Does the effectiveness of the ketogenic diet in different epilepsies yield insights into its mechanisms?

The interplay between microbiota and brain-gut axis in epilepsy treatment

The brain-gut axis plays a vital role in connecting the cognitive and emotional centers of the brain with the intricate workings of the intestines. An imbalance in the microbiota-mediated brain-gut axis extends far beyond conditions like Irritable Bowel Syndrome (IBS) and obesity, playing a critical role in the development and progression of various neurological disorders, including epilepsy, depression, Alzheimer's disease (AD), and Parkinson's disease (PD). Epilepsy, a brain disorder characterized by unprovoked seizures, affects approximately 50 million people worldwide. Accumulating evidence suggests that rebuilding the gut microbiota through interventions such as fecal microbiota transplantation, probiotics, and ketogenic diets (KD) can benefit drug-resistant epilepsy. The disturbances in the gut microbiota could contribute to the toxic side effects of antiepileptic drugs and the development of drug resistance in epilepsy patients. These findings imply the potential impact of the gut microbiota on epilepsy and suggest that interventions targeting the microbiota, such as the KD, hold promise for managing and treating epilepsy. However, the full extent of the importance of microbiota in epilepsy treatment is not yet fully understood, and many aspects of this field remain unclear. Therefore, this article aims to provide an overview of the clinical and animal evidence supporting the regulatory role of gut microbiota in epilepsy, and of potential pathways within the brain-gut axis that may be influenced by the gut microbiota in epilepsy. Furthermore, we will discuss the recent advancements in epilepsy treatment, including the KD, fecal microbiota transplantation, and antiseizure drugs, all from the perspective of the gut microbiota.

Increase of Human Milk Fat Inducing Nutritional Ketosis in Exclusively Breastfed Infant, Brought About by Treating the Mother With Ketogenic Dietary Therapy

INTRODUCTION

Medicalized Ketogenic Therapy is commonly used to treat refractory epilepsy. Patients have varying degrees of seizure or symptom relief, responding at individual levels of ketone production. Typically, initiating the therapy necessitates the discontinuation of breastfeeding. Our case study mother was keen to continue breastfeeding if possible. We were able to achieve this by placing the healthy mother on a ketogenic diet and altering the composition of the mother's own milk.

MAIN LACTATION ISSUE

Pediatric Medicalized Ketogenic Therapy is delivered through a ketogenic diet consisting of up to 90% fat, measuring of ingredients to 0.1 g matching a food prescription of fat, protein, and carbohydrate. We placed the mother on a less stringent ketogenic diet achieving 61% fat and measured both infant and mother's blood sugar levels and ketones. The hypothesis was that changes would occur in the mother's own milk fat content, and/or ketones would be passed directly to the infant. If therapeutic levels of ketones were reached in the infant and a reduction in seizures observed, breastfeeding could continue.

MANAGEMENT OVERVIEW

Over 3 months we achieved a calorific increase of the mother's mature milk by an additional 134%. The infant was successfully put into nutritional ketosis and visible seizures eliminated.

CONCLUSION

Medicalized Ketogenic Therapy can be safely used to treat seizures of breastfeeding infants diagnosed with epilepsy, through management of the mother on a ketogenic diet. Significantly increasing the mature mothers own milk fat component could have implications for other areas, including faltering growth.

Medical treatment of tuberous sclerosis-related epilepsy

Epilepsy is one of the most frequent CNS manifestations of tuberous sclerosis, and for most patients, it is the major debilitating factor. In up to 70% of the cases, the epilepsy is refractory and usually associated with significant behavioral as well as developmental consequences. Therefore, controlling seizures is one of the biggest medical and surgical challenges. Understanding the cellular mechanism involved in the disease empowered targeted research aimed toward early intervention in the epileptogenicity process. In this review, we present an update on the pharmacological treatments in tuberous sclerosis-related epilepsy.

Current concepts on epilepsy management in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous disease affecting approximately 1 in 6,000 people, and represents one of the most common genetic causes of epilepsy. Epilepsy affects 90% of the patients and appears in the first 2 years of life in the majority of them. Early onset of epilepsy in the first 12 months of life is associated with high risk of cognitive decline and neuropsychiatric problems including autism. Prenatal or early infantile diagnosis of TSC, before the onset of epilepsy, provides a unique opportunity to monitor EEG before the onset of clinical seizures, thus enabling early intervention in the process of epileptogenesis. In this review, we discuss the current status of knowledge on epileptogenesis in TSC, and present recommendations of American and European experts in the field of epilepsy.

Ketogenic diet: Predictors of seizure control

BACKGROUND

The ketogenic diet is an effective non-pharmacologic treatment for medically resistant epilepsy. The aim of this study was to identify any predictors that may influence the response of ketogenic diet.

METHODS

A retrospective chart review for all patients with medically resistant epilepsy was performed at a tertiary care epilepsy center from 1996 to 2012. Patient- and diet-related variables were evaluated with respect to seizure reduction at 1, 3, 6, 9 and 12-month intervals and divided into four possible outcome classes.

RESULTS

Sixty-three patients met inclusion. Thirty-seven (59%) reported >50% seizure reduction at 3 months with 44% and 37% patients benefiting at 6-month and 12-month follow up, respectively. A trend toward significant seizure improvement was noted in 48% patients with seizure onset >1 year at 12-month (p = 0.09) interval and in 62% patients with >10 seizure/day at 6-month interval (p = 0.054). An ordinal logistic regression showed later age of seizure to have higher odds of favorable response at 1-month (p = 0.005) and 3-month (p = 0.013) follow up. Patients with non-fasting diet induction were more likely to have a favorable outcome at 6 months (p = 0.008) as do females (p = 0.037) and those treated with higher fat ratio diet (p = 0.034).

CONCLUSION

Our study reports the effectiveness of ketogenic diet in children with medically resistant epilepsy. Later age of seizure onset, female gender, higher ketogenic diet ratio and non-fasting induction were associated with better odds of improved seizure outcome. A larger cohort is required to confirm these findings.

Time-frequency analysis of intracranial EEG in patients with myoclonic seizures

Myoclonic seizures are defined as generalized seizures according to the classification of seizure by the International League Against Epilepsy (ILAE). The pathogenesis of myoclonic seizures is not yet clear. There are very few studies on the focal surgical treatment of myoclonic seizures. The aim of this study is to investigate the characteristics of myoclonic seizure onset in different bands of the intracranial electroencephalogram (EEG) and their dynamic changes in temporal and spatial evolution. We studied four patients with myoclonic seizures who were under the focal resection of the epileptogenic zone. We retrospectively analyzed the semiology, electrocorticogram (ECoG) and imaging data of these patients, and conducted time-frequency analysis of broadband ECoG activity. We found that myoclonic seizures without clinical lateralizing signs could be improved by the resection of the epileptogenic zone. The ECoG power in different frequency bands increased to a peak at 0.5s before the clinical seizure onset and decreased quickly afterwards. The power of alpha activity was highest during the preictal and ictal periods. The central zone had higher power than the epileptogenic zone in all frequency bands during the preictal period, but this difference was not statistically significant. Our results suggest that myoclonic seizures in some patients might have a focal origination, with a fast bilateral propagating network in all frequency bands, especially the alpha band.

The ketogenic diet in pharmacoresistant childhood epilepsy

Available pharmacologic treatments for seizures are limited in their efficacy. For a patient with seizures, pharmacologic treatment with available anticonvulsant medications leads to seizure control in <70% of patients. Surgical resection can lead to control in a select subset of patients but still leaves a significant number of patients with uncontrolled seizures. The ketogenic diet and related diets have proven to be useful in pharmacoresistant childhood epilepsy.

The neuropathology of obesity: insights from human disease

Obesity, a pathologic state defined by excess adipose tissue, is a significant public health problem as it affects a large proportion of individuals and is linked with increased risk for numerous chronic diseases. Obesity is the result of fundamental changes associated with modern society including overnutrition and sedentary lifestyles. Proper energy homeostasis is dependent on normal brain function as the master metabolic regulator, which integrates peripheral signals, modulates autonomic outflow and controls feeding behavior. Therefore, many human brain diseases are associated with obesity. This review explores the neuropathology of obesity by examining brain diseases which either cause or are influenced by obesity. First, several genetic and acquired brain diseases are discussed as a means to understand the central regulation of peripheral metabolism. These diseases range from monogenetic causes of obesity (leptin deficiency, MC4R deficiency, Bardet-Biedl syndrome and others) to complex neurodevelopmental disorders (Prader-Willi syndrome and Sim1 deficiency) and neurodegenerative conditions (frontotemporal dementia and Gourmand's syndrome) and serve to highlight the central regulatory mechanisms which have evolved to maintain energy homeostasis. Next, to examine the effect of obesity on the brain, chronic neuropathologic conditions (epilepsy, multiple sclerosis and Alzheimer's disease) are discussed as examples of obesity leading to maladaptive processes which exacerbate chronic disease. Thus, obesity is associated with multiple pathways including abnormal metabolism, altered hormonal signaling and increased inflammation which act in concert to promote downstream neuropathology. Finally, the effect of anti-obesity interventions is discussed in terms of brain structure and function. Together, understanding human diseases and anti-obesity interventions leads to insights into the bidirectional interaction between peripheral metabolism and central brain function, highlighting the need for continued clinicopathologic and mechanistic studies of the neuropathology of obesity.

Harnessing the power of metabolism for seizure prevention: focus on dietary treatments

The continued occurrence of refractory seizures in at least one-third of children and adults with epilepsy, despite the availability of almost 15 conventional and novel anticonvulsant drugs, speaks to a dire need to develop novel therapeutic approaches. Cellular metabolism, the critical pathway by which cells access and utilize energy, is essential for normal neuronal function. Furthermore, mounting evidence suggests direct links between energy metabolism and cellular excitability. The high-fat, low-carbohydrate ketogenic diet has been used as a treatment for drug-refractory epilepsy for almost a century. Yet, the multitude of alternative therapies to target aspects of cellular metabolism and hyperexcitability is almost untapped. Approaches discussed in this review offer a wide diversity of therapeutic targets that might be exploited by investigators in the search for safer and more effective epilepsy treatments.

The ketogenic diet 2011: how it works

Although the ketogenic diet (KD) has been widely accepted as a legitimate and successful therapy for epilepsy and other neurological disorders, its mechanism of action remains an enigma. The use of the KD causes major metabolic changes. The most significant of them seems to be the situation of chronic ketosis, but there are others as well, for instance, high level of polyunsaturated fatty acids (PUFAs). These “primary” influences lead to “secondary”, in part adaptive, effects, for instance changes in mitochondrial density and gene expression. Clinically, the influences of the diet are considered as anticonvulsive and neuroprotective, although neuroprotection can also lead to prevention of seizures. Potential clinical implications of these mechanisms are discussed.

Monocarboxylate transporter 1 is deficient on microvessels in the human epileptogenic hippocampus

Monocarboxylate transporter 1 (MCT1) facilitates the transport of important metabolic fuels (lactate, pyruvate and ketone bodies) and possibly also acidic drugs such as valproic acid across the blood-brain barrier. Because an impaired brain energy metabolism and resistance to antiepileptic drugs are common features of temporal lobe epilepsy (TLE), we sought to study the expression of MCT1 in the brain of patients with this disease. Immunohistochemistry and immunogold electron microscopy were used to assess the distribution of MCT1 in brain specimens from patients with TLE and concomitant hippocampal sclerosis (referred to as mesial TLE or MTLE (n=15)), patients with TLE and no hippocampal sclerosis (non-MTLE, n=13) and neurologically normal autopsy subjects (n=8). MCT1 was present on an extensive network of microvessels throughout the hippocampal formation in autopsy controls and to a lesser degree in non-MTLE. Patients with MTLE were markedly deficient in MCT1 on microvessels in several areas of the hippocampal formation, especially CA1, which exhibited a 37% to 48% loss of MCT1 on the plasma membrane of endothelial cells when compared with non-MTLE. These findings suggest that the uptake of blood-derived monocarboxylate fuels and possibly also acidic drugs, such as valproic acid, is perturbed in the epileptogenic hippocampus, particularly in MTLE. We hypothesize that the loss of MCT1 on brain microvessels is mechanistically involved in the pathophysiology of drug-resistant TLE, and propose that re-expression of MCT1 may represent a novel therapeutic approach for this disease.

Treatment of Lennox-Gastaut Syndrome (LGS)

Lennox-Gastaut Syndrome (LGS) is a severe form of epilepsy that usually starts in early to mid childhood and is characterized by multiple seizure types, abnormal electroencephalogram with slow spike-and-wave discharges and cognitive problems. Numerous approaches are currently used to treat LGS, including use of conventional antiepileptic drugs (most commonly sodium valproate, lamotrigine and topiramate), other drug interventions (corticosteroids and intravenous immunoglobulin) and nonpharmacologic treatments (ketogenic diet, corpus callosotomy and vagus nerve stimulation). Rufinamide is the most recent antiepileptic drug to have shown efficacy in the treatment of LGS. Despite the variety of therapeutic options, there have been only five double-blind, placebo-controlled clinical trials of antiepileptic drugs in LGS and none of these were head-to-head comparison trials. The evidence supporting the use of available treatments for LGS is, therefore, not robust. Here, we review the evidence supporting the use of specific therapies in LGS and provide recommendations on how to set appropriate treatment goals, select treatments and minimize polypharmacy. A suggested treatment algorithm is presented and discussed. Sodium valproate is recommended for first-line therapy; if seizures persist, alternative interventions should be trialed on an individually tailored basis.