Pharmacokinetic evaluation of vigabatrin dose for the treatment of refractory focal seizures in children using adult and pediatric data

Tuberous sclerosis complex and epilepsy in infancy: prevention and early diagnosis

Numerous studies showed that epilepsy represents a high burden in Tuberous Sclerosis Complex (TSC), affecting 63 to 78% of the patients. Epilepsy will be refractory to medication in over 60% of cases in early presentations, and accompanied by intellectual disabilities and/or autism spectrum disorders. The emerging experimental and clinical data suggest that the molecular and cellular changes triggered by seizures, particularly during the first weeks of life, can be limited by early action. Making any effort to avoid or delay epilepsy onset is a promising pathway to improve global outcome for TSC patients, although it is not possible to tidy up the specific roles of seizures, interictal abnormalities, and cortical abnormalities upon neurodevelopment. Early diagnosis of epilepsy can be made during a "symptomatic phase," shortly after the onset of seizures (focal seizures or spasms), revealing the TSC in a young infant. As soon as the diagnosis is made, a treatment with Vigabatrin is now recommended. The diagnosis of epilepsy can also be performed during a "presymptomatic phase", with the improvement of fetal and neonatal diagnosis of TSC. Recent studies demonstrated a significant delay of more than 3 months between the detection of EEG abnormalities and the first clinical seizures, which allows to consider a preventive treatment. Beside vigabatrin, mTOR inhibitors may have a place in this early management. The last recommendations about early detection and treatment of epilepsy in TSC will be detailed in this review. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Updated International Tuberous Sclerosis Complex Diagnostic Criteria and Surveillance and Management Recommendations

BACKGROUND

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease affecting multiple body systems with wide variability in presentation. In 2013, Pediatric Neurology published articles outlining updated diagnostic criteria and recommendations for surveillance and management of disease manifestations. Advances in knowledge and approvals of new therapies necessitated a revision of those criteria and recommendations.

METHODS

Chairs and working group cochairs from the 2012 International TSC Consensus Group were invited to meet face-to-face over two days at the 2018 World TSC Conference on July 25 and 26 in Dallas, TX, USA. Before the meeting, working group cochairs worked with group members via e-mail and telephone to (1) review TSC literature since the 2013 publication, (2) confirm or amend prior recommendations, and (3) provide new recommendations as required.

RESULTS

Only two changes were made to clinical diagnostic criteria reported in 2013: "multiple cortical tubers and/or radial migration lines" replaced the more general term "cortical dysplasias," and sclerotic bone lesions were reinstated as a minor criterion. Genetic diagnostic criteria were reaffirmed, including highlighting recent findings that some individuals with TSC are genetically mosaic for variants in TSC1 or TSC2. Changes to surveillance and management criteria largely reflected increased emphasis on early screening for electroencephalographic abnormalities, enhanced surveillance and management of TSC-associated neuropsychiatric disorders, and new medication approvals.

CONCLUSIONS

Updated TSC diagnostic criteria and surveillance and management recommendations presented here should provide an improved framework for optimal care of those living with TSC and their families.

Modulation of vigabatrin induced cerebellar injury: the role of caspase-3 and RIPK1/RIPK3-regulated cell death pathways

Vigabatrin is the drug of choice in resistant epilepsy and infantile spasms. Ataxia, tremors, and abnormal gait have been frequently reported following its use indicating cerebellar involvement. This study aimed, for the first time, to investigate the involvement of necroptosis and apoptosis in the VG-induced cerebellar cell loss and the possible protective role of combined omega-3 and vitamin B12 supplementation. Fifty Sprague-Dawley adult male rats (160-200 g) were divided into equal five groups: the control group received normal saline, VG200 and VG400 groups received VG (200 mg or 400 mg/kg, respectively), VG200 + OB and VG400 + OB groups received combined VG (200 mg or 400 mg/kg, respectively), vitamin B12 (1 mg/kg), and omega-3 (1 g/kg). All medications were given daily by gavage for four weeks. Histopathological changes were examined in H&E and luxol fast blue (LFB) stained sections. Immunohistochemical staining for caspase-3 and receptor-interacting serine/threonine-protein kinase-1 (RIPK1) as well as quantitative real-time polymerase chain reaction (qRT-PCR) for myelin basic protein (MBP), caspase-3, and receptor-interacting serine/threonine-protein kinase-3 (RIPK3) genes were performed. VG caused a decrease in the granular layer thickness and Purkinje cell number, vacuolations, demyelination, suppression of MBP gene expression, and induction of caspases-3, RIPK1, and RIPK3 in a dose-related manner. Combined supplementation with B12 and omega-3 improved the cerebellar histology, increased MBP, and decreased apoptotic and necroptotic markers. In conclusion, VG-induced neuronal cell loss is dose-dependent and related to both apoptosis and necroptosis. This could either be ameliorated (in low-dose VG) or reduced (in high-dose VG) by combined supplementation with B12 and omega-3.

Impact of enantiomer-specific changes in pharmacokinetics between infants and adults on the target concentration of racemic ketorolac: A pooled analysis

Aims

Ketorolac is a nonsteroidal anti‐inflammatory racemic drug with analgesic effects only attributed to its S‐enantiomer. The aim of this study is to quantify enantiomer‐specific maturational pharmacokinetics (PK) of ketorolac and investigate if the contribution of both enantiomers to the total ketorolac concentration remains equal between infants and adults or if a change in target racemic concentration should be considered when applied to infants.

Methods

Data were pooled from 5 different studies in adults, children and infants, with 1020 plasma concentrations following single intravenous ketorolac administration. An allometry‐based enantiomer‐specific population PK model was developed with NONMEM 7.3. Simulations were performed in typical adults and infants to investigate differences in S‐ and R‐ketorolac exposure.

Results

S‐ and R‐ketorolac PK were best described with a 3‐ and a 2‐compartment model, respectively. The allometry‐based PK parameters accounted for changes between populations. No maturation function of ketorolac clearance could be identified. All model parameters were estimated with adequate precision (relative standard error <50%). Single dose simulations showed that a previously established analgesic concentration at half maximal effect in adults of 0.37 mg/L, had a mean S‐ketorolac concentration of 0.057 mg/L, but a mean S‐ketorolac concentration of 0.046 mg/L in infants. To match the effective adult S‐ketorolac‐concentration (0.057 mg/L) in typical infants, the EC_50‐racemic should be increased to 0.41 mg/L.

Conclusion

Enantiomer‐specific changes in ketorolac PK yield different concentrations and S‐ and R‐ketorolac ratios between infants and adults at identical racemic concentrations. These PK findings should be considered when studies on maturational pharmacodynamics are considered.