The behavioural and pathophysiological effects of the ketogenic diet on mild traumatic brain injury in adolescent rats.

Mild traumatic brain injury (mTBI), caused by an insult to the head, results in a cascade of molecular imbalance that includes altered glucose metabolism, mitochondrial dysfunction, and increases in reactive oxygen species. Although glucose is the primary energy source for the brain, it becomes an inefficient substrate following injury, and the brain is primed to use alternative substrates (such as ketones). The ketogenic diet (KD), a high-fat, low-carbohydrate diet, forces the brain to utilize ketones over glucose for energy. Given that mTBIs are commonly experienced during adolescence, our study sought to examine the effects of the KD on recovery from mTBI in adolescent rats. This was done via two experiments; the first of which animals were fed the KD prior to a mTBI in order to investigate the neuroprotective potential of the diet, and the second the animals were fed the KD following a mTBI to examine the therapeutic potential. Male and female Sprague Dawley rats were assigned to receive a control standard diet or the KD (either pre-injury or post-injury), then further randomized to receive a sham or mTBI. Animals were tested on 6 behavioural measures designed to examine post-concussive symptomology, and mRNA analysis of the brain and small intestine were performed. Pre-injury exposure to the KD offered some neuroprotection, reducing balance and motor impairments while increasing exploratory behaviour and telomere length. Consumption of the KD following the injury also provided some therapeutic benefit, reducing both anxiety- and depressive-like behaviours. The timing of KD administration also differentially modified expression of prefrontal cortex, hippocampus, and intestinal mRNA for our genes of interest (Fgf2, Iba1, Opa1, Sirt1, Claudin3, OCC, and ZO1) This study demonstrates the neuroprotective and therapeutic potential of the KD for mTBI and warrants further investigation.

Proton Magnetic Resonance Spectroscopy (H1-MRS) Study of the Ketogenic Diet on Repetitive Mild Traumatic Brain Injury in Adolescent Rats and Its Effect on Neurodegeneration.

OBJECTIVE: A ketogenic diet (KD) improves cellular metabolism and functional recovery after moderate-to-severe traumatic brain injury. Here, we evaluated the changes of neurochemical metabolites after KD therapy for repetitive mild traumatic brain injury (rmTBI) and its possible role in neurodegeneration. METHODS: Postnatal day 35 rats were randomly divided into 3 groups: sham, control, and KD groups. Rats in control and KD groups were given 3 rmTBI by a fluid percussion traumatic brain injury device 24 hours apart. All rats were killed at 7 days after the last injury. The ipsilateral cortex were analyzed with hematoxylin and eosin staining; beta-hydroxybutyrate was measured; conventional magnetic resonance imaging and the dry-wet weight method were used to assess the brain edema; changes of neurochemical metabolites were assessed using the ratio of N-acetylaspartate (NAA)/creatine (Cr), choline compound (Cho)/Cr, and NAA/Cho with magnetic resonance spectroscopy; the effect of KD therapy on neurodegeneration was evaluated with double immunofluorescence staining of Iba-1/beclin-1; behavioral outcome was assessed with beam walk/beam balance tests. RESULTS: KD significantly elevated beta-hydroxybutyrate levels, and there was no brain edema associated with rmTBI and KD therapy; behavioral assessment showed KD therapy significantly improved motor performance; magnetic resonance spectroscopy showed that rmTBI reduced the ratio of NAA/Cr and had no effect on the ratios of Cho/Cr and NAA/Cho whereas KD increased the ratio of NAA/Cr; double immunofluorescence staining showed KD therapy could significantly decrease microglial beclin-1 expression in the ipsilateral cortex. CONCLUSIONS: These results suggest the effect of KD on metabolic status and its possible role in preventing neurodegeneration in adolescent rats after rmTBI.

Memory Deficit in an Object Location Task after Mild Traumatic Brain Injury Is Associated with Impaired Early Object Exploration and Both Are Restored by Branched Chain Amino Acid Dietary Therapy.

The relation between traumatic brain injury (TBI) and memory dysfunction is well established, yet imprecise. Here, we investigate whether mild TBI causes a specific deficit in spatial episodic memory. Fifty-eight (29 TBI, 29 sham) mice were run in a spatial recognition task. To determine which phase of memory might be affected in our task, we assessed rodent performance at three different delay times (3 min, 1 h, and 24 h). We found that sham and TBI mice performed equally well at 3 min, but TBI mice had significantly impaired spatial recognition memory after a delay time of 1 h. Neither sham nor injured mice remembered the test object locations after a 24-h delay. In addition, the TBI-specific impairment was accompanied by a decrease in exploratory behavior during the first 3 mins of the initial exposure to the test objects. These memory and exploratory behavioral deficits were linked as branched-chain amino acid (BCAA) dietary therapy restored both memory performance and normal exploratory behavior. Our findings 1) support the use of BCAA therapy as a potential treatment for mild TBI and 2) suggest that poor memory performance post-TBI is associated with a deficit in exploratory behavior that is likely to underlie the encoding needed for memory formation.

The Role of Nutritional Supplements in Sports Concussion Treatment.

There has been considerable research conducted in regard to the prevention and treatment of concussions. Numerous supplements and vitamins are being used throughout the country to help patients recover from concussions; however, to date, there are no completed human-based studies specifically examining supplement and vitamin use for the treatment or prevention of concussions. This article examines the most current evidence regarding supplements and vitamins for the treatment and prevention of concussions. The supplements and vitamins reviewed include omega-3 fatty acids, curcumin, resveratrol, melatonin, creatine, and Scutellaria baicalensis.

Diet, age, and prior injury status differentially alter behavioral outcomes following concussion in rats.

Mild traumatic brain injury (mTBI) or concussion affects a large portion of the population and although many of these individuals recover completely, a small subset of people experience lingering symptomology and poor outcomes. Little is known about the factors that affect individual susceptibility or resilience to poor outcomes after mTBI and there are currently no biomarkers to delineate mTBI diagnosis or prognosis. Based upon the growing literature associated with caloric intake and altered neurological aging and the ambiguous link between repetitive mTBI and progressive neurodegeneration, the current study was designed to examine the effect of a high fat diet (HFD), developmental age, and repetitive mTBI on behavioral outcomes following a mTBI. In addition, telomere length was examined before and after experimental mTBI. Sprague Dawley rats were maintained on a HFD or standard rat chow throughout life (including the prenatal period) and then experienced an mTBI/concussion at P30, P30 and P60, or only at P60. Behavioral outcomes were examined using a test battery that was administered between P61-P80 and included; beam-walking, open field, elevated plus maze, novel context mismatch, Morris water task, and forced swim task. Animals with a P30 mTBI often demonstrated lingering symptomology that was still present during testing at P80. Injuries at P30 and P60 rarely produced cumulative effects, and in some tests (i.e., beam walking), the first injury may have protected the brain from the second injury. Exposure to the high fat diet exacerbated many of the behavioral deficits associated with concussion. Finally, telomere length was shortened following mTBI and was influenced by the animal's dietary intake. Diet, age at the time of injury, and the number of prior concussion incidents differentially contribute to behavioral deficits and may help explain individual variations in susceptibility and resilience to poor outcomes following an mTBI.

The collective therapeutic potential of cerebral ketone metabolism in traumatic brain injury.

The postinjury period of glucose metabolic depression is accompanied by adenosine triphosphate decreases, increased flux of glucose through the pentose phosphate pathway, free radical production, activation of poly-ADP ribose polymerase via DNA damage, and inhibition of glyceraldehyde dehydrogenase (a key glycolytic enzyme) via depletion of the cytosolic NAD pool. Under these post-brain injury conditions of impaired glycolytic metabolism, glucose becomes a less favorable energy substrate. Ketone bodies are the only known natural alternative substrate to glucose for cerebral energy metabolism. While it has been demonstrated that other fuels (pyruvate, lactate, and acetyl-L-carnitine) can be metabolized by the brain, ketones are the only endogenous fuel that can contribute significantly to cerebral metabolism. Preclinical studies employing both pre- and postinjury implementation of the ketogenic diet have demonstrated improved structural and functional outcome in traumatic brain injury (TBI) models, mild TBI/concussion models, and spinal cord injury. Further clinical studies are required to determine the optimal method to induce cerebral ketone metabolism in the postinjury brain, and to validate the neuroprotective benefits of ketogenic therapy in humans.