Danger in the pipeline for the ketogenic diet?

Neuro-Behavioral Status and the Hippocampal Expression of Metabolic Associated Genes in Wild-Type Rat Following a Ketogenic Diet

While a ketogenic diet (KD) is a well-established therapy for medically intractable epilepsy, clinical evidence of relevant adverse events of a KD has also been reported. We asked whether this kind of diet would have deleterious effects on wild-type brain function by evaluating KD-induced biochemical changes in the hippocampus as well as neurobehavioral changes occurring in wild-type rats. Fifty-four Sprague-Dawley rats were randomly assigned to three groups on postnatal day 28 (P28): wild-type rats fed with a KD qd (daily for 4 weeks, KD) or qod (every other day for 4 weeks, KOD), and wild-type rats fed with standard normal laboratory diet (ND). Neurobehavioral changes were observed on P35, P42, and P49. The hippocampal mossy fiber sprouting, the expression levels of zinc transporters (ZnTs) and lipid metabolism related genes were detected by Timm staining, RT-qPCR and western blot analysis, respectively, on P58. The KD-treated KOD and KD groups showed a significant delay of negative geotaxis reflex on P35, but not on P42 or P49. In the open field test, daily KD treatment only led to a reduction in exploratory activity and increased grooming times but induced no significant changes in the scores of vertical activity or delay time. KD qod treated rats (KOD) displayed a slight delay in the place navigation test on P35 compared with the KD group. There were no significant differences in Timm staining among the three groups. In parallel with these changes, KD treatment (both KD and KOD) induced significantly downregulated mRNA levels of Apoa1, Pdk4, and upregulated expression of ApoE, ANXN7, and cPLA2 in the hippocampus when compared with the ND group (except in the case of ApoE in the KOD group). Notably, both the mRNA and protein levels of cPLA2 in the KOD rats were significantly downregulated compared with the KD group but still markedly higher than in the ND group. No significant difference was found in ZnTs among the three groups. Our data suggest that early-life KD can provoke minor neurobehavioral effects in particular a delay in negative geotaxis reflex and an increase in grooming activity. The hippocampal lipid metabolism signaling pathway, especially cPLA2, may be the target of the protective effect of KD on long-term brain injury after developmental seizures.

The Current Status of the Ketogenic Diet in Psychiatry

BACKGROUND

The ketogenic diet (KD) has been used in treatment-resistant epilepsy since the 1920s. It has been researched in a variety of neurological conditions in both animal models and human trials. The aim of this review is to clarify the potential role of KD in psychiatry.

METHODS

Narrative review of electronic databases PubMED, PsychINFO, and Scopus.

RESULTS

The search yielded 15 studies that related the use of KD in mental disorders including anxiety, depression, bipolar disorder, schizophrenia, autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD). These studies comprised nine animal models, four case studies, and two open-label studies in humans. In anxiety, exogenous ketone supplementation reduced anxiety-related behaviors in a rat model. In depression, KD significantly reduced depression-like behaviors in rat and mice models in two controlled studies. In bipolar disorder, one case study reported a reduction in symptomatology, while a second case study reported no improvement. In schizophrenia, an open-label study in female patients (n = 10) reported reduced symptoms after 2 weeks of KD, a single case study reported no improvement. In a brief report, 3 weeks of KD in a mouse model normalized pathological behaviors. In ASD, an open-label study in children (n = 30) reported no significant improvement; one case study reported a pronounced and sustained response to KD. In ASD, in four controlled animal studies, KD significantly reduced ASD-related behaviors in mice and rats. In ADHD, in one controlled trial of KD in dogs with comorbid epilepsy, both conditions significantly improved.

CONCLUSION

Despite its long history in neurology, the role of KD in mental disorders is unclear. Half of the published studies are based on animal models of mental disorders with limited generalizability to the analog conditions in humans. The review lists some major limitations including the lack of measuring ketone levels in four studies and the issue of compliance to the rigid diet in humans. Currently, there is insufficient evidence for the use of KD in mental disorders, and it is not a recommended treatment option. Future research should include long-term, prospective, randomized, placebo-controlled crossover dietary trials to examine the effect of KD in various mental disorders.

Ketogenic diet change cPLA2/clusterin and autophagy related gene expression and correlate with cognitive deficits and hippocampal MFs sprouting following neonatal seizures

Because the ketogenic diet (KD) was affecting expression of energy metabolism- related genes in hippocampus and because lipid membrane peroxidation and its associated autophagy stress were also found to be involved in energy depletion, we hypothesized that KD might exert its neuroprotective action via lipid membrane peroxidation and autophagic signaling. Here, we tested this hypothesis by examining the long-term expression of lipid membrane peroxidation-related cPLA2 and clusterin, its downstream autophagy marker Beclin-1, LC3 and p62, as well as its execution molecule Cathepsin-E following neonatal seizures and chronic KD treatment. On postnatal day 9 (P9), 48 Sprague-Dawley rats were randomly assigned to two groups: flurothyl-induced recurrent seizures group and control group. On P28, they were further randomly divided into the seizure group without ketogenic diet (RS+ND), seizure plus ketogenic diet (RS+KD), the control group without ketogenic diet (NS+ND), and the control plus ketogenic diet (NS+KD). Morris water maze test was performed during P37-P43. Then mossy fiber sprouting and the protein levels were detected by Timm staining and Western blot analysis, respectively. Flurothyl-induced RS+ND rats show a long-term lower amount of cPLA2 and LC3II/I, and higher amount of clusterin, Beclin-1, p62 and Cathepsin-E which are in parallel with hippocampal mossy fiber sprouting and cognitive deficits. Furthermore, chronic KD treatment (RS+KD) is effective in restoring these molecular, neuropathological and cognitive changes. The results imply that a lipid membrane peroxidation and autophagy-associated pathway is involved in the aberrant hippocampal mossy fiber sprouting and cognitive deficits following neonatal seizures, which might be a potential target of KD for the treatment of neonatal seizure-induced brain damage.

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.