Ketogenic diet in epileptic encephalopathies

Ketogenic diet: a therapeutic alternative in pediatric refractory epilepsies

Several studies have demonstrated the effectiveness of ketogenic diet (KD) on refractory epilepsies, especially in children. In this category of patients, a strong collaboration between the healthcare providers and the full engagement of parents is required. The regimen is significantly effective for different types of epilepsy that are resistant to medical treatment. It can also be used as a first-line treatment, given its well tolerance. Treatment has been rolled out for children but research into its use in adults is promising. There is no international or national protocol, the implementation of this diet follows a rigor being specific to every ketogenic center. The understanding of the underlying mechanisms is not well elucidated, it would make it possible to optimize the clinical use of the ketogenic diet, but also to develop novel antiepileptic treatments. This article aims to review the different variants of KD and their prescription terms in children with intractable epilepsy. Keywords: drug-resistant epilepsy, ketogenic diet, children, Modified Atkins Diet.

Metabolic Derangement in Pediatric Patient with Obesity: The Role of Ketogenic Diet as Therapeutic Tool

Obesity is defined as a condition characterized by an excessive fat accumulation that has negative health consequences. Pediatric obesity is associated with an increased risk for many diseases, including impaired glycemic and lipidic control that may lead to the development of chronic, and potentially disabling, pathologies, such as type 2 diabetes mellitus (T2DM) and cardiovascular events, in adult life. The therapeutic strategy initially starts with interventions that are aimed at changing lifestyle and eating behavior, to prevent, manage, and potentially reverse metabolic disorders. Recently, the ketogenic diet (KD) has been proposed as a promising dietary intervention for the treatment of metabolic and cardiovascular risk factors related to obesity in adults, and a possible beneficial role has also been proposed in children. KD is very low in carbohydrate, high in fat, and moderate to high in protein that may have the potential to promote weight loss and improve lipidic derangement, glycemic control, and insulin sensitivity. In this review, we present metabolic disorders on glycemic and lipidic control in children and adolescents with obesity and indication of KD in pediatrics, discussing the role of KD as a therapeutic tool for metabolic derangement. The results of this review may suggest the validity of KD and the need to further research its potential to address metabolic risk factors in pediatric obesity.

Novel Cellular Functions of Very Long Chain-Fatty Acids: Insight From ELOVL4 Mutations

Elongation of Very Long chain fatty acids-4 (ELOVL4) protein is a member of the ELOVL family of fatty acid elongases that is collectively responsible for catalyzing formation of long chain fatty acids. ELOVL4 is the only family member that catalyzes production of Very Long Chain Saturated Fatty Acids (VLC-SFA) and Very Long Chain Polyunsaturated Fatty Acids (VLC-PUFA) with chain lengths ≥28 carbons. ELOVL4 and its VLC-SFA and VLC-PUFA products are emerging as important regulators of synaptic signaling and neuronal survival in the central nervous system (CNS). Distinct sets of mutations in ELOVL4 cause three different neurological diseases in humans. Heterozygous inheritance of one set of autosomal dominant ELOVL4 mutations that leads to truncation of the ELOVL4 protein causes Stargardt-like macular dystrophy (STGD3), an aggressive juvenile-onset retinal degeneration. Heterozygous inheritance of a different set of autosomal dominant ELOVL4 mutations that leads to a full-length protein with single amino acid substitutions causes spinocerebellar ataxia 34 (SCA34), a late-onset neurodegenerative disease characterized by gait ataxia and cerebellar atrophy. Homozygous inheritance of a different set of ELOVL4 mutations causes a more severe disease with infantile onset characterized by seizures, spasticity, intellectual disability, ichthyosis, and premature death. ELOVL4 is expressed widely in the CNS and is found primarily in neurons. ELOVL4 is expressed in cell-specific patterns within different regions of the CNS that are likely to be related to disease symptoms. In the retina, ELOVL4 is expressed exclusively in photoreceptors and produces VLC-PUFA that are incorporated into phosphatidylcholine and enriched in the light sensitive membrane disks of the photoreceptor outer segments. VLC-PUFA are enzymatically converted into "elovanoid" compounds that appear to provide paracrine signals that promote photoreceptor and neuronal survival. In the brain, the main ELOVL4 products are VLC-SFA that are incorporated into sphingolipids and enriched in synaptic vesicles, where they regulate kinetics of presynaptic neurotransmitter release. Understanding the function of ELOVL4 and its VLC-SFA and VLC-PUFA products will advance our understanding of basic mechanisms in neural signaling and has potential for developing novel therapies for seizure and neurodegenerative diseases.

Current Perspectives On The Role Of The Ketogenic Diet In Epilepsy Management

Drug-refractory epilepsy is a commonly prevalent pediatric neurological illness of global significance. Ketogenic diet (KD) is a time-tested therapeutic modality for refractory epilepsy, which has reemerged as a robust alternative to anti-epileptic pharmacotherapy. There is a growing body of evidence which supports the anti-seizure efficacy, safety profile and feasibility of KD use in childhood epilepsy. In addition, this modality has been recognized to reduce anti-epileptic exposure, improve cognition and behavioral profile of patients as well as improve the quality-of-life of care-givers. Current indications of KD include refractory epilepsy syndromes, selected metabolic disorders (such as pyruvate dehydrogenase deficiency) and a host of varied neurological entities. KD research has broadened the knowledge-base about its mechanisms of action. Four types of KD are in vogue currently with varying nutritional constitution, palatability, administration protocols and comparable efficacy. KD initiation and maintenance are the result of concerted effort of a team of pediatric neurologist/epileptologist, nutritionist and patient's primary care-giver. Consensus is being formulated about various practical aspects of KD such as patient-selection, parental counseling, baseline work-up, dietary prescription, nutritional supplementation, concurrent anti-epileptic drug administration, follow-up and treatment-duration. Novel applications of KD include its use in neonatal epilepsy and super-refractory status epilepticus and tailor-made formulations such as cooking oil-based KD in predominantly rice-fed populations. Increasing body of clinical experience, improved nutritional designs and translational research are promoting KD as a major therapeutic modality. Currently, KD forms a core essence in the armamentarium against refractory epilepsy. In this review, we summarize the recent advances and current perspectives in the use of KD in refractory epilepsy.

Catabolism of (2E)-4-hydroxy-2-nonenal via ω- and ω-1-oxidation stimulated by ketogenic diet

Oxidative stress triggers the peroxidation of ω-6-polyunsaturated fatty acids to reactive lipid fragments, including (2E)-4-hydroxy-2-nonenal (HNE). We previously reported two parallel catabolic pathways of HNE. In this study, we report a novel metabolite that accumulates in rat liver perfused with HNE or 4-hydroxynonanoic acid (HNA), identified as 3-(5-oxotetrahydro-2-furanyl)propanoyl-CoA. In experiments using a combination of isotopic analysis and metabolomics studies, three catabolic pathways of HNE were delineated following HNE conversion to HNA. (i) HNA is ω-hydroxylated to 4,9-dihydroxynonanoic acid, which is subsequently oxidized to 4-hydroxynonanedioic acid. This is followed by the degradation of 4-hydroxynonanedioic acid via β-oxidation originating from C-9 of HNA breaking down to 4-hydroxynonanedioyl-CoA, 4-hydroxyheptanedioyl-CoA, or its lactone, 2-hydroxyglutaryl-CoA, and 2-ketoglutaric acid entering the citric acid cycle. (ii) ω-1-hydroxylation of HNA leads to 4,8-dihydroxynonanoic acid (4,8-DHNA), which is subsequently catabolized via two parallel pathways we previously reported. In catabolic pathway A, 4,8-DHNA is catabolized to 4-phospho-8-hydroxynonanoyl-CoA, 3,8-dihydroxynonanoyl-CoA, 6-hydroxyheptanoyl-CoA, 4-hydroxypentanoyl-CoA, propionyl-CoA, and acetyl-CoA. (iii) The catabolic pathway B of 4,8-DHNA leads to 2,6-dihydroxyheptanoyl-CoA, 5-hydroxyhexanoyl-CoA, 3-hydroxybutyryl-CoA, and acetyl-CoA. Both in vivo and in vitro experiments showed that HNE can be catabolically disposed via ω- and ω-1-oxidation in rat liver and kidney, with little activity in brain and heart. Dietary experiments showed that ω- and ω-1-hydroxylation of HNA in rat liver were dramatically up-regulated by a ketogenic diet, which lowered HNE basal level. HET0016 inhibition and mRNA expression level suggested that the cytochrome P450 4A are main enzymes responsible for the NADPH-dependent ω- and ω-1-hydroxylation of HNA/HNE.