scholarly journals Ketosis Proportionately Spares Glucose Utilization in Brain

2013 ◽  
Vol 33 (8) ◽  
pp. 1307-1311 ◽  
Author(s):  
Yifan Zhang ◽  
Youzhi Kuang ◽  
Kui Xu ◽  
Donald Harris ◽  
Zhenghong Lee ◽  
...  

The brain is dependent on glucose as a primary energy substrate, but is capable of utilizing ketones such as β-hydroxybutyrate and acetoacetate, as occurs with fasting, starvation, or chronic feeding of a ketogenic diet. The relationship between changes in cerebral metabolic rates of glucose (CMRglc) and degree or duration of ketosis remains uncertain. To investigate if CMRglc decreases with chronic ketosis, 2-[18F]fluoro-2-deoxy-D-glucose in combination with positron emission tomography, was applied in anesthetized young adult rats fed 3 weeks of either standard or ketogenic diets. Cerebral metabolic rates of glucose (μmol/min per 100 g) was determined in the cerebral cortex and cerebellum using Gjedde-Patlak analysis. The average CMRglc significantly decreased in the cerebral cortex (23.0 ±4.9 versus 32.9 ±4.7) and cerebellum (29.3 ± 8.6 versus 41.2 ±6.4) with increased plasma ketone bodies in the ketotic rats compared with standard diet group. The reduction of CMRg|c in both brain regions correlates linearly by ∼9% for each 1 mmol/L increase of total plasma ketone bodies (0.3 to 6.3 mmol/L). Together with our meta-analysis, these data revealed that the degree and duration of ketosis has a major role in determining the corresponding change in CMRglc with ketosis.

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2681
Author(s):  
Viggiano ◽  
Meccariello ◽  
Santoro ◽  
Secondulfo ◽  
Operto ◽  
...  

The antiepileptic effect of ketogenic diets is acknowledged but its mechanism of action is poorly understood. The present work aimed to evaluate possible effects of a calorie-restricted ketogenic diet (CRKD) on brain growth and angiogenesis in normal prepubertal rats. Two groups of prepubertal rats were fed with a standard diet (group 1) or a CRKD (group 2) for ten weeks. Then, rats were sacrificed and the thickness for the following structures was evaluated by histology: (1) cerebral cortex, (2) deep cerebral white matter, and (3) substantia nigra. The capillary density was also evaluated within: (1) cerebral cortex, (2) dentate gyrus of the hippocampus, (3) periaqueductal grey matter, and (4) substantia nigra. The results showed a smaller thickness of all the areas examined and a reduced capillary density within the cerebral cortex in the CRKD-treated group compared to the control group. These findings suggest an association between reduced angiogenesis within the cerebral cortex and the antiepileptic effects of CRKD.


2010 ◽  
Vol 30 (10) ◽  
pp. 1549-1560 ◽  
Author(s):  
Ibtissem Ben Amara ◽  
Ahmed Hakim ◽  
Afef Troudi ◽  
Nejla Soudani ◽  
Fatma Ayadi Makni ◽  
...  

The present study investigates the potential ability of selenium, considered as an antioxidant with pharmacological property to alleviate oxidative stress and hematological parameter disorders induced by methimazole, an antithyroid drug. Pregnant Wistar rats were randomly divided into four groups of six each: group I served as negative control and received a standard diet; group II received 250 mg/L of methimazole in drinking water and a standard diet; group III received both methimazole (250 mg/L, orally) and selenium (0.5 mg/kg of diet) supplemented to the standard diet; group IV served as positive control and received a supplement of selenium in the diet (0.5 mg/kg of diet) as sodium selenite (Na2SeO3). Treatment was started from the 14th day of pregnancy until day 14 after delivery. Methimazole reduced the number of red blood cells, hemoglobin concentration and hematocrit in mothers and their pups. Besides, plasma iron, vitamins B9, B12, C and E levels were reduced. Lipid peroxidation increased, objectified by high malondialdehyde levels and lactate dehydrogenase activity in plasma, while glutathione, glutathione peroxidase, superoxide dismutase and catalase activities showed a significant decline. Co-administration of selenium through diet improved all the parameters cited above. It can be concluded that the administration of selenium alleviates methimazole-induced toxicity, thus demonstrating its antioxidant efficacy.


2007 ◽  
Vol 292 (6) ◽  
pp. E1607-E1615 ◽  
Author(s):  
Michelle A. Puchowicz ◽  
Kui Xu ◽  
Xiaoyan Sun ◽  
Andre Ivy ◽  
Doug Emancipator ◽  
...  

It is recognized that ketone bodies, such as R-β-hydroxybutyrate (β-HB) and acetoacetate, are energy sources for the brain. As with glucose metabolism, monocarboxylate uptake by the brain is dependent on the function and regulation of its own transporter system. We concurrently investigated ketone body influx, blood flow, and regulation of monocarboxylate transporter (MCT-1) and glucose transporter (GLUT-1) in diet-induced ketotic (KG) rat brain. Regional blood-to-brain β-HB influx (μmol·g−1·min−1) increased 40-fold with ketosis (4.8 ± 1.8 plasmaβ-HB; mM) in all regions compared with the nonketotic groups (standard and no-fat diets); there were no changes in regional blood flow. Immunohistochemical staining revealed that GLUT-1 density (number/mm2) in the cortex was significantly elevated (40%) in the ketotic group compared with the standard and no-fat diet groups. MCT-1 was also markedly (3-fold) upregulated in the ketotic group compared with the standard diet group. In the standard diet group, 40% of the brain capillaries stained positive for MCT-1; this amount doubled with the ketotic diet. Western blot analysis of isolated microvessels from ketotic rat brain showed an eightfold increase in GLUT-1 and a threefold increase in MCT-1 compared with the standard diet group. These data suggest that diet-induced ketosis results in increased vascular density at the blood-brain barrier without changes in blood flow. The increase in extraction fraction and capillary density with increased plasma ketone bodies indicates a significant flux of substrates available for brain energy metabolism.


Author(s):  
José Carlos Pastrana-Trejo ◽  
Fátima Duarte-Aké ◽  
Rosa Us-Camas ◽  
Clelia De-la-Peña ◽  
Linda Parker ◽  
...  

Background: Cannabidiol (CBD), a non-psychotropic constituent of Cannabis sativa, has shown therapeutic promises by modulating several pathological conditions, including pain, epilepsy autism, among others. However, the molecular mechanism of action of CBD remains unknown and recent data suggest the engagement on CBD´s effects of nuclear elements, such as histone activity. Aim: This study assessed the changes on the post-translational modification (PTM) on the histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 in several brain regions of rats after the administration of CBD (20mg/Kg/i.p.). Objective: To evaluate the effects on the PTM of histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 levels in the cerebral cortex, hypothalamus and pons of CBD-treated rats. Method: Ten adult rats were randomly assigned into 2 groups: Control or CBD (20mg/Kg/i.p). Animals were sacrificed after treatments and brains were collected for dissections of the cerebral cortex, hypothalamus and pons. Samples were analyzed for PTM on the histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 levels by Western blot procedure. Results: CBD increased the PTM levels on the histones H3K4Me3, H3K9ac, and H3K27Me3 in the cerebral cortex whereas no significant differences were found in H3K9Me2 and H3K36Me2. In addition, in the hypothalamus, CBD decreased the contents of H3K9ac while no significant effects were observed in H3K4Me3, H3K9Me2, H3K27Me3, and H3K36Me2. Lastly, in the pons, CBD-treated rats showed a significant decline on the PTM levels of H3K4Me3 whereas no statistical differences were found in H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2. Conclusion: The study showed that CBD induced differential effects in levels of PTM on the histones H3K4Me3, H3K9ac, H3K9Me2, H3K27Me3, and H3K36Me2 in several brain regions.


2019 ◽  
Author(s):  
Zachary Hawes ◽  
H Moriah Sokolowski ◽  
Chuka Bosah Ononye ◽  
Daniel Ansari

Where and under what conditions do spatial and numerical skills converge and diverge in the brain? To address this question, we conducted a meta-analysis of brain regions associated with basic symbolic number processing, arithmetic, and mental rotation. We used Activation Likelihood Estimation (ALE) to construct quantitative meta-analytic maps synthesizing results from 86 neuroimaging papers (~ 30 studies/cognitive process). All three cognitive processes were found to activate bilateral parietal regions in and around the intraparietal sulcus (IPS); a finding consistent with shared processing accounts. Numerical and arithmetic processing were associated with overlap in the left angular gyrus, whereas mental rotation and arithmetic both showed activity in the middle frontal gyri. These patterns suggest regions of cortex potentially more specialized for symbolic number representation and domain-general mental manipulation, respectively. Additionally, arithmetic was associated with unique activity throughout the fronto-parietal network and mental rotation was associated with unique activity in the right superior parietal lobe. Overall, these results provide new insights into the intersection of numerical and spatial thought in the human brain.


Diseases ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 39
Author(s):  
Prakrati Acharya ◽  
Chirag Acharya ◽  
Charat Thongprayoon ◽  
Panupong Hansrivijit ◽  
Swetha R. Kanduri ◽  
...  

Very-low-carbohydrate diets or ketogenic diets are frequently used for weight loss in adults and as a therapy for epilepsy in children. The incidence and characteristics of kidney stones in patients on ketogenic diets are not well studied. Methods: A systematic literature search was performed, using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from the databases’ inception through April 2020. Observational studies or clinical trials that provide data on the incidence and/or types of kidney stones in patients on ketogenic diets were included. We applied a random-effects model to estimate the incidence of kidney stones. Results: A total of 36 studies with 2795 patients on ketogenic diets were enrolled. The estimated pooled incidence of kidney stones was 5.9% (95% CI, 4.6–7.6%, I2 = 47%) in patients on ketogenic diets at a mean follow-up time of 3.7 +/− 2.9 years. Subgroup analyses demonstrated the estimated pooled incidence of kidney stones of 5.8% (95% CI, 4.4–7.5%, I2 = 49%) in children and 7.9% (95% CI, 2.8–20.1%, I2 = 29%) in adults, respectively. Within reported studies, 48.7% (95% CI, 33.2–64.6%) of kidney stones were uric stones, 36.5% (95% CI, 10.6–73.6%) were calcium-based (CaOx/CaP) stones, and 27.8% (95% CI, 12.1–51.9%) were mixed uric acid and calcium-based stones, respectively. Conclusions: The estimated incidence of kidney stones in patients on ketogenic diets is 5.9%. Its incidence is approximately 5.8% in children and 7.9% in adults. Uric acid stones are the most prevalent kidney stones in patients on ketogenic diets followed by calcium-based stones. These findings may impact the prevention and clinical management of kidney stones in patients on ketogenic diets.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ravi L. Rungta ◽  
Marc Zuend ◽  
Ali-Kemal Aydin ◽  
Éric Martineau ◽  
Davide Boido ◽  
...  

AbstractThe spatial-temporal sequence of cerebral blood flow (CBF), cerebral blood volume (CBV) and blood velocity changes triggered by neuronal activation is critical for understanding functional brain imaging. This sequence follows a stereotypic pattern of changes across different zones of the vasculature in the olfactory bulb, the first relay of olfaction. However, in the cerebral cortex, where most human brain mapping studies are performed, the timing of activity evoked vascular events remains controversial. Here we utilized a single whisker stimulation model to map out functional hyperemia along vascular arbours from layer II/III to the surface of primary somatosensory cortex, in anesthetized and awake Thy1-GCaMP6 mice. We demonstrate that sensory stimulation triggers an increase in blood velocity within the mid-capillary bed and a dilation of upstream large capillaries, and the penetrating and pial arterioles. We report that under physiological stimulation, response onset times are highly variable across compartments of different vascular arbours. Furthermore, generating transfer functions (TFs) between neuronal Ca2+ and vascular dynamics across different brain states demonstrates that anesthesia decelerates neurovascular coupling (NVC). This spatial-temporal pattern of vascular events demonstrates functional diversity not only between different brain regions but also at the level of different vascular arbours within supragranular layers of the cerebral cortex.


2014 ◽  
Vol 8 ◽  
pp. 36 ◽  
Author(s):  
Alice A. Gibson ◽  
Radhika V. Seimon ◽  
Crystal M.Y. Lee ◽  
Julie Ayre ◽  
Janet Franklin ◽  
...  

1998 ◽  
Vol 329 (2) ◽  
pp. 373-381 ◽  
Author(s):  
E. Tim CULLINGFORD ◽  
T. Colin DOLPHIN ◽  
K. Kishore BHAKOO ◽  
Stefan PEUCHEN ◽  
Laura CANEVARI ◽  
...  

We have investigated, by RNase protection assays in rat brain regions and primary cortical astrocyte cultures, the presence of the mRNA species encoding the three mitochondrially located enzymes acetoacetyl-CoA thiolase, mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (mt. HMG-CoA synthase) and HMG-CoA lyase (HMG-CoA lyase) that together constitute the ketogenic HMG-CoA cycle. As a prerequisite we obtained a full-length cDNA encoding rat HMG-CoA lyase by degenerate oligonucleotide-primed PCR coupled to a modification of PCR-rapid amplification of cDNA ends (PCR-RACE). We report here: (1) the nucleotide sequence of rat mt. HMG-CoA lyase, (2) detection of the mRNA species encoding all three HMG-CoA cycle enzymes in all regions of rat brain during suckling, (3) approximately twice the abundance of mt. HMG-CoA synthase mRNA in cerebellum than in cortex in 11-day-old suckling rat pups, (4) significantly lower abundances of mt. HMG-CoA synthase mRNA in brain regions derived from rats weaned to a high-carbohydrate/low-fat diet compared with the corresponding regions derived from the suckling rat, and (5) the presence of mt. HMG-CoA synthase mRNA in primary cultures of neonatal cortical astrocytes at an abundance similar to that found in liver of weaned animals. These results provide preliminary evidence that certain neural cell types possess ketogenic potential and might thus have a direct role in the provision of fatty acid-derived ketone bodies during the suckling period.


Diabetology ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 190-204
Author(s):  
Ahmed Al-Humadi ◽  
Athina Strilakou ◽  
Hussam Al-Humadi ◽  
Rafal Al-Saigh ◽  
Emmanouel Agapitos ◽  
...  

Choline (Ch) is an essential molecule of substantial importance for the optimal development and function of several biological systems. Ch deprivation has been linked with abnormal fat metabolism, insulin resistance, and myocardial dysfunction. The current study provides evidence of an exacerbation of streptozotocin-induced cardiomyopathy in adult diabetic Wistar rats by dietary Ch deprivation through the administration of a Ch-deprived diet (CDD). Twenty-four adult male Wistar rats were randomly separated into four groups: control, diabetic (DM), choline-deprived through choline-deprived diet (CD), and diabetic choline-deprived (DM + CD). After five weeks of dietary intervention, myocardium echocardiographic and histological assessments were performed. Choline-deprived diabetic rats exhibited significantly slower heart rate, significantly higher myocardial ejection velocity and left ventricle wall tension index with a concomitant significant decreased LV posterior wall thickness as compared to diabetic rats fed on a standard diet. Moreover, histopathological evidence demonstrated an exacerbation of myocardial inflammation and fibrosis associated with significant up-regulation of VEGF expression in the diabetic rat myocardium as a result of Ch deprivation. The study’s findings are of particular significance since the examined experimental approach introduces a previously uncharacterised comorbidity simulation with regards to myocardial structure and functional profiling.


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