Early Motor-Behavioral Outcome of Ischemic Stroke with Ketogenic Diet Preconditioning: Interventional Animal Study

Remote Ischemic Postconditioning-Mediated Neuroprotection against Stroke by Promoting Ketone Body-Induced Ferroptosis Inhibition

Neuronal death resulting from ischemic stroke is the primary cause of adult mortality and disability, and effective neuroprotective agents for poststroke intervention are still lacking. Remote ischemic postconditioning (RIPostC) has demonstrated significant protective effects against ischemia in various organs; however, the specific mechanisms are not fully understood. This study investigated the potential neuroprotective mechanisms of RIPostC in the context of ischemic stroke. Using a rat model of middle cerebral artery occlusion, we found that RIPostC mitigated neurological damage, improved movement in the open-field test, and protected against neuronal apoptosis. In terms of energy metabolism, RIPostC enhanced ATP levels, suppressed lactate content, and increased the production of ketone bodies (KBs). In the ferroptosis assay, RIPostC protected against lipoperoxidation, reversed the reduction of glutathione peroxidase 4 (GPX4), and mitigated the excessive expression of long-chain acyl-CoA synthetase family member 4 (ACSL4). In oxygen-glucose deprivation/reoxygenation-treated HT22 cells, KBs maintained GPX4 levels, suppressed ACSL4 expression, and preserved the mitochondrial cristae number. However, the effect of KBs on the expression of GPX4, ACSL4, and the number of mitochondrial cristae was blocked by erastin. Moreover, both RIPostC and KBs reduced total iron and ferrous ion content by repressing iron transporters both in vitro and in vivo. In conclusion, KBs-induced mitigation of ferroptosis could represent a new therapeutic mechanism for RIPostC in treating stroke.

Molecular Mechanisms of Neuroprotection by Ketone Bodies and Ketogenic Diet in Cerebral Ischemia and Neurodegenerative Diseases

Ketone bodies (KBs), such as acetoacetate and β-hydroxybutyrate, serve as crucial alternative energy sources during glucose deficiency. KBs, generated through ketogenesis in the liver, are metabolized into acetyl-CoA in extrahepatic tissues, entering the tricarboxylic acid cycle and electron transport chain for ATP production. Reduced glucose metabolism and mitochondrial dysfunction correlate with increased neuronal death and brain damage during cerebral ischemia and neurodegeneration. Both KBs and the ketogenic diet (KD) demonstrate neuroprotective effects by orchestrating various cellular processes through metabolic and signaling functions. They enhance mitochondrial function, mitigate oxidative stress and apoptosis, and regulate epigenetic and post-translational modifications of histones and non-histone proteins. Additionally, KBs and KD contribute to reducing neuroinflammation and modulating autophagy, neurotransmission systems, and gut microbiome. This review aims to explore the current understanding of the molecular mechanisms underpinning the neuroprotective effects of KBs and KD against brain damage in cerebral ischemia and neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease.

Ketogenic diet protects MPTP-induced mouse model of Parkinson's disease via altering gut microbiota and metabolites

The ketogenic diet (KD) is a low-carbohydrate, high-fat regime that is protective against neurodegenerative diseases. However, the impact of KD on Parkinson's disease (PD) and its mechanisms remains unclear. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD was fed with KD for 8 weeks. Motor function and dopaminergic neurons were evaluated. Inflammation in the brain, plasma, and colon tissue were also measured. Fecal samples were assessed by 16S rDNA gene sequencing and untargeted metabolomics. We found that KD protected motor dysfunction, dopaminergic neuron loss, and inflammation in an MPTP mouse model of PD. 16S rDNA sequencing revealed that MPTP administration significantly increased Citrobacter, Desulfovibrio, and Ruminococcus, and decreased Dubosiella, whereas KD treatment reversed the dysbiosis. Meanwhile, KD regulated the MPTP-induced histamine, N-acetylputrescine, d-aspartic acid, and other metabolites. Fecal microbiota transplantation using feces from the KD-treated mice attenuated the motor function impairment and dopaminergic neuron loss in antibiotic-pretreated PD mice. Our current study demonstrates that KD played a neuroprotective role in the MPTP mouse model of PD through the diet-gut microbiota-brain axis, which may involve inflammation in the brain and colon. However, future research is warranted to explore the explicit anti-inflammatory mechanisms of the gut-brain axis in PD models fed with KD.

Ketogenic Diet and Ketone Bodies against Ischemic Injury: Targets, Mechanisms, and Therapeutic Potential

The ketogenic diet (KD) has been used as a treatment for epilepsy since the 1920s, and its role in the prevention of many other diseases is now being considered. In recent years, there has been an intensive investigation on using the KD as a therapeutic approach to treat acute pathologies, including ischemic ones. However, contradictory data are observed for the effects of the KD on various organs after ischemic injury. In this review, we provide the first systematic analysis of studies conducted from 1980 to 2022 investigating the effects and main mechanisms of the KD and its mimetics on ischemia-reperfusion injury of the brain, heart, kidneys, liver, gut, and eyes. Our analysis demonstrated a high diversity of both the composition of the used KD and the protocols for the treatment of animals, which could be the reason for contradictory effects in different studies. It can be concluded that a true KD or its mimetics, such as β-hydroxybutyrate, can be considered as positive exposure, protecting the organ from ischemia and its negative consequences, whereas the shift to a rather similar high-calorie or high-fat diet leads to the opposite effect.

Bibliometric analysis of global research profile on ketogenic diet therapies in neurological diseases: Beneficial diet therapies deserve more attention

Background

The protective effects of Ketogenic Diet Therapies (KDTs) on neurological diseases have been extensively studied over the past two decades. The purpose of this study was to quantitatively and qualitatively analyze the publication of KDTs in the neurological field from 2000 to 2021.

Methods

A literature search was performed on June 7th, 2022, using the search terms: (("ketone" OR "ketogenic" OR "*hydroxybuty*") AND ("neuro*")) in the WoSCC database. Collected data were further analyzed using VOSviewer, CiteSpace and other online bibliometric websites. The annual publication volume and citation trends were summarized. The collaborations among highly cited countries, institutions, authors and journals were visualized. The co-citation analysis of highly cited references and journals were also visualized. Moreover, the research focuses and fronts were revealed by co-occurrence analysis and burst keywords detection.

Results

A total of 2808 publications with 88,119 citations were identified. From 2000-2021, the number of publications and citations presented rising trends. The United States was the country with an overwhelming number of publications and cited times. Johns Hopkins University was the most contributory institution. Kossoff Eric H was the author with the largest number of publications. And Epilepsia was both the largest publisher and the most frequently cited journal. The keywords of intense interest involved "Modified Atkins Diet", "Temporal Lobe Epilepsy", "Alzheimer's Disease", "Parkinson's Disease", "Cerebral Blood Flow", "Neuroinflammation", "Oxidative Stress", "Metabolism" and "Mitochondria".

Conclusion

We presented the global trend of KDTs in neurological diseases and provided important information for relevant researchers in a bibliometric way. This bibliometric study revealed that treating epilepsy, neuroprotection and functional effects of KDTs on mitochondria and oxidative stress have been the spotlight from 2000 to 2021. These have emerged as the basis for transformation from basic research to clinical application of KDTs.

Establishment of longitudinal transcranial stimulation motor evoked potentials monitoring of the forelimbs and hindlimbs in an ischemic stroke rat model

Evaluation of motor function ischemic stroke rat models includes qualitative assessments such as the modified neurological severity score (mNSS). However, mNSS cannot evaluate the function of forelimbs and hindlimbs separately. We quantitatively assessed motor function in a middle cerebral artery occlusion (MCAO) rat model of ischemic stroke. We recorded transcranial stimulation motor evoked potentials (tcMEPs) from MCAO rats and measured the changes in onset latency and amplitude at the forelimbs and hindlimbs up to 28 days after stroke. All MCAO subjects showed hemiparesis. The amplitudes of tcMEPs in both fore- and hindlimbs were inversely correlated with mNSS scores, but the amplitudes in the forelimbs improved later than those in the hindlimbs. The onset latency of tcMEPs in the forelimbs and hindlimbs remained almost unchanged during the follow-up period. Our results showed the differences in tcMEPs amplitude recovery times between the forelimbs and hindlimbs after MCAO, which emphasizes the importance of separately evaluating forelimbs and hindlimbs in post-ischemic stroke models. This minimally invasive and longitudinal quantitative method could be useful for further research on diseases and neurogenesis.

Gut microbes in cerebrovascular diseases: Gut flora imbalance, potential impact mechanisms and promising treatment strategies

The high morbidity, mortality, and disability rates associated with cerebrovascular disease (CeVD) pose a severe danger to human health. Gut bacteria significantly affect the onset, progression, and prognosis of CeVD. Gut microbes play a critical role in gut-brain interactions, and the gut-brain axis is essential for communication in CeVD. The reflection of changes in the gut and brain caused by gut bacteria makes it possible to investigate early warning biomarkers and potential treatment targets. We primarily discussed the following three levels of brain-gut interactions in a systematic review of the connections between gut microbiota and several cerebrovascular conditions, including ischemic stroke, intracerebral hemorrhage, intracranial aneurysm, cerebral small vessel disease, and cerebral cavernous hemangioma. First, we studied the gut microbes in conjunction with CeVD and examined alterations in the core microbiota. This enabled us to identify the focus of gut microbes and determine the focus for CeVD prevention and treatment. Second, we discussed the pathological mechanisms underlying the involvement of gut microbes in CeVD occurrence and development, including immune-mediated inflammatory responses, variations in intestinal barrier function, and reciprocal effects of microbial metabolites. Finally, based on the aforementioned proven mechanisms, we assessed the effectiveness and potential applications of the current therapies, such as dietary intervention, fecal bacterial transplantation, traditional Chinese medicine, and antibiotic therapy.

Diet-microbiome-gut-brain nexus in acute and chronic brain injury

In recent years, appreciation for the gut microbiome and its relationship to human health has emerged as a facilitator of maintaining healthy physiology and a contributor to numerous human diseases. The contribution of the microbiome in modulating the gut-brain axis has gained significant attention in recent years, extensively studied in chronic brain injuries such as Epilepsy and Alzheimer’s Disease. Furthermore, there is growing evidence that gut microbiome also contributes to acute brain injuries like stroke(s) and traumatic brain injury. Microbiome-gut-brain communications are bidirectional and involve metabolite production and modulation of immune and neuronal functions. The microbiome plays two distinct roles: it beneficially modulates immune system and neuronal functions; however, abnormalities in the host’s microbiome also exacerbates neuronal damage or delays the recovery from acute injuries. After brain injury, several inflammatory changes, such as the necrosis and apoptosis of neuronal tissue, propagates downward inflammatory signals to disrupt the microbiome homeostasis; however, microbiome dysbiosis impacts the upward signaling to the brain and interferes with recovery in neuronal functions and brain health. Diet is a superlative modulator of microbiome and is known to impact the gut-brain axis, including its influence on acute and neuronal injuries. In this review, we discussed the differential microbiome changes in both acute and chronic brain injuries, as well as the therapeutic importance of modulation by diets and probiotics. We emphasize the mechanistic studies based on animal models and their translational or clinical relationship by reviewing human studies.

Nutritional Impact on Metabolic Homeostasis and Brain Health

Aging in modern societies is often associated with various diseases including metabolic and neurodegenerative disorders. In recent years, researchers have shown that both dysfunctions are related to each other. Although the relationship is not fully understood, recent evidence indicate that metabolic control plays a determinant role in neural defects onset. Indeed, energy balance dysregulation affects neuroenergetics by altering energy supply and thus neuronal activity. Consistently, different diets to help control body weight, blood glucose or insulin sensitivity are also effective in improving neurodegenerative disorders, dampening symptoms, or decreasing the risk of disease onset. Moreover, adapted nutritional recommendations improve learning, memory, and mood in healthy subjects as well. Interestingly, adjusted carbohydrate content of meals is the most efficient for both brain function and metabolic regulation improvement. Notably, documented neurological disorders impacted by specific diets suggest that the processes involved are inflammation, mitochondrial function and redox balance as well as ATP production. Interestingly, processes involving inflammation, mitochondrial function and redox balance as well as ATP production are also described in brain regulation of energy homeostasis. Therefore, it is likely that changes in brain function induced by diets can affect brain control of energy homeostasis and other brain functions such as memory, anxiety, social behavior, or motor skills. Moreover, a defect in energy supply could participate to the development of neurodegenerative disorders. Among the possible processes involved, the role of ketone bodies metabolism, neurogenesis and synaptic plasticity, oxidative stress and inflammation or epigenetic regulations as well as gut-brain axis and SCFA have been proposed in the literature. Therefore, the goal of this review is to provide hints about how nutritional studies could help to better understand the tight relationship between metabolic balance, brain activity and aging. Altogether, diets that help maintaining a metabolic balance could be key to both maintain energy homeostasis and prevent neurological disorders, thus contributing to promote healthy aging.

Ketone Supplementation: Meeting the Needs of the Brain in an Energy Crisis

Diverse neurological disorders are associated with a deficit in brain energy metabolism, often characterized by acute or chronic glucose hypometabolism. Ketones serve as the brain's only significant alternative fuel and can even become the primary fuel in conditions of limited glucose availability. Thus, dietary supplementation with exogenous ketones represents a promising novel therapeutic strategy to help meet the energetic needs of the brain in an energy crisis. Preliminary evidence suggests ketosis induced by exogenous ketones may attenuate damage or improve cognitive and motor performance in neurological conditions such as seizure disorders, mild cognitive impairment, Alzheimer's disease, and neurotrauma.

Neuroprotection by the Ketogenic Diet: Evidence and Controversies

The ketogenic diet (KD) is a high-fat low-carbohydrate diet that has been used for decades as a non-pharmacologic approach to treat metabolic disorders and refractory pediatric epilepsy. In recent years, enthusiasm for the KD has increased in the scientific community due to evidence that the diet reduces pathology and improves various outcome measures in animal models of neurodegenerative disorders, including multiple sclerosis, stroke, glaucoma, spinal cord injury, retinal degenerations, Parkinson's disease and Alzheimer's disease. Clinical trials also suggest that the KD improved quality of life in patients with multiple sclerosis and Alzheimer's disease. Furthermore, the major ketone bodies BHB and ACA have potential neuroprotective properties and are now known to have direct effects on specific inflammatory proteins, transcription factors, reactive oxygen species, mitochondria, epigenetic modifications and the composition of the gut microbiome. Neuroprotective benefits of the KD are likely due to a combination of these cellular processes and other potential mechanisms that are yet to be confirmed experimentally. This review provides a comprehensive summary of current evidence for the effectiveness of the KD in humans and preclinical models of various neurological disorders, describes molecular mechanisms that may contribute to its beneficial effects, and highlights key controversies and current gaps in knowledge.

Emerging Role of the Ketogenic Dietary Therapies beyond Epilepsy in Child Neurology

Ketogenic dietary therapies (KDTs) have been in use for refractory paediatric epilepsy for a century now. Over time, KDTs themselves have undergone various modifications to improve tolerability and clinical feasibility, including the Modified Atkins diet (MAD), medium chain triglyceride (MCT) diet and the low glycaemic index treatment (LGIT). Animal and observational studies indicate numerous benefits of KDTs in paediatric neurological conditions apart from their evident benefits in childhood intractable epilepsy, including neurodevelopmental disorders such as autism spectrum disorder, rarer neurogenetic conditions such as Rett syndrome, Fragile X syndrome and Kabuki syndrome, neurodegenerative conditions such as Pelizaeus-Merzbacher disease, and other conditions such as stroke and migraine. A large proportion of the evidence is derived from individual case reports, case series and some small clinical trials, emphasising the vast scope for research in this avenue. The term 'neuroketotherapeutics' has been coined recently to encompass the rapid strides in this field. In the 100^th year of its use for paediatric epilepsy, this review covers the role of the KDTs in non-epilepsy neurological conditions among children.

Intermittent fasting in paediatric critical illness: The properties and potential beneficial effects of an overnight fast in the PICU

Although evidence for the superiority of continuous feeding over intermittent feeding is lacking, in most paediatric intensive care units (PICU) artificial feeding is administered continuously for 24 h per day. Until now, studies in PICU on intermittent feeding have primarily focused on surrogate endpoints such as nutritional intake and gastro-intestinal complaints and none have studied the effects of an extended fasting period. Intermittent fasting has been proven to have many health benefits in both animal and human studies. The observed beneficial effects are based on multiple metabolic and endocrine changes that are presumed crucial in critical illness as well. One key element is the transition to ketone body metabolism, which, among others, contributes to the stimulation of several cellular pathways involved in stress resistance (neuro)plasticity and mitochondrial biogenesis, and might help preserve brain function. Secondly, the fasting state stimulates the activation of autophagy, a process that is crucial for cellular function and integrity. Of the different intermittent fasting strategies investigated, time-restricted feeding with a daily extended fasting period appears most feasible in the PICU. Moreover, planning the fasting period overnight could help maintain the circadian rhythm. Although not investigated, such an overnight intermittent fasting strategy might improve the metabolic profile, feeding tolerance and perhaps even have beneficial effects on tissue repair, reperfusion injury, muscle weakness, and the immune response. Future studies should investigate practical implications in critically ill children and the optimal duration of the fasting periods, which might be affected by the severity of illness and by age.

The relation of etiology based on the 2017 ILAE classification to the effectiveness of the ketogenic diet in drug-resistant epilepsy in childhood

Objective

To investigate the effectiveness and safety of the ketogenic diet (KD) in drug‐resistant epilepsy in childhood in relation to the new 2017 International League Against Epilepsy (ILAE) classification of etiology.

Methods

A consecutive cohort of patients treated with the KD were categorized according to the ILAE classification into known (structural, genetic, metabolic, infectious, and immune‐mediated) and unknown etiology. Primary outcome was the frequency of patients achieving seizure freedom with the KD at 3 months, secondary outcomes were seizure reduction >50% at 3 months, and both seizure freedom and seizure reduction >50% at 6, 12 months, and at last follow‐up (LFU), and adverse effects. Outcomes were compared between etiology groups.

Results

Etiology was known in 70% (129/183). Outcomes did not differ at 3 months (known vs unknown: seizure freedom 28% vs 33%, seizure reduction 62 vs 67%), but seizure freedom was significantly less frequent in known etiology at 6 months (26% vs 43%) and beyond (22% vs 37%). Logistic regression identified duration of epilepsy, number of previous antiseizure medications (ASMs), and age‐appropriate psychomotor development as positive determinants of outcome. Among individual etiology groups, the effectiveness of KD was relatively best for genetic (33% at LFU) and poorest for metabolic etiology (8% at LFU). The small number of patients with infectious and immune‐mediated etiology requires larger numbers in each etiology group to corroborate our results. No differences in type and frequency of adverse effects (in 71%) between etiology groups were observed, requiring medical intervention in 21%.

Significance

The KD was most effective in genetic and unknown etiology, many unknowns probably represent yet unidentified genetic causes. We recommend consequent diagnostic and genetic work‐up to identify etiologies that respond best to the KD. The KD should be offered early to infants with genetic epilepsy before deterioration of epileptic symptoms and of psychomotor development.

Nutritional Supplements and Neuroprotective Diets and Their Potential Clinical Significance in Post-Stroke Rehabilitation

Nutrition and rehabilitation are crucial in post-stroke recovery, especially in the elderly. Since stroke is the leading cause of long-term disability, there is a need to promote special, individually tailored nutrition strategies targeting older patients with low motor ability. Chronic stroke survivors have higher risk of developing nutrition-related chronic diseases, such as sarcopenia, anemia, type 2 diabetes mellitus and osteoporosis. Moreover, reduced motor activity, cognitive impairment and depression might be aggravated by poor malnutrition status. Accumulated data suggest that nutritional supplements and neuroprotective diets can be associated with better effectiveness of post-stroke rehabilitation as well as brain recovery. Therefore, this review focuses on preventive strategies that can improve dietary intake and change dietary patterns. We highlight the importance of neuroprotective diets, the problem of dysphagia and the role of nutrition in rehabilitation. This article focuses on potential nutritional supplements and neuroprotective diets that may have an impact on functional recovery during and after rehabilitation. Moreover, a new approach to post-stroke neuroplasticity including the use of agents from marine sources such as fucoxanthin and tramiprosate as compounds that might be used as potential neuroprotectants with antioxidative and anti-inflammatory properties is introduced.

Ketogenic diet-mediated steroid metabolism reprogramming improves the immune microenvironment and myelin growth in spinal cord injury rats according to gene and co-expression network analyses

The ketogenic diet has been widely used in the treatment of various nervous system and metabolic-related diseases. Our previous research found that a ketogenic diet exerts a protective effect and promotes functional recovery after spinal cord injury. However, the mechanism of action is still unclear. In this study, different dietary feeding methods were used, and myelin expression and gene level changes were detected among different groups. We established 15 RNA-seq cDNA libraries from among 4 different groups. First, KEGG pathway enrichment of upregulated differentially expressed genes and gene set enrichment analysis of the ketogenic diet and normal diet groups indicated that a ketogenic diet significantly improved the steroid anabolic pathway in rats with spinal cord injury. Through cluster analysis, protein-protein interaction analysis and visualization of iPath metabolic pathways, it was determined that Sqle, Sc5d, Cyp51, Dhcr24, Msmo1, Hsd17b7, and Fdft1 expression changed significantly. Second, through weighted gene co-expression network analysis showed that rats fed a ketogenic diet showed a significant reduction in the expression of genes involved in immune-related pathways, including those associated with immunity and infectious diseases. A ketogenic diet may improve the immune microenvironment and myelin growth in rats with spinal cord injury through reprogramming of steroid metabolism.

Alterations in the gut microbiota and metabolite profiles in the context of neuropathic pain

The aim of this study was to explore the relationships among gut microbiota disturbances and serum and spinal cord metabolic disorders in neuropathic pain. 16S rDNA amplicon sequencing and serum and spinal cord metabolomics were used to identify alterations in the microbiota and metabolite profiles in the sham rats and the chronic constriction injury (CCI) model rats. Correlations between the abundances of gut microbiota components at the genus level, the levels of serum metabolites, and pain-related behavioural parameters were analysed. Ingenuity pathway analysis (IPA) was applied to analyse the interaction networks of the differentially expressed serum metabolites. First, we found that the composition of the gut microbiota was different between rats with CCI-induced neuropathic pain and sham controls. At the genus level, the abundances of Helicobacter, Phascolarctobacterium, Christensenella, Blautia, Streptococcus, Rothia and Lactobacillus were significantly increased, whereas the abundances of Ignatzschineria, Butyricimonas, Escherichia, AF12, and Corynebacterium were significantly decreased. Additionally, 72 significantly differentially expressed serum metabolites and 17 significantly differentially expressed spinal cord metabolites were identified between the CCI rats and the sham rats. Finally, correlation analysis showed that changes in the gut microbiota was significantly correlated with changes in serum metabolite levels, suggesting that dysbiosis of the gut microbiota is an important factor in modulating metabolic disturbances in the context of neuropathic pain. In conclusion, our research provides a novel perspective on the potential roles of the gut microbiota and related metabolites in neuropathic pain.

Scientific evidence underlying contraindications to the ketogenic diet: An update

First identified as a feasible treatment for intractable epilepsy, the ketogenic diet (KD) has recently gained popularity thanks to growing evidence on applications such as weight loss, most importantly, but also NAFLD, cancer, neurologic conditions and chronic pain. As with any treatment, whether pharmacologic or not, the KD might not be an appropriate intervention for every individual, and a number of contraindications have been proposed, now deeply rooted into clinical practice, excluding de facto many patients that could benefit from its use. However, many of these concerns were expressed due to the absence of clinical studies conducted on fragile populations, and an assessment of lately emerged evidence relative to KD safety is currently lacking and much needed. We herein provide a critical revision of the literature behind each safety alert, in order to guide through the treatment options in the case of subjects with an indication to the KD and a borderline safe situation. Based on available evidence, the possible use of this diet as a therapeutic intervention should be assessed on a patient-to-patient basis by adequately skilled medical doctors, keeping in mind current recommendations, but reading them through the knowledge of the current state of the art.

Adenosine and Ketogenic Treatments

It is well known that the neuromodulator adenosine, acting through the adenosine A₁ receptor subtype, can limit or stop seizures. In 2008, adenosine was proposed as a key component of the anticonvulsant mechanism of the ketogenic diet (KD), a very low carbohydrate diet that can be highly effective in drug-refractory epilepsy. In this study, we review the accumulated data on the intersection among adenosine, ketosis, and anticonvulsant/antiepileptogenic effects. In several rodent models of epilepsy and seizures, antiseizure effects of ketogenic treatments (the KD itself, exogenous ketone bodies, medium-chain triglycerides or fatty acids) are reversed by administration of an adenosine A₁ receptor antagonist. In addition, KD treatment elevates extracellular adenosine and tissue adenosine content in brain. Efforts to maintain or mimic a ketogenic milieu in brain slices reveal a state of reduced excitability produced by pre- and postsynaptic adenosine A₁ receptor-based effects. Long-lasting seizure reduction may be due to adenosine-based epigenetic effects. In conclusion, there is accumulating evidence for an adenosinergic anticonvulsant action in the ketogenic state. In some cases, the main trigger is mildly but consistently lowered glucose in the brain. More research is needed to investigate the importance of adenosine in the antiepileptogenic and neuroprotective effects of these treatments. Future research may begin to investigate alternative adenosine-promoting strategies to enhance the KD or to find use as treatments themselves.

Application of ketogenic diets for pediatric neurocritical care

In this review, we summarize the general mechanisms of the ketogenic diet, and the application of a ketogenic diet in pediatric intensive care units for the neurological disorders of children and young infants. A ketogenic diet is a high-fat, low-carbohydrate, adequate-protein diet. It can alter the primary cerebral energy metabolism from glucose to ketone bodies, which involves multiple mechanisms of antiepileptic action, antiepileptogenic properties, neuro-protection, antioxidant and anti-inflammatory effects, and it is potentially a disease-modifying intervention. Although a ketogenic diet is typically used for the chronic stage of pharmacoresistant of epilepsy, recent studies have shown its efficacy in patients with the acute stage of refractory/super-refractory status epilepticus. The application of a ketogenic diet in pediatric intensive care units is a challenge because of the critical status of the patients, who are often in a coma or have a nothing by mouth order. Moreover, a ketogenic diet needs to be started early and sometimes through parenteral administration in patients with critical conditions such as refractory status epilepticus or febrile infection-related epilepsy syndrome. Animal models and some case reports have shown that the neuro-protective effects of a ketogenic diet can be extended to other emergent neurological diseases, such as traumatic brain injury and ischemic stroke.