Brain ketones detected by proton magnetic resonance spectroscopy in an infant with Ohtahara syndrome treated with ketogenic diet

Pharmacokinetic effects of a single-dose nutritional ketone ester supplement on brain ketone and glucose metabolism in alcohol use disorder - a pilot study

Introduction

Acute alcohol intake decreases brain glucose metabolism and increases brain uptake of acetate, a metabolite of alcohol. Individuals with alcohol use disorder (AUD) show elevated brain acetate metabolism at the expense of glucose, a shift in energy utilization that persists beyond acute intoxication. We recently reported that nutritional ketosis and administration of ketone bodies as an alternative energy source to glucose reduce alcohol withdrawal severity and alcohol craving in AUD. However, the regional effects of nutritional ketosis on brain ketone (beta-hydroxybutyrate [BHB]) and glucose metabolism have not been studied in AUD.

Methods

Five participants with AUD underwent two magnetic resonance imaging (MRI) sessions and 4 participants with AUD underwent two positron emission tomography (PET) sessions with 18 F-fluorodeoxyglucose. All participants completed one session without KE intervention and one session during which they consumed 395 mg/kg (R) -3-hydroxybutyl (R) -3-hydroxybutyrate Ketone Ester (KE) intervention (TdeltaS Global Inc.) before the scan. The order of the sessions was randomized. For the PET cohort, blood glucose and ketone levels were assessed and voxel-wise maps of the cerebral metabolic rate of glucose (CMRglc) were computed at each session. For the MRI cohort, brain anterior cingulate BHB levels were assessed using magnetic resonance spectroscopy.

Results

A single dose of KE elevated blood BHB and anterior cingulate BHB levels compared to baseline. Moreover, blood glucose levels were lower with KE than baseline, and whole-brain CMRglc decreased by 17%. The largest KE-induced CMRglc reductions were in the frontal, occipital, cortex, and anterior cingulate cortices.

Conclusion

These findings provide preliminary evidence that KE administration elevates ketone and reduces brain glucose metabolism in humans, consistent with a shift from glucose to ketones as a brain energy source. Average reductions in CMRglc of 17% are similar to global average reductions documented with administration of 0.25-0.5 g/kg of alcohol. Documenting the clinical and neurometabolic effects of nutritional ketosis will yield fundamental knowledge as to its potential beneficial effects as a treatment for AUD and its underlying neural mechanisms.

Clinical 1H MRS in childhood neurometabolic diseases-part 1: technique and age-related normal spectra

Despite its vigorous ability to detect and measure metabolic disturbances, ¹H MRS remains underutilized in clinical practice. MRS increases diagnostic yield and provides therapeutic measures. Because many inborn metabolic errors are now treatable, early diagnosis is crucial to prevent or curb permanent brain injury. Therefore, patients with known or suspected inborn metabolic errors stand to benefit from the addition of MRS. With education and practice, all neuroradiologists can perform and interpret MRS notwithstanding their training and prior experience. In this two-part review, we cover the requisite concepts for clinical MRS interpretation including technical considerations and normal brain spectral patterns based on age, location, and methodology.

Ketogenic diet reduces alcohol withdrawal symptoms in humans and alcohol intake in rodents

Individuals with alcohol use disorder (AUD) show elevated brain metabolism of acetate at the expense of glucose. We hypothesized that a shift in energy substrates during withdrawal may contribute to withdrawal severity and neurotoxicity in AUD and that a ketogenic diet (KD) may mitigate these effects. We found that inpatients with AUD randomized to receive KD (n = 19) required fewer benzodiazepines during the first week of detoxification, in comparison to those receiving a standard American (SA) diet (n = 14). Over a 3-week treatment, KD compared to SA showed lower "wanting" and increased dorsal anterior cingulate cortex (dACC) reactivity to alcohol cues and altered dACC bioenergetics (i.e., elevated ketones and glutamate and lower neuroinflammatory markers). In a rat model of alcohol dependence, a history of KD reduced alcohol consumption. We provide clinical and preclinical evidence for beneficial effects of KD on managing alcohol withdrawal and on reducing alcohol drinking.

Maintenance of Energy Homeostasis during Calorically Restricted Ketogenic Diet and Fasting-MR-Spectroscopic Insights from the ERGO2 Trial

Simple Summary

The glioblastoma is a highly malignant brain tumor with very limited treatment options up to date. Metabolism of this tumor is highly dependent on glucose uptake. It is believed that glioblastoma cells cannot metabolize ketone bodies, which are found in the blood during periods of fasting or ketogenic dieting. According to this hypothesis, dieting could lead to cancer cell starvation. The ERGO2 (Ernaehrungsumstellung bei Patienten mit Rezidiv eines Glioblastoms) MR-spectroscopic imaging subtrial was designed to investigate tumor metabolism in patients randomized to calorically restricted ketogenic diet/intermittent fasting versus standard diet. The non-invasive investigation of tumor metabolism is of high clinical interest.

Abstract

Background: The ERGO2 (Ernaehrungsumstellung bei Patienten mit Rezidiv eines Glioblastoms) MR-spectroscopic imaging (MRSI) subtrial investigated metabolism in patients randomized to calorically restricted ketogenic diet/intermittent fasting (crKD-IF) versus standard diet (SD) in addition to re-irradiation (RT) for recurrent malignant glioma. Intracerebral concentrations of ketone bodies (KB), intracellular pH (pH_i), and adenosine triphosphate (ATP) were non-invasively determined. Methods: 50 patients were randomized (1:1): Group A keeping a crKD-IF for nine days, and Group B a SD. RT was performed on day 4–8. Twenty-three patients received an extended MRSI-protocol (¹H decoupled ³¹P MRSI with 3D chemical shift imaging (CSI) and 2D ¹H point-resolved spectroscopy (PRESS)) at a 3T scanner at baseline and on day 6. Voxels were selected from the area of recurrent tumor and contralateral hemisphere. Spectra were analyzed with LCModel, adding simulated signals of 3-hydroxybutyrate (βOHB), acetone (Acn) and acetoacetate (AcAc) to the standard basis set. Results: Acn was the only reliably MRSI-detectable KB within tumor tissue and/or normal appearing white matter (NAWM). It was detected in 4/11 patients in Group A and in 0/8 patients in Group B. MRSI results showed no significant depletion of ATP in tumor tissue of patients at day 6 during crKD-IF, even though there were a significant difference in ketone serum levels between Group A and B at day 6 and a decline in fasting glucose in Group A from baseline to day 6. The tumor specific alkaline pH_i was maintained. Conclusions: Our metabolic findings suggest that tumor cells maintain energy homeostasis even with reduced serum glucose levels and may generate additional ATP through other sources.

Cerebral Ketones Detected by 3T MR Spectroscopy in Patients with High-Grade Glioma on an Atkins-Based Diet

BACKGROUND AND PURPOSE

Ketogenic diets are being explored as a possible treatment for several neurological diseases, but the physiologic impact on the brain is unknown. The objective of this study was to evaluate the feasibility of 3T MR spectroscopy to monitor brain ketone levels in patients with high-grade gliomas who were on a ketogenic diet (a modified Atkins diet) for 8 weeks.

MATERIALS AND METHODS

Paired pre- and post-ketogenic diet MR spectroscopy data from both the lesion and contralateral hemisphere were analyzed using LCModel software in 10 patients.

RESULTS

At baseline, the ketone bodies acetone and β-hydroxybutyrate were nearly undetectable, but by week 8, they increased in the lesion for both acetone (0.06 ± 0.03 ≥ 0.27 ± 0.06 IU, P = .005) and β-hydroxybutyrate (0.07 ± 0.07 ≥ 0.79 ± 0.32 IU, P = .046). In the contralateral brain, acetone was also significantly increased (0.041 ± 0.01 ≥ 0.16 ± 0.04 IU, P = .004), but not β-hydroxybutyrate. Acetone was detected in 9/10 patients at week 8, and β-hydroxybutyrate, in 5/10. Acetone concentrations in the contralateral brain correlated strongly with higher urine ketones (r = 0.87, P = .001) and lower fasting glucose (r = -0.67, P = .03). Acetoacetate was largely undetectable. Small-but-statistically significant decreases in NAA were also observed in the contralateral hemisphere at 8 weeks.

CONCLUSIONS

This study suggests that 3T MR spectroscopy is feasible for detecting small cerebral metabolic changes associated with a ketogenic diet, provided that appropriate methodology is used.

Detection of elevated ketone bodies by postmortem 1H-MRS in a case of fetal ketoacidosis

We report a fetal loss following maternal ketoacidosis in a case of cryptic pregnancy. Biochemical analysis of peripheral blood revealed highly elevated levels of beta-hydroxybutyrate (BHB) in the mother (9.2 mmol/l) and the fetus (4.2 mmol/l). Fetal ketoacidosis with hypoxic-ischemic brain damage was determined to be the cause of death. ¹H-MRS of the right cerebral hemisphere presented with distinctive resonances of BHB and acetone. Acetoacetate and glucose were not detected. Due to reported chronic abuse of ethanol and a period of fasting, alcoholic ketoacidosis was concluded to be the cause of the metabolic disorder. ¹H-MRS is a viable examination for the postmortem detection of ketone bodies and may be a key supplement to noninvasive fetal autopsy for the diagnosis of ketoacidosis.

β-Hydroxybutyrate Detection with Proton MR Spectroscopy in Children with Drug-Resistant Epilepsy on the Ketogenic Diet

BACKGROUND AND PURPOSE

The ketogenic diet, including both classic and modified forms, is an alternative to antiepileptic medications used in the treatment of drug-resistant epilepsy. We sought to evaluate the utility of proton MR spectroscopy for the detection of β-hydroxybutyrate in a cohort of children with epilepsy treated with the ketogenic diet and to correlate brain parenchymal metabolite ratios obtained from spectroscopy with β-hydroxybutyrate serum concentrations.

MATERIALS AND METHODS

Twenty-three spectroscopic datasets acquired at a TE of 288 ms in children on the ketogenic diet were analyzed with LCModel using a modified basis set that included a simulated β-hydroxybutyrate resonance. Brain parenchymal metabolite ratios were calculated. Metabolite ratios were compared with serum β-hydroxybutyrate concentrations, and partial correlation coefficients were calculated using patient age as a covariate.

RESULTS

β-hydroxybutyrate blood levels were highly correlated to brain β-hydroxybutyrate levels, referenced as either choline, creatine, or N-acetylaspartate. They were inversely but more weakly associated with N-acetylaspartate, regardless of the ratio denominator. No strong concordance with lactate was demonstrated.

CONCLUSIONS

Clinical MR spectroscopy in pediatric patients on the ketogenic diet demonstrated measurable β-hydroxybutyrate, with a strong correlation to β-hydroxybutyrate blood levels. These findings may serve as an effective tool for noninvasive monitoring of ketosis in this population. An inverse correlation between serum β-hydroxybutyrate levels and brain tissue N-acetylaspartate suggests that altered amino acid handling contributes to the antiepileptogenic effect of the ketogenic diet.