suggest that zonisamide exerts its protective effects by modulating immune and inflammatory pathways, thereby preserving cerebellar integrity and function.

An Investigation of the Effects of Chronic Zonisamide, Sultiam, Lacosamide, Clobazam, and Rufinamide Antiseizure Drugs on Foliculogenesis in Ovarian Tissue in Prepubertal Non-Epileptic Rats

We aimed to determine the morphological and histological effects of zonisamide, sultiam, lacosamide, clobazam, and rufinamide on ovarian folliculogenesis in rats. Sixty female Wistar rats were equally divided into 6 experimental groups, including control group, zonisamide, sultiam, lacosamide, clobazam, and rufinamide were administered by gavage for 90 days. According to the daily vaginal smears of the rats in the proestrus and diester phases of the estrus cycle, their ovaries were removed and placed in the fixation solution. Immunohistochemical and apoptosis staining protocols were applied. The number of healthy follicles in the control group was found to be statistically significantly higher when compared to the antiseizure drug groups (p<0.001). The number of corpus luteum was found to be statistically significantly lower in the control group when compared with the anti-seizure drug groups (p<0.001). There was a significant difference in the number of TUNEL positive apoptotic follicles between the control and drug groups (p<0.001). There was a significant difference in the number of TUNEL positive apoptotic follicles between the control and drug groups (p<0.001). HSCORE, immunohistochemical EGF, IGF-1 and GDF-9 staining, a very strong immunoreaction was observed in the ovarian multilaminar primary follicle granulosa cells and oocytes in the control group (p<0.001), and an immunoreaction ranging from weak to medium was observed in the antiseizure drug groups. Long-term anti-seizure drug therapy with zonisamide, sultiam, lacosamide, clobazam, and rufinamide from prepubertal to adulthood causes apoptosis and disruption of folliculogenesis in the ovarian follicles of nonepileptic rats.

Ion-Channel Antiepileptic Drugs: An Analytical Perspective on the Therapeutic Drug Monitoring (TDM) of Ezogabine, Lacosamide, and Zonisamide

The term seizures includes a wide array of different disorders with variable etiology, which currently represent one of the most important classes of neurological illnesses. As a consequence, many different antiepileptic drugs (AEDs) are currently available, exploiting different activity mechanisms and providing different levels of performance in terms of selectivity, safety, and efficacy. AEDs are currently among the psychoactive drugs most frequently involved in therapeutic drug monitoring (TDM) practices. Thus, the plasma levels of AEDs and their metabolites are monitored and correlated to administered doses, therapeutic efficacy, side effects, and toxic effects. As for any analytical endeavour, the quality of plasma concentration data is only as good as the analytical method allows. In this review, the main techniques and methods are described, suitable for the TDM of three AEDs belonging to the class of ion channel agents: ezogabine (or retigabine), lacosamide, and zonisamide. In addition to this analytical overview, data are provided, pertaining to two of the most important use cases for the TDM of antiepileptics: drug–drug interactions and neuroprotection activity studies. This review contains 146 references.

Zonisamide Therapy Reduces Metabolic Consequences and Diminishes Nonalcoholic Fatty Liver Disease in Patients with Epilepsy

Antiepileptic drugs that can reduce aberrant metabolism are beneficial for patients. Zonisamide (ZNS) is a chemical with antiepileptic and antioxidant activities. Here, we evaluate the efficacy of ZNS therapy on reducing obesity and decreasing risks of vascular diseases and hepatic steatosis. Clinical and metabolic indicators including body weight, body mass index (BMI), serum lipid profiles, glycated hemoglobin (HbA1c), homocysteine, and an inflammatory marker, high-sensitivity C-reactive protein (hs-CRP), were assessed at baseline and at the end of 12 and 24 weeks of treatment. Nonalcoholic fatty liver disease was evaluated using the hepatic steatosis index (HSI). A body weight reduction of ≥5% was observed in 24.6% and 32.8% of patients after 12 and 24 weeks of ZNS treatment, respectively. After adjusting for age, sex, time, and the corresponding dependent variable at baseline, the generalized estimating equation analysis revealed that the body weight, BMI, serum levels of HbA1c, triglycerides, hs-CRP, and the index for HSI were significantly declined. These results suggest that ZNS provides benefits in patients with obesity and metabolic syndrome at high vascular risk.

A combo-strategy to improve brain delivery of antiepileptic drugs: Focus on BCRP and intranasal administration

The breast cancer resistance protein (BCRP) is an efflux transporter expressed at the apical surface of human brain endothelial cells of the blood-brain barrier (BBB). It was proposed as one of the transporters responsible for the development of drug resistance to several central nervous system (CNS) drugs, including antiepileptic drugs (AEDs). In this context, the present work aimed to characterize the interaction between new-generation AEDs, lacosamide, levetiracetam and zonisamide, and BCRP, in order to investigate whether intranasal administration can successfully avoid the impact of BCRP on brain drug distribution, preventing the development of refractory epilepsy. Firstly, BCRP substrates and/or inhibitors were identified resorting to intracellular accumulation and bidirectional transport assays on Madin-Darby canine kidney (MDCK) cells and the transfected cell line with human ABCG2 (MDCK-BCRP). Furthermore, in vivo pharmacokinetic studies were carried out for BCRP substrates with and without elacridar, a well-known P-gp and BCRP modulator, to assess the impact of efflux inhibition on brain drug distribution. The extent of drug equilibration between plasma and brain was compared after intravenous (IV) and intranasal administration to mice. Among the three tested AEDs, zonisamide was the only AED identified as BCRP substrate in vitro, as demonstrated by the net flux ratio of 2.73, which decreased 53.85 % in the presence of a BCRP inhibitor, Ko143. Lacosamide revealed to inhibit BCRP in all tested concentrations (2.5-75 µM), exhibiting a significant increase (p < 0.001) of the intracellular accumulation of a BCRP substrate (Hoechst 33342) in MDCK-BCRP cells. Levetiracetam did not behave as a BCRP substrate nor inhibitor. After IV administration, the plasma concentrations of zonisamide were unaffected by elacridar, but its extent of brain exposure increased three-fold (as assessed by AUC_t, 674.12 vs 284.47 µg.min/mL). These results corroborate the previous in vitro findings, suggesting that BCRP is involved in the transport of zonisamide through the BBB. In opposition, no significant changes were found in plasma or brain concentrations after the administration of zonisamide by intranasal route, indicating that the influence of BCRP is less relevant than for IV route. In addition, direct nose-to-brain delivery of zonisamide, given by the direct transport percentage, was approximately 49 %. Altogether, these assays demonstrated that the impact of BCRP on the delivery of zonisamide to the brain is lower after intranasal administration, probably due to direct nose-to-brain transport. Therefore, the intranasal administration of AEDs may be a relevant strategy to avoid the impact of efflux transporters at the BBB and the development of drug resistance.

Pharmacological management of dementia with Lewy bodies with a focus on zonisamide for treating parkinsonism

INTRODUCTION

Dementia with Lewy bodies (DLB) has no approved symptomatic or disease-modifying treatments in the US and Europe, despite being the second most common cause of neurodegenerative dementia.

AREAS COVERED

Herein, the authors briefly review the DLB drug development pipeline, providing a summary of the current pharmacological intervention studies. They then focus on the anticonvulsant zonisamide, a benzisoxazole derivative with a sulfonamide group and look at its value for treating parkinsonism in DLB.

EXPERT OPINION

Several new compounds are being tested in DLB, the most innovative being those aimed at decreasing brain accumulation of α-synuclein. Unfortunately, new drug testing is challenging in terms of consistent diagnostic criteria and lack of reliable biomarkers. Few randomized controlled trials (RCTs) are well-designed, with enough power to detect significant drug effects. Levodopa monotherapy can treat the parkinsonism in DLB, but it can cause agitation or visual hallucination worsening. Two Phase II/III RCTs of DLB patients recently reported a statistically significant improvement in motor function in those receiving zonisamide as an adjunctive treatment to levodopa. New biomarker strategies and validated outcome measures for DLB or prodromal DLB may enhance clinical trial design for the development of specific disease-modifying treatments.

Treatment of status epilepticus with zonisamide: A multicenter cohort study of 34 patients and review of literature

INTRODUCTION

We present a summary of clinical cases of oral zonisamide (ZNS) used to treat refractory and super-refractory episodes of status epilepticus (SE).

METHODS

Zonisamide administration in SE was identified in the clinical records of patients treated in Frankfurt and Marburg between 2011 and 2017.

RESULTS

Zonisamide was administered during a total of 37 SE episodes in 34 patients with a mean age of 58.7 ± 17.8 years, 21 of them were female (61.7%). The median latency from the onset of SE to administration of ZNS was 6.3 days. Patients had already undergone unsuccessful treatment with a median of three other antiseizure drugs (ASDs). The median initial dose of ZNS was 100 mg/d, titrated to a median maintenance dose of 400 mg/d. Patients underwent ZNS treatment for a median period of 7 days. Zonisamide was the final drug administered in 9 of 37 (24.3%) episodes, with a clinical effect attributed to ZNS observed in 6 of 37 (16.2%) episodes. An effect attributed to ZNS was observed in 5 out of 30 episodes of refractory SE (RSE) and in one out of 7 episodes of super-refractory SE (SRSE). Possible negative side effects of ZNS were observed in two patients (one patient each with ataxia and skin rash). The mortality rate in hospitalized patients was 10.4% (n = 4).

CONCLUSION

The rate of SE resolution attributed to ZNS treatment (16.2%) can be considered relevant, particularly since ZNS treatment tends to be administered only after several other options have been tried, and has a treatment latency of over six days. Zonisamide may therefore be considered as an alternative oral treatment option in RSE and SRSE.