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We assessed in vivo rates of hepatic mitochondrial oxidation, gluconeogenesis, and β-hydroxybutyrate (β-OHB) turnover by positional isotopomer NMR tracer analysis (PINTA) in individuals with metabolic-dysfunction-associated steatotic liver (MASL) (fatty liver) and MASL disease (MASLD) (steatohepatitis) compared with BMI-matched control participants with no hepatic steatosis. Hepatic fat content was quantified by localized 1H magnetic resonance spectroscopy (MRS). We found that in vivo rates of hepatic mitochondrial oxidation were unaltered in the MASL and MASLD groups compared with the control group. A physiological increase in plasma glucagon concentrations increased in vivo rates of hepatic mitochondrial oxidation by 50%–75% in individuals with and without MASL and increased rates of glucose production by ∼50% in the MASL group, which could be attributed in part to an ∼30% increase in rates of mitochondrial pyruvate carboxylase flux. These results demonstrate that (1) rates of hepatic mitochondrial oxidation are not substantially altered in individuals with MASL and MASLD and (2) glucagon increases rates of hepatic mitochondrial oxidation. [Display omitted] • Hepatic mitochondrial oxidation is not altered in humans with fatty liver • Hepatic mitochondrial oxidation is not altered in humans with steatohepatitis • Glucagon increases hepatic mitochondrial oxidation in humans without fatty liver • Glucagon increases hepatic mitochondrial oxidation in humans with fatty liver It is unclear whether rates of hepatic mitochondrial oxidation are altered in individuals with MASLD and MASH. Here, Petersen et al. show that rates of hepatic mitochondrial oxidation are not altered in humans with fatty liver or steatohepatitis and that glucagon can increase rates of hepatic mitochondrial oxidation in humans with and without fatty liver by 50%–75%. [ABSTRACT FROM AUTHOR]

The heart and kidney have a high energy requirement, but relatively little is known about their utilization of ketones as a potential energy source. We assessed the metabolism of the ketone tracer, carbon-11 acetoacetate (11C-AcAc), by the left and right ventricles of the heart and by the kidney using positron emission tomography (PET) in n = 10 healthy adults under four experimental conditions: a 4-h fast (fasted) ± a single 12 g oral dose of D-beta-hydroxybutyrate (D-BHB), and a single complete, liquid replacement meal (hereafter referred to as the "fed" condition) ± a single 12 g oral dose of D-BHB. Under these experimental conditions, the kinetics of 11C-AcAc metabolism fitted a two-compartment model in the heart and a three-compartment model in the kidney. Plasma ketones were about 10-fold higher with the oral dose of D-BHB. During the four conditions, tracer kinetics were broadly similar in the myocardium and kidney cortex. 11C-AcAc metabolism by the kidney pelvis was similar in three of the four study conditions but, later, peaked significantly higher than that in the cortex; the exception was that the tracer uptake was significantly lower in the fed condition without D-BHB. 11C-AcAc uptake was significantly inversely correlated with age in the kidney cortex, and its oxidative metabolism was significantly positively correlated with age in the left ventricle. D-BHB blunted the insulin, gastric inhibitory peptide, and C-peptide response to the meal. This PET methodology and these acute metabolic perturbations would be suitable for future studies assessing cardiorenal ketone metabolism in conditions in which heart and kidney functions are experimentally modified or compromised by disease. [ABSTRACT FROM AUTHOR]

Ketosis, evidenced by hyperketonemia with elevated blood β‐hydroxybutyrate (BHB) levels, is a significant metabolic disorder of dairy cattle, typically diagnosed within the first 6 weeks post‐calving when high energy levels are essential to milk production. Our study aimed to identify genetic markers linked to hyperketonemia (HYK) patterns in Holstein cows during early lactation and compare these to HYK‐negative cows. We screened 964 cows for HYK using a threshold of BHB ≥1.2 mmol/L during the first 2 weeks postpartum (screening period, SP). Cows that tested negative initially were retested the following week. Cows were deemed HYK‐negative (CON group) if BHB levels were below 1.2 mmol/L in both tests, while those with BHB levels exceeding this threshold at any test were treated and classified as HYK‐positive (HYK+). Post‐treatment, HYK+ cows were monitored for two‐week follow‐up period (FP) and classified based on their recovery: cured (CUR; consistently low BHB), recurrent (REC; fluctuating BHB levels), severe (SEV; high initial BHB that decreased), or chronic (CHR; persistently high BHB). Using 489 cows that were genotyped, a GWAS was conducted using GCTA software, revealing significant associations of several SNPs across different HYK patterns when compared to the CON group. These SNPs were primarily linked to genes affecting milk traits and were enriched in biological pathways relevant to protein glycosylation, inflammatory response, glucose homeostasis, and fatty acid synthesis. Our findings highlight genomic regions, potential candidate genes, and biological pathways related to ketosis, underscoring potential targets for improving health management in dairy cattle. These insights could lead to better strategies for managing ketosis through genetic selection, ultimately enhancing dairy cattle welfare and productivity. Further research with a larger number of cows is recommended to validate these findings and help confirm the implicated SNPs and genes. [ABSTRACT FROM AUTHOR]

Exogenous ketone supplements are a potential augmentation strategy for cognitive resilience during acute hypoxic exposure due to their capacity to attenuate the decline in oxygen (O2) availability, and by providing an alternative substrate for cerebral metabolism. Utilizing a single‐blind randomized crossover design, 16 male military personnel (age, 25.3 ± 2.4 year, body mass, 86.2 ± 9.3 kg) performed tests of cognitive performance at rest in three environments: room air (baseline), normoxia (20 min; 0 m; 20.9% O2) and hypoxia (20 min; 6096 m, 9.7% O2) using a reduced O2 breathing device (ROBD). (R)‐3‐Hydroxybutyl (R)‐3‐hydroxybutyrate (R‐BD R‐βHB) ketone monoester (KME; 650 mg/kg, split dose given at 30 min prior to each exposure) or taste‐matched placebo (PLA) was ingested prior to normoxia and hypoxic exposure. Blood R‐βHB and glucose concentrations, cognitive performance and O2 saturation (SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$) were collected throughout. KME ingestion increased blood R‐βHB concentration, which was rapid and sustained (>4 mM 30 min post; P < 0.001) and accompanied by lower blood glucose concentration (∼20 mg/dL; P < 0.01) compared to PLA. Declines in cognitive performance during hypoxic exposure, assessed as cognitive efficiency during a Defense Automated Neurobehavioral Assessment (DANA) code substitution task, were attenuated with KME leading to 6.8 (95% CL: 1.0, 12.6) more correct responses per minute compared to PLA (P = 0.018). The decline in SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$ during hypoxic exposure was attenuated (6.40% SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$; 95% CL: 0.04, 12.75; P = 0.049) in KME compared to PLA (KME, 76.8 ± 6.4% SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$; PLA, 70.4 ± 7.4% SpO2${{S}_{{\mathrm{p}}{{{\mathrm{O}}}_{\mathrm{2}}}}}$). Acute ingestion of KME attenuated the decline in cognitive performance during acute severe hypoxic exposure, which coincided with attenuation of declines in O2 saturation. What is the central question of this study?Can exogenous ketosis act as a countermeasure to declines in blood oxygen saturation and cognitive performance during acute severe hypoxic exposure at rest?What is the main finding and its importance?Acute exogenous ketosis via ingestion of a drink containing the (R)‐3‐hydroxybutyl (R)‐3‐hydroxybutyrate ketone monoester prior to acute severe hypoxic exposure attenuated hypoxia‐induced declines in blood oxygen saturation and cognitive performance at rest. [ABSTRACT FROM AUTHOR]

Acute ingestion of exogenous ketone supplements in the form of a (R)‐3‐hydroxybutyl (R)‐3‐hydroxybutyrate (R‐BD R‐βHB) ketone monoester (KME) can attenuate declines in oxygen availability during hypoxic exposure and might impact cognitive performance at rest and in response to moderate‐intensity exercise. In a single‐blind randomized crossover design, 16 males performed assessments of cognitive performance before and during hypoxic exposure with moderate exercise [2 × 20 min weighted ruck (∼22 kg) at 3.2 km/h at 10% incline] in a normobaric altitude chamber (4572 m, 11.8% O2). The R‐BD R‐βHB KME (573 mg/kg) or a calorie‐ and taste‐matched placebo (∼50 g maltodextrin) were co‐ingested with 40 g of dextrose before exposure to hypoxia. The R‐βHB concentrations were rapidly elevated and sustained (>3 mM; P < 0.001) by KME. The decline in oxygen saturation during hypoxic exposure was attenuated in KME conditions by 2.4%–4.2% (P < 0.05) compared with placebo. Outcomes of cognitive performance tasks, in the form of the Defense Automated Neurobehavioral Assessment (DANA) code substitution task, the Stroop color and word task, and a shooting simulation, did not differ between trials before and during hypoxic exposure. These data suggest that the acute exogenous ketosis induced by KME ingestion can attenuate declining blood oxygen saturation during acute hypoxic exposure both at rest and during moderate‐intensity exercise, but this did not translate into differences in cognitive performance before or after exercise in the conditions investigated. What is the central question of this study?Can exogenous ketosis act as a countermeasure to declines in blood oxygen saturation and cognitive performance during acute hypoxic exposure while performing a weighted ruck exercise?What is the main finding and its importance?Acute exogenous ketosis via ingestion of a drink containing the (R)‐3‐hydroxybutyl (R)‐3‐hydroxybutyrate ketone monoester prior to acute hypoxic exposure attenuated hypoxia‐induced declines in blood oxygen saturation but had no effect on cognitive performance during exercise. [ABSTRACT FROM AUTHOR]

Aim: To investigate the effects of β‐hydroxybutyrate (BHB) and melatonin on brown adipose tissue (BAT) plasticity in rats fed a high‐fat diet (HFD). Methods: We employed a 7‐week experimental design for a study on 30 male Sprague–Dawley rats divided into five groups: (1) a control‐diet fed group; (2) a high‐fat diet (HFD)‐fed group; (3) a group that received an HFD and a BHB solution in their drinking water; (4) a group that received an HFD with 10 mg/kg/day melatonin in their drinking water; and (5) a group that received an HFD and were also treated with the combination of BHB and melatonin. Following the treatment period, biochemical indices, gene expression levels of key thermogenic markers (including uncoupling protein 1 [UCP1], PR domain containing 16 [PRDM16], Cidea, fat‐specific protein 27 [Fsp27], and metallothionein 1 [MT1]), and stereological assessments of BAT were evaluated. Results: Treatment with BHB and melatonin significantly boosted blood ketone levels, improved lipid profiles, and reduced weight gain from an HFD. It also downregulated genes linked to WAT, namely, Cidea and Fsp27, and upregulated key BAT markers, including UCP1, PRDM16 and peroxisome proliferator‐activated receptor‐gamma coactivator‐1‐alpha. Additionally, the co‐treatment increased MT1 receptor expression and enhanced the structural density of BAT. Conclusion: The combined oral administration of BHB and melatonin successfully prevented the whitening of BAT in obese rats fed an HFD, indicating its potential as a therapeutic strategy for obesity‐related BAT dysfunction. The synergistic effects of this treatment underscore the potential of a combined approach to address BAT dysfunction in obesity. [ABSTRACT FROM AUTHOR]

Introduction: Special Operations Forces (SOF) often conduct operations in physiologically stressful environments such as severe heat, cold, or hypoxia, which can induce decreases in a variety of cognitive abilities. Given the promising empirical demonstration of the efficacy of exogenous ketone monoester (KME) supplementation in attenuating cognitive performance decrease during hypoxia at rest in a laboratory setting, we conducted a real-world, field experiment examining KME's efficacy during high-altitude mountaineering, an austere environment in which US SOF have conducted increasing numbers of operations over the past two decades. Methods: Specifically, 34 students and cadre at the US Army 10th Special Forces Group Special Operations Advanced Mountaineering School (SOAMS) participated in a randomized, double-blind, placebo (PLA)-controlled crossover trial (KME vs. PLA) over 2 days of tactical mountain operations training. The participants ascended from 7,500 ft in altitude (basecamp) to 12,460 ft on 1 day and 13,627 ft the other day (in randomized order), while performing various training activities inducing high physical and cognitive loads over 8-12 h, and consumed six doses of KME or PLA 2-3 h apart throughout each training day. Results and Discussion: While KME increased blood ketone levels and decreased glucose levels, there were no clear indications that the elevated ketone level enhanced physical or cognitive performance. KME also produced a greater incidence of heartburn, nausea, and vomiting. In these elite operators, highaltitude mountaineering had a limited impact on cognitive performance, and KME supplementation did not demonstrate any benefit. [ABSTRACT FROM AUTHOR]

BackgroundMethodsResultsConclusionMedium-chain fatty acids (MCFAs) and docosahexaenoic acid (DHA) could affect the occurrence of mild cognitive impairment (MCI). β-hydroxybutyrate (BHB), mitochondrial DNA copy number (mtDNAcn) and mitochondrial DNA (mtDNA) deletions might be their potential mechanisms. This study aimed to explore the relationship between MCFAs, DHA and MCI, and potential mechanisms.This study used data from Tianjin Elderly Nutrition and Cognition (TENC) cohort study, 120 individuals were identified with new onset MCI during follow-up, 120 individuals without MCI were selected by 1:1 matching sex, age, and education levels as the control group from TENC. Conditional logistic regression analysis and mediation effect analysis were used to explore their relationship.Higher serum octanoic acid levels (OR: 0.633, 95% CI: 0.520, 0.769), higher serum DHA levels (OR: 0.962, 95% CI: 0.942, 0.981), and more mtDNAcn (OR: 0.436, 95% CI: 0.240, 0.794) were associated with lower MCI risk, while more mtDNA deletions was associated with higher MCI risk (OR: 8.833, 95% CI: 3.909, 19.960). Mediation analysis suggested that BHB and mtDNAcn, in series, have mediation roles in the association between octanoic acid and MCI risk, and mtDNA deletions have mediation roles in the association between DHA and MCI risk.Higher serum octanoic acid and DHA levels were associated with lower MCI risk. Octanoic acid could affect the incidence of MCI through BHB, then mitochondria function, or through mitochondria function, or directly. Serum DHA level could affect the incidence of MCI through mitochondria function, or directly. [ABSTRACT FROM AUTHOR]

The prevention and treatment of cardiovascular diseases have always been a focus of attention in related fields. This paper discusses the application and mechanism of exogenous and endogenous supplementation with β-hydroxybutyrate in the prevention and treatment of cardiovascular diseases such as myocardial ischemia, myocardial infarction, diabetic cardiomyopathy, hypertension, myocardial inflammation, hypertrophic cardiomyopathy and heart failure. Exogenous β-hydroxybutyrate supplementation can quickly and directly provide substitute energy for the heart and thus prevent and treat heart injury. The comprehensive effect of exogenous β-hydroxybutyrate supplementation is significantly better than that of endogenous β-hydroxybutyrate. Endogenous fatty acid, obtained through a ketogenic diet, needs to be oxidized to β-hydroxybutyrate in vivo for energy supply, which is greatly influenced by glucose and lipid metabolism under the conditions of the basic disease itself. At present, ketogenic diet is not recommended for use in the prevention and treatment of myocardial ischemia or myocardial infarction, and in the treatment of diabetic cardiomyopathy or hypertension. [ABSTRACT FROM AUTHOR]

The complex pathogenesis of lung ischemia–reperfusion injury (LIRI) was examined in a murine model, focusing on the role of pyroptosis and its exacerbation of lung injury. We specifically examined the levels and cellular localization of pyroptosis within the lung, which revealed alveolar macrophages as the primary site. The inhibition of pyroptosis by VX‐765 reduced the severity of lung injury, underscoring its significant role in LIRI. Furthermore, the therapeutic potential of β‐hydroxybutyrate (β‐OHB) in ameliorating LIRI was examined. Modulation of β‐OHB levels was evaluated by ketone ester supplementation and 3‐hydroxybutyrate dehydrogenase 1 (BDH‐1) gene knockout, along with the manipulation of the SIRT1‐FOXO3 signaling pathway using EX‐527 and pCMV‐SIRT1 plasmid transfection. This revealed that β‐OHB exerts lung‐protective and anti‐pyroptotic effects, which were mediated through the upregulation of SIRT1 and the enhancement of FOXO3 deacetylation, leading to decreased pyroptosis markers and lung injury. In addition, β‐OHB treatment of MH‐S cells in vitro showed a concentration‐dependent improvement in pyroptosis, linking its therapeutic benefits to specific cell mechanisms. Overall, this study highlights the significance of alveolar macrophage pyroptosis in the exacerbation of LIRI and indicates the potential of β‐OHB in mitigating injury by modulating the SIRT1‐FOXO3 signaling pathway. [ABSTRACT FROM AUTHOR]

Aims: The aims of our study were to evaluate whether point‐of‐care β‐hydroxybutyrate (BHB) measurement can be used to identify patients with adequate cardiac glucose metabolism suppression for cardiac [18F]‐fluoro‐2‐deoxy‐d‐glucose‐positron emission tomography with computerized tomography (FDG‐PET/CT) and to develop a pretest probability calculator of myocardial suppression using other metabolic factors attainable before imaging. Methods and Results: We recruited 193 patients with any clinical indication for whole body [18F]‐FDG‐PET/CT. BHB level was measured with a point‐of‐care device. Maximal myocardial standardized uptake value using lean body mass (SULmax) was measured from eight circular regions of interest with 1 cm circumference and background from left ventricular blood pool. Correlations SULmax and point‐of‐care measured BHB were analysed. The ability of BHB test to predict adequate suppression was evaluated with receiver operating characteristic analysis. Liver and spleen attenuation in computed tomography were measured to assess the presence of fatty liver. BHB level correlated with myocardial uptake and, using a cut‐off value of 0.35 mmol/L to predict adequate myocardial suppression, we reached specificity of 90% and sensitivity of 56%. Other variables to predict adequate suppression were diabetes, obesity, ketogenic diet and fatty liver. Using information attainable before imaging, we created a pretest probability calculator of inadequate myocardial glucose metabolism suppression. The area under the curve for BHB test alone was 0.802 and was 0.857 for the pretest calculator (p = 0.319). Conclusions: BHB level measured with a point‐of‐care device is useful in predicting adequate myocardial glucose metabolism suppression. More detailed assessment of other factors potentially contributing to cardiac metabolism is needed. [ABSTRACT FROM AUTHOR]

Abstract Exogenous ketone supplements are a potential augmentation strategy for cognitive resilience during acute hypoxic exposure due to their capacity to attenuate the decline in oxygen (O2) availability, and by providing an alternative substrate for cerebral metabolism. Utilizing a single‐blind randomized crossover design, 16 male military personnel (age, 25.3 ± 2.4 year, body mass, 86.2 ± 9.3 kg) performed tests of cognitive performance at rest in three environments: room air (baseline), normoxia (20 min; 0 m; 20.9% O2) and hypoxia (20 min; 6096 m, 9.7% O2) using a reduced O2 breathing device (ROBD). (R)‐3‐Hydroxybutyl (R)‐3‐hydroxybutyrate (R‐BD R‐βHB) ketone monoester (KME; 650 mg/kg, split dose given at 30 min prior to each exposure) or taste‐matched placebo (PLA) was ingested prior to normoxia and hypoxic exposure. Blood R‐βHB and glucose concentrations, cognitive performance and O2 saturation (SpO2) were collected throughout. KME ingestion increased blood R‐βHB concentration, which was rapid and sustained (>4 mM 30 min post; P

Abstract Acute ingestion of exogenous ketone supplements in the form of a (R)‐3‐hydroxybutyl (R)‐3‐hydroxybutyrate (R‐BD R‐βHB) ketone monoester (KME) can attenuate declines in oxygen availability during hypoxic exposure and might impact cognitive performance at rest and in response to moderate‐intensity exercise. In a single‐blind randomized crossover design, 16 males performed assessments of cognitive performance before and during hypoxic exposure with moderate exercise [2 × 20 min weighted ruck (∼22 kg) at 3.2 km/h at 10% incline] in a normobaric altitude chamber (4572 m, 11.8% O2). The R‐BD R‐βHB KME (573 mg/kg) or a calorie‐ and taste‐matched placebo (∼50 g maltodextrin) were co‐ingested with 40 g of dextrose before exposure to hypoxia. The R‐βHB concentrations were rapidly elevated and sustained (>3 mM; P

Cisplatin is a particularly potent antineoplastic drug. However, its usefulness is restricted due to the induction of nephrotoxicity. More recent research has indicated that β-hydroxybutyrate (β-HB) protects against acute or chronic organ damage as an efficient healing agent. Nonetheless, the therapeutic mechanisms of β-HB in acute kidney damage caused by chemotherapeutic drugs remain unclear. Our study developed a model of cisplatin-induced acute kidney injury (AKI), which involved the administration of a ketogenic diet or β-HB. We analyzed blood urea nitrogen (BUN) and creatinine (Cr) levels in serum, and used western blotting and immunohistochemical staining to assess ferroptosis and the calcium/calmodulin-dependent kinase kinase 2 (Camkk2)/AMPK pathway. The mitochondrial morphology and function were examined. Additionally, we conducted in vivo and in vitro experiments using selective Camkk2 inhibitor or activator to investigate the protective mechanism of β-HB on cisplatin-induced AKI. Exogenous or endogenous β-HB effectively alleviated cisplatin-induced abnormally elevated levels of BUN and Cr and renal tubular necrosis in vivo. Additionally, β-HB reduced ferroptosis biomarkers and increased the levels of anti-ferroptosis biomarkers in the kidney. β-HB also improved mitochondrial morphology and function. Moreover, β-HB significantly attenuated cisplatin-induced cell ferroptosis and damage in vitro. Furthermore, western blotting and immunohistochemical staining indicated that β-HB may prevent kidney injury by regulating the Camkk2-AMPK pathway. The use of the Camkk2 inhibitor or activator verified the involvement of Camkk2 in the renal protection by β-HB. This study provided evidence of the protective effects of β-HB against cisplatin-induced nephrotoxicity and identified inhibited ferroptosis and Camkk2 as potential molecular mechanisms. Cisplatin induces disruptions in mitochondrial energy metabolism and lipid peroxidation. Both endogenous and exogenous β-hydroxybutyrate can protected against cisplatin-induced renal damage by repairing mitochondrial energy homeostasis and preventing ferroptosis, and this protective effect might be attributed to Camkk2 regulation. β-HB protects against cisplatin-induced renal damage both in vivo and in vitro. Moreover, β-HB is effective in attenuating cisplatin-induced lipid peroxidation and ferroptosis. The regulation of energy metabolism, as well as the treatment involving β-HB, is associated with Camkk2. [ABSTRACT FROM AUTHOR]

Abstract Stroke is a significant global burden, causing extensive morbidity and mortality. In metabolic states where glucose is limited, ketone bodies, predominantly β-hydroxybutyrate (BHB), act as alternative fuel sources. Elevated levels of BHB have been found in the ischemic hemispheres of animal models of stroke, supporting its role in the pathophysiology of cerebral ischemia. Clinically, higher serum and urinary BHB concentrations have been associated with adverse outcomes in ischemic stroke, highlighting its potential utility as a prognostic biomarker. In both animal and cellular models, exogenous BHB administration has exhibited neuroprotective effects, reduction of infarct size, and improvement of neurological outcomes. In this review, we focus on the role of BHB before and after ischemic stroke, with an emphasis on the therapeutic potential and mechanisms of ketone administration after ischemic stroke.

Abstract Background Ketone β-hydroxybutyrate (BHB) has been reported to prevent tumor cell proliferation and improve drug resistance. However, the effectiveness of BHB in oxaliplatin (Oxa)-resistant colorectal cancer (CRC) and the underlying mechanism still require further proof. Methods CRC-Oxa-resistant strains were established by increasing concentrations of CRC cells to Oxa. CRC-Oxa cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) were checked following BHB intervention in vitro. The subcutaneous and metastasis models were established to assess the effects of BHB on the growth and metastasis of CRC-Oxa in vivo. Eight Oxa responders and seven nonresponders with CRC were enrolled in the study. Then, the serum BHB level and H3K79me, H3K27ac, H3K14ac, and H3K9me levels in tissues were detected. DOT1L (H3K79me methyltransferase) gene knockdown or GNE-049 (H3K27ac inhibitor) use was applied to analyze further whether BHB reversed CRC-Oxa resistance via H3K79 demethylation and/or H3K27 deacetylation in vivo and in vitro. Results Following BHB intervention based on Oxa, the proliferation, migration, invasion, and EMT of CRC-Oxa cells and the growth and metastasis of transplanted tumors in mice were suppressed. Clinical analysis revealed that the differential change in BHB level was associated with drug resistance and was decreased in drug-resistant patient serum. The H3K79me, H3K27ac, and H3K14ac expressions in CRC were negatively correlated with BHB. Furthermore, results indicated that H3K79me inhibition may lead to BHB target deletion, resulting in its inability to function. Conclusions β-hydroxybutyrate resensitized CRC cells to Oxa by suppressing H3K79 methylation in vitro and in vivo.

The objective of this study was to examine the effect of consuming ketone monoester plus a high dose of carbohydrate from glucose (KE + CHO) on the change in erythropoietin (EPO) concentrations during load carriage exercise compared with carbohydrate (CHO) alone. Using a randomized, crossover design, 12 males consumed KE + CHO (573 mg KE/kg body mass, 110 g glucose) or CHO (110 g glucose) 30 min before 4 miles of self‐paced treadmill exercise (KE + CHO:51 ± 13%, CHO: 52 ± 12% V̇O2peak) wearing a weighted vest (30% body mass; 25 ± 3 kg). Blood samples for analysis were obtained under resting fasted conditions before (Baseline) consuming the KE + CHO or CHO supplement and immediately after exercise (Post). βHB increased (p < 0.05) from Baseline to Post in KE + CHO, with no change in CHO. Glucose and glycerol increased (p < 0.05) from Baseline to Post in CHO, with no effect of time in KE + CHO. Insulin and lactate increased (p < 0.05) from Baseline to Post independent of treatment. EPO increased (p < 0.05) from Baseline to Post in KE + CHO and CHO with no difference between treatments. Although KE + CHO altered βHB, glucose, and glycerol concentrations, results from this study suggest that KE + CHO supplementation before load carriage exercise does not enhance immediate post‐exercise increases in EPO compared with CHO alone. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is widely recognized as the prevailing joint disease associated with aging. The ketogenic diet (KD) has been postulated to impede the advancement of various inflammatory ailments. β‐Hydroxybutyrate (βOHB), a prominent constituent of ketone bodies, has recently been proposed to possess crucial signaling capabilities. In this study, we propose to explore the role and mechanism of βOHB in OA. Tissue staining and inflammatory factor assay were employed to evaluate the impacts of KD and βOHB on OA rats. The oxidative stress conditions in chondrocytes were induced using tert‐butyl hydroperoxide (TBHP). The mechanisms were determined using the siRNA of hydroxycarboxylic acid receptor 2 (HCAR2), the antagonist of adenosine monophosphate‐activated protein kinase (AMPK), and the inhibitor of mitophagy. The administration of KD demonstrated a reduction in pathological damage to cartilage, as well as a decrease in plasma levels of inflammatory factors. Furthermore, it resulted in an increase in the concentration of βOHB in the blood and synovial fluid. In vitro experiments showed that βOHB facilitated mitophagy and adenosine triphosphate production. Besides, βOHB mitigated chondrocyte senescence, inflammatory factors secretion, extracellular matrix degradation, and apoptosis induced by TBHP. Subsequent investigations indicated that the protective effects of βOHB were no longer observed following the knockdown of HCAR2, the antagonist of AMPK, or the inhibitor of mitophagy. Moreover, in vivo studies suggested that βOHB played a protective role by targeting the HCAR2‐AMPK‐PINK1 axis. In conclusion, βOHB enhanced chondrocyte mitophagy through the HCAR2/AMPK/PINK1/Parkin pathway, offering a potential therapeutic approach for the treatment of OA. [ABSTRACT FROM AUTHOR]

Stroke is a significant global burden, causing extensive morbidity and mortality. In metabolic states where glucose is limited, ketone bodies, predominantly β-hydroxybutyrate (BHB), act as alternative fuel sources. Elevated levels of BHB have been found in the ischemic hemispheres of animal models of stroke, supporting its role in the pathophysiology of cerebral ischemia. Clinically, higher serum and urinary BHB concentrations have been associated with adverse outcomes in ischemic stroke, highlighting its potential utility as a prognostic biomarker. In both animal and cellular models, exogenous BHB administration has exhibited neuroprotective effects, reduction of infarct size, and improvement of neurological outcomes. In this review, we focus on the role of BHB before and after ischemic stroke, with an emphasis on the therapeutic potential and mechanisms of ketone administration after ischemic stroke. [ABSTRACT FROM AUTHOR]

Sarcopenia, a leading cause for global disability and mortality, is an age‐related muscular disorder, characterized by accelerated muscle mass loss and functional decline. It is known that caloric restriction (CR), ketogenic diet or endurance exercise lessen sarcopenia and elevate circulating β‐hydroxybutyrate (β‐HB) levels. Whether the elevated β‐HB is essential to the reversal of sarcopenia, however, remains unclear. Here we show in both Caenorhabditis elegans and mouse models that an increase of β‐HB reverse myofiber atrophy and improves motor functions at advanced ages. β‐HB‐induced histone lysine β‐hydroxybutyrylation (Kbhb) is indispensable for the reversal of sarcopenia. Histone Kbhb enhances transcription of genes associated with mitochondrial pathways, including oxidative phosphorylation, ATP metabolic process and aerobic respiration. This ultimately leads to improve mitochondrial integrity and enhance mitochondrial respiration. The histone Kbhb are validated in mouse model with CR. Thus, we demonstrate that β‐HB induces histone Kbhb, increases mitochondrial function, and reverses sarcopenia. [ABSTRACT FROM AUTHOR]

Background: Alzheimer's disease is a neurological disease characterized by the build-up of amyloid beta peptide (Aβ) and lipopolysaccharide (LPS), which causes synapse dysfunction, cell death, and neuro-inflammation. A maladaptive unfolded protein response (UPR), excessive autophagy, and pyroptosis aggravate the disease. Melatonin (MEL) and hydroxybutyrate (BHB) have both shown promise in terms of decreasing Aβ pathology. The goal of this study was to see how BHB and MEL affected the UPR, autophagy, and pyroptosis pathways in Aβ1–42 and LPS-induced SH-SY5Y cells. Materials and methods: Human neuroblastoma SH-SY5Y cells were treated with BHB, MEL, or a combination of the two after being exposed to A β1–42 and LPS. Cell viability was determined using the MTT test, and gene expression levels of UPR (ATF6, PERK, and CHOP), autophagy (Beclin-1, LC3II, P62, and Atg5), and pyroptosis-related markers (NLRP3, TXNIP, IL-1β, and NFκB1) were determined using quantitative Real-Time PCR (qRT-PCR). For statistical analysis, one-way ANOVA was employed, followed by Tukey's post hoc test. Results: BHB and MEL significantly increased SH-SY5Y cell viability in the presence of A β1–42 and LPS. Both compounds inhibited the expression of maladaptive UPR and autophagy-related genes, as well as inflammatory and pyroptotic markers caused by Aβ1–42 and LPS-induced SH-SY5Y cells. Conclusion: BHB and MEL rescue neurons in A β1–42 and LPS-induced SH-SY5Y cells by reducing maladaptive UPR, excessive autophagy, and pyroptosis. More research is needed to fully comprehend the processes behind their beneficial effects and to discover their practical applications in the treatment of neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Background: Cancer stem cell phenotype confers tumor aggressiveness in multiple malignancies, including nasopharyngeal carcinoma (NPC). Many studies supported that β-hydroxybutyrate (BHB), a ketone body, acts as an epigenetic factor with an anticancer effect. Nevertheless, the effects of BHB on NPC remain elusive. Objective: This study explored whether BHB suppressed the aggressive phenotype of NPC cells by suppressing their stemness-like characteristics and exerting an anti-NPC effect. Results: The proliferation, migration, and invasion abilities of NPC cells after BHB intervention were attenuated, the protein levels of E-cadherin were downregulated, that of N-cadherin and vimentin were upregulated, the volume and number of cell spheres were reduced, and the number of CD44 + cells (cell surface stem cell marker) was reduced. Knockdown of HDAC4 abrogated the effects of BHB on cell proliferation, invasive phenotype, and stemness. The molecular docking map of BHB-HDAC4 displayed that BHB binds the catalytic domain in HDAC4, speculating that BHB functions as an HDAC4-specific inhibitor, preventing the catalytic function of HDAC4 protein rather than inhibiting the translational synthesis of HDAC4 protein. Conclusions: BHB inhibited NPC cells' proliferation, stemness characteristics, and invasive phenotypes by specifically restraining HDAC4 expression. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates are a class of biodegradable, thermoplastic polymers which represent a major carbon source for various bacteria. Proteins which mediate the translocation of polyhydroxyalkanoate breakdown products, such as β‐hydroxybutyrate (BHB)—a ketone body which in humans serves as an important biomarker, have not been well characterized. In our investigation to screen a solute‐binding protein (SBP) which can act as a suitable recognition element for BHB, we uncovered insights at the intersection of bacterial metabolism and diagnostics. Herein, we identify SBPs associated with putative ATP‐binding cassette transporters that specifically recognize BHB, with the potential to serve as recognition elements for continuous quantification of this analyte. Through bioinformatic analysis, we identified candidate SBPs from known metabolizers of polyhydroxybutyrate—including proteins from Cupriavidus necator, Ensifer meliloti, Paucimonas lemoignei, and Thermus thermophilus. After recombinant expression in Escherichia coli, we demonstrated with intrinsic tryptophan fluorescence spectroscopy that four candidate proteins interacted with BHB, ranging from nanomolar to micromolar affinity. Tt.2, an intrinsically thermostable protein from Thermus thermophilus, was observed to have the tightest binding and specificity for BHB, which was confirmed by isothermal calorimetry. Structural analyses facilitated by AlphaFold2, along with molecular docking and dynamics simulations, were used to hypothesize key residues in the binding pocket and to model the conformational dynamics of substrate unbinding. Overall, this study provides strong evidence identifying the cognate ligands of SBPs which we hypothesize to be involved in prokaryotic cellular translocation of polyhydroxyalkanoate breakdown products, while highlighting these proteins' promising biotechnological application. [ABSTRACT FROM AUTHOR]

Background: Ketone β-hydroxybutyrate (BHB) has been reported to prevent tumor cell proliferation and improve drug resistance. However, the effectiveness of BHB in oxaliplatin (Oxa)-resistant colorectal cancer (CRC) and the underlying mechanism still require further proof. Methods: CRC-Oxa-resistant strains were established by increasing concentrations of CRC cells to Oxa. CRC-Oxa cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) were checked following BHB intervention in vitro. The subcutaneous and metastasis models were established to assess the effects of BHB on the growth and metastasis of CRC-Oxa in vivo. Eight Oxa responders and seven nonresponders with CRC were enrolled in the study. Then, the serum BHB level and H3K79me, H3K27ac, H3K14ac, and H3K9me levels in tissues were detected. DOT1L (H3K79me methyltransferase) gene knockdown or GNE-049 (H3K27ac inhibitor) use was applied to analyze further whether BHB reversed CRC-Oxa resistance via H3K79 demethylation and/or H3K27 deacetylation in vivo and in vitro. Results: Following BHB intervention based on Oxa, the proliferation, migration, invasion, and EMT of CRC-Oxa cells and the growth and metastasis of transplanted tumors in mice were suppressed. Clinical analysis revealed that the differential change in BHB level was associated with drug resistance and was decreased in drug-resistant patient serum. The H3K79me, H3K27ac, and H3K14ac expressions in CRC were negatively correlated with BHB. Furthermore, results indicated that H3K79me inhibition may lead to BHB target deletion, resulting in its inability to function. Conclusions: β-hydroxybutyrate resensitized CRC cells to Oxa by suppressing H3K79 methylation in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Exogenous supplementation with ketone beverages has been shown to reduce plasma glucose levels during acute nutritional ketosis. It remains to be investigated whether growth differentiation factor 15 (GDF-15)—an anorexigenic hormone—is involved in this process. The aim was to investigate the effect of a ketone ester beverage delivering β-hydroxybutyrate (KEβHB) on plasma levels of GDF-15, as well as assess the influence of eating behaviour on it. The study was a randomised controlled trial (registered at clinicaltrials.gov as NCT03889210). Individuals were given a KEβHB beverage or placebo in a cross-over fashion. Blood samples were collected at baseline, 30, 60, 90, 120, and 150 min after ingestion. Eating behaviour was assessed using the three-factor eating questionnaire. GDF-15 levels were not significantly different (p = 0.503) after the KEβHB beverage compared with the placebo. This finding remained consistent across the cognitive restraint, emotional eating, and uncontrolled eating domains. Changes in the anorexigenic hormone GDF-15, irrespective of eating behaviour, do not appear to play a major role in the glucose-lowering effect of exogenous ketones. [ABSTRACT FROM AUTHOR]

We recently demonstrated that acute oral ketone monoester intake induces a stimulation of postprandial myofibrillar protein synthesis rates comparable to that elicited following the ingestion of 10 g whey protein or their coingestion. The present investigation aimed to determine the acute effects of ingesting a ketone monoester, whey protein, or their coingestion on mechanistic target of rapamycin (mTOR)-related protein-protein colocalization and intracellular trafficking in human skeletal muscle. In a randomized, double-blind, parallel group design, 36 healthy recreationally active young males (age: 24.2 ± 4.1 yr) ingested either: 1) 0.36 g·kg−1 bodyweight of the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (KET), 2) 10 g whey protein (PRO), or 3) the combination of both (KET + PRO). Muscle biopsies were obtained in the overnight postabsorptive state (basal conditions), and at 120 and 300 min in the postprandial period for immunofluorescence assessment of protein translocation and colocalization of mTOR-related signaling molecules. All treatments resulted in a significant (Interaction: P < 0.0001) decrease in tuberous sclerosis complex 2 (TSC2)-Ras homolog enriched in brain (Rheb) colocalization at 120 min versus basal; however, the decrease was sustained at 300 min versus basal (P < 0.0001) only in KET + PRO. PRO and KET + PRO increased (Interaction: P < 0.0001) mTOR-Rheb colocalization at 120 min versus basal; however, KET + PRO resulted in a sustained increase in mTOR-Rheb colocalization at 300 min that was greater than KET and PRO. Treatment intake increased mTOR-wheat germ agglutinin (WGA) colocalization at 120 and 300 min (Time: P = 0.0031), suggesting translocation toward the fiber periphery. These findings demonstrate that ketone monoester intake can influence the spatial mechanisms involved in the regulation of mTORC1 in human skeletal muscle. NEW & NOTEWORTHY: We explored the effects of a ketone monoester (KET), whey protein (PRO), or their coingestion (KET + PRO) on mTOR-related protein-protein colocalization and intracellular trafficking in human muscle. All treatments decreased TSC2-Rheb colocalization at 120 minutes; however, KET + PRO sustained the decrease at 300 min. Only PRO and KET + PRO increased mTOR-Rheb colocalization; however, the increase at 300 min was greater in KET + PRO. Treatment intake increased mTOR-WGA colocalization, suggesting translocation to the fiber periphery. Ketone bodies influence the spatial regulation of mTOR. [ABSTRACT FROM AUTHOR]

Ketone bodies (acetoacetate and β-hydroxybutyrate) are oxidized in skeletal muscle mainly during fasting as an alternative source of energy to glucose. Previous studies suggest that there is a negative relationship between increased muscle ketolysis and muscle glucose metabolism in mice with obesity and/or type 2 diabetes. Therefore, we investigated the connection between increased ketone body exposure and muscle glucose metabolism by measuring the effect of a 3-h exposure to ketone bodies on glucose uptake in differentiated L6 myotubes. We showed that exposure to acetoacetate at a typical concentration (0.2 mM) resulted in increased basal glucose uptake in L6 myotubes, which was dependent on increased membrane glucose transporter type 4 (GLUT4) translocation. Basal and insulin-stimulated glucose uptake was also increased with a concentration of acetoacetate reflective of diabetic ketoacidosis or a ketogenic diet (1 mM). We found that β-hydroxybutyrate had a variable effect on basal glucose uptake: a racemic mixture of the two β-hydroxybutyrate enantiomers (d and l) appeared to decrease basal glucose uptake, while 3 mM d -β-hydroxybutyrate alone increased basal glucose uptake. However, the effects of the ketone bodies individually were not observed when acetoacetate was present in combination with β-hydroxybutyrate. These results provide insight that will help elucidate the effect of ketone bodies in the context of specific metabolic diseases and nutritional states (e.g., type 2 diabetes and ketogenic diets). NEW & NOTEWORTHY: A limited number of studies investigate the effect of ketone bodies at concentrations reflective of both typical fasting and ketoacidosis. We tested a mix of physiologically relevant concentrations of ketone bodies, which allowed us to highlight the differential effects of d - and l -β-hydroxybutyrate and acetoacetate on skeletal muscle cell glucose uptake. Our findings will assist in better understanding the mechanisms that contribute to muscle insulin resistance and provide guidance on recommendations regarding ketogenic diets. [ABSTRACT FROM AUTHOR]

IntroductionSpecial Operations Forces (SOF) often conduct operations in physiologically stressful environments such as severe heat, cold, or hypoxia, which can induce decreases in a variety of cognitive abilities. Given the promising empirical demonstration of the efficacy of exogenous ketone monoester (KME) supplementation in attenuating cognitive performance decrease during hypoxia at rest in a laboratory setting, we conducted a real-world, field experiment examining KME’s efficacy during high-altitude mountaineering, an austere environment in which US SOF have conducted increasing numbers of operations over the past two decades.MethodsSpecifically, 34 students and cadre at the US Army 10th Special Forces Group Special Operations Advanced Mountaineering School (SOAMS) participated in a randomized, double-blind, placebo (PLA)–controlled crossover trial (KME vs. PLA) over 2 days of tactical mountain operations training. The participants ascended from 7,500 ft in altitude (basecamp) to 12,460 ft on 1 day and 13,627 ft the other day (in randomized order), while performing various training activities inducing high physical and cognitive loads over 8–12 h, and consumed six doses of KME or PLA 2–3 h apart throughout each training day.Results and DiscussionWhile KME increased blood ketone levels and decreased glucose levels, there were no clear indications that the elevated ketone level enhanced physical or cognitive performance. KME also produced a greater incidence of heartburn, nausea, and vomiting. In these elite operators, high-altitude mountaineering had a limited impact on cognitive performance, and KME supplementation did not demonstrate any benefit.

Stroke-related sarcopenia (SRS) is characterized by progressive systemic muscle loss and decreased function and is thought to be primarily affected by catabolic-anabolic imbalance, but there is a lack of specific treatment. Our study evaluated whether β-hydroxybutyrate (BHB) improves SRS through regulation in protein synthesis and proteolysis. BHB reduced infarct volume, increased muscle mass and muscle fiber cross-sectional area. Delayed administration of BHB, when the infarct volume was stable, improved the balance beam score and time of rotarod and the above SRS indicators. Mechanistically, BHB increased the total contents of H3K9bhb in gastrocnemius muscles of tMCAO mice and enhanced the endogenous binding of H3K9bhb with Foxo3a promoter in response to the transcription inhibition of Foxo3a. Our study indicated BHB alleviated SRS, which was partly mediated by H3K9bhb, and then inhibited FOXO3a. BHB also promoted protein synthesis, muscle regeneration and proliferation to maintain protein metabolic homeostasis and ultimately ameliorated SRS.

Several disorders of energy metabolism have been treated with exogenous ketone bodies. The benefit of this treatment is best documented in multiple acyl-CoA dehydrogenase deficiency (MADD) (MIM#231680). One might also expect ketone bodies to help in other disorders with impaired ketogenesis or in conditions that profit from a ketogenic diet. Here, we report the use of a novel preparation of dextro-β-hydroxybutyrate (D-βHB) salts in two cases of MADD and one case of pyruvate dehydrogenase (PDH) deficiency (MIM#312170). The two patients with MADD had previously been on a racemic mixture of D- and L‑sodium hydroxybutyrate. Patient #1 found D-βHB more palatable, and the change in formulation corrected hypernatraemia in patient #2. The patient with PDH deficiency was on a ketogenic diet but had not previously been given hydroxybutyrate. In this case, the addition of D-βHB improved ketosis. We conclude that NHS101 is a good candidate for further clinical studies in this group of diseases of inborn errors of metabolism.

Abstract The classic ketogenic diet is an effective treatment option for drug-resistant epilepsy, but its high fat content challenges patient compliance. Optimizing liver ketone production guided by a method comparing substrates for their ketogenic potential may help to reduce the fat content of the diet without loss in ketosis induction. Here, we present a liver cell assay measuring the β-hydroxybutyrate (βHB) yield from fatty acid substrates. Even chain albumin-conjugated fatty acids comprising between 4 and 18 carbon atoms showed a sigmoidal concentration-βHB response curve (CRC) whereas acetate and omega-3 PUFAs produced no CRC. While CRCs were not distinguished by their half-maximal effective concentration (EC50), they differed by maximum response, which related inversely to the carbon chain length and was highest for butyrate. The assay also suitably assessed the βHB yield from fatty acid blends detecting shifts in maximum response from exchanging medium chain fatty acids for long chain fatty acids. The assay further detected a dual role for butyrate and hexanoic acid as ketogenic substrate at high concentration and ketogenic enhancer at low concentration, augmenting the βHB yield from oleic acid and a fatty acid blend. The assay also found propionate to inhibit ketogenesis from oleic acid and a fatty acid blend at low physiological concentration. Although the in vitro assay shows promise as a tool to optimize the ketogenic yield of a fat blend, its predictive value requires human validation.

Abstract Background Prostate cancer (PCa) is one of the most prevalent cancers in men and is associated with high mortality and disability rates. β-hydroxybutyrate (BHB), a ketone body, has received increasing attention for its role in cancer. However, its role in PCa remains unclear. This study aimed to explore the mechanism and feasibility of BHB as a treatment alternative for PCa. Methods Colony formation assay, flow cytometry, western blot assay, and transwell assays were performed to determine the effect of BHB on the proliferation and metastasis of PCa cells. Tumor sphere formation and aldehyde dehydrogenase assays were used to identify the impact of BHB or indoleacetamide-N-methyltransferase (INMT) on the stemness of PCa cells. N6-methyladenosine (m6A)–meRIP real-time reverse transcription polymerase chain reaction and dual luciferase assays were conducted to confirm INMT upregulation via the METTL3–m6A pathway. Co-IP assay was used to detect the epigenetic modification of INMT by BHB-mediated β-hydroxybutyrylation (kbhb) and screen enzymes that regulate INMT kbhb. Mouse xenograft experiments demonstrated the antitumor effects of BHB in vivo. Results BHB can inhibit the proliferation, migration, and invasion of PCa cells by suppressing their stemness. Mechanistically, INMT, whose expression is upregulated by the METTL3–m6A pathway, was demonstrated to be an oncogenic gene that promotes the stem-like characteristics of PCa cells. BHB can suppress the malignant phenotypes of PCa by kbhb of INMT, which in turn inhibits INMT expression. Conclusions Our findings indicate a role of BHB in PCa metabolic therapy, thereby suggesting an epigenetic therapeutic strategy to target INMT in aggressive PCa. Trial registration Not applicable.

During lactation, dairy cows undergo various metabolic changes that are reflected not only in milk yield but also in milk composition. This study aimed to determine the milk performance and composition depending on the stage of lactation and describe relationships between energy metabolism indicators (ketone bodies: β-hydroxybutyrate (BHB), acetone) in milk and selected indicators of milk performance and composition. The study was conducted on 1,909 dairy cows (Holstein, Czech Fleckvieh, and their crossbreds), which were divided into four groups according to the stage of lactation (early (6-100 days in milk), mid (101-200 days), late (201-305 days), and extended (>305 days)). The obligatory dynamics of the main milk components were found during the entire lactation, i.e., an increase in the protein content (from 3.30 to 3.76 g/100 g) and fat content (from 4.25 to 4.42 g/100 g) and a decrease in the lactose content (from 5.06 to 4.91 g/100 g). Significantly higher (P < 0.001) contents of ketone bodies were found in early and extended lactation than in mid and late lactation. The effect of lipomobilization on milk fat composition is documented by positive correlation coefficients between ketone bodies and long-chain fatty acids (FAs) and medium-chain FAs and negative correlation coefficients between ketone bodies and short-chain FAs. Positive correlation coefficients were calculated between ketone bodies and milk fat, citric acid, fat-to-protein ratio, and somatic cell score, and negative correlation coefficients were calculated between ketone bodies and milk protein, lactose, and free FAs. Our results demonstrate that currently often realized extended lactation in high-yielding dairy cows is similarly demanding as early lactation regarding energy metabolism and, thus, milk composition changes.

Ketone ingestion can alter metabolism but effects on exercise performance are unclear, particularly with regard to the impact on intermittent-intensity exercise and team-sport performance. Nine professional male rugby union players each completed two trials in a double-blind, randomized, crossover design. Participants ingested either 90 ± 9 g carbohydrate (CHO; 9% solution) or an energy matched solution containing 20 ± 2 g CHO (3% solution) and 590 mg/kg body mass β-hydroxybutyrate monoester (CHO + BHB-ME) before and during a simulated rugby union-specific match-play protocol, including repeated high-intensity, sprint and power-based performance tests. Mean time to complete the sustained high-intensity performance tests was reduced by 0.33 ± 0.41 s (2.1%) with CHO + BHB-ME (15.53 ± 0.52 s) compared with CHO (15.86 ± 0.80 s) placebo (p =.04). Mean time to complete the sprint and power-based performance tests were not different between trials. CHO + BHB-ME resulted in blood BHB concentrations that remained >2 mmol/L during exercise (p <.001). Serum lactate and glycerol concentrations were lower after CHO + BHB-ME than CHO (p <.05). Coingestion of a BHB-ME with CHO can alter fuel metabolism (attenuate circulating lactate and glycerol concentrations) and may improve high-intensity running performance during a simulated rugby match-play protocol, without improving shorter duration sprint and power-based efforts. [ABSTRACT FROM AUTHOR]

Ketosis is a prevalent metabolic disease in the peripartum period of dairy cows, that causes considerable losses in milk production. In particular, the changes in the gut microbiome influence the occurrence of cow ketosis. In this study, the hindgut microbial communities of ketotic and healthy cows were compared and analyzed using 16S rRNA sequencing. Community composition analysis reveal that the predominant phyl in both groups were Bacteroidetes and Firmicutes. At the genus level, Bifidobacterium were more abundant in healthy cows than in ketotic cows. Conversely, the ketotic group exhibited a greater abundance of Bacteroides and Treponema than the healthy group. Differential hindgut fecal bacterial taxa in healthy and ketotic cows were identified by linear discriminant analysis effect size, with increases in Treponema, Bacteroides, and Peptococcaceae and decreases in Christensenellales, Chloroflexi, and Paenibacillaceae in ketotic cows. A distance-based redundancy analysis was conducted to further explore the connection between the gut microbiome, blood β-hydroxybutyrate levels, and milk production traits. The results suggested that the hindgut microflora was significantly correlated with blood β-hydroxybutyrate concentration and somatic cell score. These results improve our understanding of rectal microbes, and may help prevent ketosis in cows.

Cisplatin is a particularly potent antineoplastic drug. However, its usefulness is restricted due to the induction of nephrotoxicity. More recent research has indicated that β-hydroxybutyrate (β-HB) protects against acute or chronic organ damage as an efficient healing agent. Nonetheless, the therapeutic mechanisms of β-HB in acute kidney damage caused by chemotherapeutic drugs remain unclear. Our study developed a model of cisplatin-induced acute kidney injury (AKI), which involved the administration of a ketogenic diet or β-HB. We analyzed blood urea nitrogen (BUN) and creatinine (Cr) levels in serum, and used western blotting and immunohistochemical staining to assess ferroptosis and the calcium/calmodulin-dependent kinase kinase 2 (Camkk2)/AMPK pathway. The mitochondrial morphology and function were examined. Additionally, we conducted in vivo and in vitro experiments using selective Camkk2 inhibitor or activator to investigate the protective mechanism of β-HB on cisplatin-induced AKI. Exogenous or endogenous β-HB effectively alleviated cisplatin-induced abnormally elevated levels of BUN and Cr and renal tubular necrosis in vivo. Additionally, β-HB reduced ferroptosis biomarkers and increased the levels of anti-ferroptosis biomarkers in the kidney. β-HB also improved mitochondrial morphology and function. Moreover, β-HB significantly attenuated cisplatin-induced cell ferroptosis and damage in vitro. Furthermore, western blotting and immunohistochemical staining indicated that β-HB may prevent kidney injury by regulating the Camkk2-AMPK pathway. The use of the Camkk2 inhibitor or activator verified the involvement of Camkk2 in the renal protection by β-HB. This study provided evidence of the protective effects of β-HB against cisplatin-induced nephrotoxicity and identified inhibited ferroptosis and Camkk2 as potential molecular mechanisms.

This perspective work by academic neonatal providers is written specifically for the audience of newborn care providers and neonatologists involved in neonatal hypoglycemia screening. Herein, we propose adding a screen for congenital hyperinsulinism (CHI) by measuring glucose and ketone (i.e., β-hydroxybutyrate (BOHB)) concentrations just prior to newborn hospital discharge and as close to 48 h after birth as possible, at the same time that the mandated state Newborn Dried Blood Spot Screen is obtained. In the proposed protocol, we do not recommend specific metabolite cutoffs, as our primary objective is to simply highlight the concept of screening for CHI in newborns to newborn caregivers. The premise for our proposed screen is based on the known effect of hyperinsulinism in suppressing ketogenesis, thereby limiting ketone production. We will briefly discuss genetic CHI, other forms of neonatal hypoglycemia, and their shared mechanisms; the mechanism of insulin regulation by functional pancreatic islet cell membrane KATP channels; adverse neurodevelopmental sequelae and brain injury due to missing or delaying the CHI diagnosis; the principles of a good screening test; how current neonatal hypoglycemia screening programs do not fulfill the criteria for being effective screening tests; and our proposed algorithm for screening for CHI in newborns. [ABSTRACT FROM AUTHOR]

Exercise promotes brain plasticity partly by stimulating increases in mature brain-derived neurotrophic factor (mBDNF), but the role of the pro-BDNF isoform in the regulation of BDNF metabolism in humans is unknown. We quantified the expression of pro-BDNF and mBDNF in human skeletal muscle and plasma at rest, after acute exercise (+/− lactate infusion), and after fasting. Pro-BDNF and mBDNF were analyzed with immunoblotting, enzyme-linked immunosorbent assay, immunohistochemistry, and quantitative polymerase chain reaction. Pro-BDNF was consistently and clearly detected in skeletal muscle (40-250 pg mg−1 dry muscle), whereas mBDNF was not. All methods showed a 4-fold greater pro-BDNF expression in type I muscle fibers compared to type II fibers. Exercise resulted in elevated plasma levels of mBDNF (55%) and pro-BDNF (20%), as well as muscle levels of pro-BDNF (∼10%, all P < 0.05). Lactate infusion during exercise induced a significantly greater increase in plasma mBDNF (115%, P < 0.05) compared to control (saline infusion), with no effect on pro-BDNF levels in plasma or muscle. A 3-day fast resulted in a small increase in plasma pro-BDNF (∼10%, P < 0.05), with no effect on mBDNF. Pro-BDNF is highly expressed in human skeletal muscle, particularly in type I fibers, and is increased after exercise. While exercising with higher lactate augmented levels of plasma mBDNF, exercise-mediated increases in circulating mBDNF likely derive partly from release and cleavage of pro-BDNF from skeletal muscle, and partly from neural and other tissues. These findings have implications for preclinical and clinical work related to a wide range of neurological disorders such as Alzheimer's, clinical depression, and amyotrophic lateral sclerosis. Graphical Abstract [ABSTRACT FROM AUTHOR]

Exogenous ketone supplements have been suggested to have potential cardiovascular benefits, but their overall effect on blood pressure is unclear. Our objective was to perform a systematic review and meta-analysis on the effects of exogenous ketone supplements on blood pressure (BP) and concomitant changes in resting heart rate (HR). Five databases were searched on January 27th, 2023, for randomized and non-randomized studies. A random-effects model meta-analysis was performed including all studies jointly and separately for acute and chronic ingestion of ketone supplements. Out of 4012 studies identified in the search, 4 acute and 6 chronic studies with n = 187 participants were included. Pooled results (n = 10) showed no change in systolic (SMD [95% CI]= −0.14 [−0.40; 0.11]; I2= 30%; p = 0.17) or diastolic BP (−0.12 [−0.30; 0.05]; I2= 0%; p = 0.69), with a potential tendency observed toward increased resting heart rate (0.17 [-0.14; 0.47]; I2= 40%; p = 0.10). Similar results for systolic and diastolic BP were observed when assessing separately the effect of acute and chronic ingestion of ketone supplements (p ≥ 0.33). Supplement dosage was found to modulate the increase in resting heart rate (0.019 ± 0.006; p = 0.013; R2=100%), suggesting that higher supplement doses lead to a higher resting heart rate. Based on currently available data, acute or prolonged ingestion of ketone supplements does not seem to modulate BP. However, a tendency for HR to increase after acute ingestion was observed, particularly with higher doses. Higher quality studies with appropriate standardized measurements are needed to confirm these results. [ABSTRACT FROM AUTHOR]

Background: Prostate cancer (PCa) is one of the most prevalent cancers in men and is associated with high mortality and disability rates. β-hydroxybutyrate (BHB), a ketone body, has received increasing attention for its role in cancer. However, its role in PCa remains unclear. This study aimed to explore the mechanism and feasibility of BHB as a treatment alternative for PCa. Methods: Colony formation assay, flow cytometry, western blot assay, and transwell assays were performed to determine the effect of BHB on the proliferation and metastasis of PCa cells. Tumor sphere formation and aldehyde dehydrogenase assays were used to identify the impact of BHB or indoleacetamide-N-methyltransferase (INMT) on the stemness of PCa cells. N6-methyladenosine (m6A)–meRIP real-time reverse transcription polymerase chain reaction and dual luciferase assays were conducted to confirm INMT upregulation via the METTL3–m6A pathway. Co-IP assay was used to detect the epigenetic modification of INMT by BHB-mediated β-hydroxybutyrylation (kbhb) and screen enzymes that regulate INMT kbhb. Mouse xenograft experiments demonstrated the antitumor effects of BHB in vivo. Results: BHB can inhibit the proliferation, migration, and invasion of PCa cells by suppressing their stemness. Mechanistically, INMT, whose expression is upregulated by the METTL3–m6A pathway, was demonstrated to be an oncogenic gene that promotes the stem-like characteristics of PCa cells. BHB can suppress the malignant phenotypes of PCa by kbhb of INMT, which in turn inhibits INMT expression. Conclusions: Our findings indicate a role of BHB in PCa metabolic therapy, thereby suggesting an epigenetic therapeutic strategy to target INMT in aggressive PCa. Trial registration: Not applicable. [ABSTRACT FROM AUTHOR]

Ulcerative colitis (UC) is a chronic relapsing inflammatory disease of the colorectal area that demonstrates a dramatically increasing incidence worldwide. This study provides novel insights into the capacity of the exogenous β-hydroxybutyrate and ketogenic diet (KD) consumption to alleviate dextran sodium sulfate (DSS)-induced UC in rats. Remarkably, both interventions attenuated disease activity and colon weight-to-length ratio, and improved macro and microstructures of the damaged colon. Importantly, both β-hydroxybutyrate and KD curbed the DSS-induced aberrant NLRP3 inflammasome activation as observed in mRNA and protein expression analysis. Additionally, inhibition of the NLRP3/NGSDMD-mediated pyroptosis was detected in response to both regimens. In parallel, these modalities attenuated caspase-1 and its associated consequences of IL-1β and IL-18 overproduction. They also mitigated apoptosis as indicated by the inactivation of caspase-3. The anti-inflammatory effects of BHB and KD were confirmed by the reported decline in the levels of inflammatory markers including MPO, NFκB, IL-6, and TNF-α. Moreover, these interventions exhibited antioxidative properties by reducing ROS production and improving antioxidative enzymes. Their effectiveness in mitigating UC was also evident in the renovation of normal intestinal epithelial barrier function, as shown by correcting the discrepancies in the levels of tight junction proteins ZO-1, OCLN, and CLDN5. Furthermore, their effects on the intestinal microbiota homeostasis were investigated. In terms of autophagy, exogenous β-hydroxybutyrate upregulated BECN-1 and downregulated p62, which may account for its superiority over KD in attenuating colonic damage. In conclusion, this study provides experimental evidence supporting the potential therapeutic use of β-hydroxybutyrate or β-hydroxybutyrate-boosting regimens in UC. [ABSTRACT FROM AUTHOR]

Our research has shown that interventions producing a state of ketosis are highly effective in rat, mouse, and cat models of polycystic kidney disease (PKD), preventing and partially reversing cyst growth and disease progression. The ketone β-hydroxybutyrate (BHB) appears to underlie this effect. In addition, we have demonstrated that naturally formed microcrystals within kidney tubules trigger a renoprotective response that facilitates tubular obstruction clearance in healthy animals but, alternatively, leads to cyst formation in PKD. The administration of citrate prevents microcrystal formation and slows PKD progression. Juvenile Cy/+ rats, a nonorthologous PKD model, were supplemented from 3 to 8 wk of age with water containing titrated BHB, citrate, or in combination to find minimal effective and optimal dosages, respectively. Adult rats were given a reduced BHB/citrate combination or equimolar control K/NaCl salts from 8 to 12 wk of age. In addition, adult rats were placed in metabolic cages following BHB, citrate, and BHB/citrate administration to determine the impact on mineral, creatinine, and citrate excretion. BHB or citrate alone effectively ameliorates disease progression in juvenile rats, decreasing markers of cystic disease and, in combination, producing a synergistic effect. BHB/citrate leads to partial disease regression in adult rats with established cystic disease, inhibiting cyst formation and kidney injury. BHB/citrate confers benefits via multiple mechanisms, increases creatinine and citrate excretion, and normalizes mineral excretion. BHB and citrate are widely available and generally recognized as safe compounds and, in combination, exhibit high promise for supporting kidney health in polycystic kidney disease. [ABSTRACT FROM AUTHOR]

Ketogenic diets (KDs), fasting, or prolonged physical activity elevate serum ketone bodies (KBs) levels, providing an alternative fuel source for the brain and other organs. However, KBs play pleiotropic roles that go beyond their role in energy production. KBs can act as signaling metabolites, influence gene expression, proteins' posttranslational modifications (PTMs), inflammation, and oxidative stress. Here, we explore the impact of KBs on mammalian cell physiology, including aging and tissue regeneration. We also concentrate on KBs and cancer, given the extensive evidence that dietary approaches inducing ketosis, including fasting- mimicking diets (FMDs) and KDs, can prevent cancer and affect tumor progression. [ABSTRACT FROM AUTHOR]

Background: Clear cell renal cell carcinoma (ccRCC) is a form of kidney cancer characterized by dysregulated angiogenesis and multidrug resistance. Hypoxia-induced tumor progression plays a crucial role in ccRCC pathogenesis. Beta-hydroxybutyrate (BHB) and quercetin (QCT) have shown potential in targeting angiogenesis and drug resistance in various cancer types. This study investigates the combined effects of BHB and QCT in hypoxia-induced Caki-1 cells. Methods: Caki-1 cells were subjected to normoxic and hypoxic conditions and treated with BHB, QCT, or a combination of both. Cell-viability was assessed using the MTT assay, and mRNA expression levels of key angiogenesis-related genes (HIF-1α/2α, VEGF, Ang-1, Ang-2, and MDR4) were quantified through real-time PCR during 24 and 48 h. Results: BHB and QCT treatments, either alone or in combination, significantly reduced cell-viability in Caki-1 cells (p < 0.05). Moreover, the combined therapy demonstrated a potential effect in downregulating the expression of angiogenesis-related genes and MDR4 in hypoxia-induced cells, with a marked reduction in HIF-1α/2α, VEGF, Ang-1, and MDR4 expression (p < 0.05). The expression of Ang-2 increases significantly in presence of BHB combined QCT treatment. Conclusion: This study highlights the promising potential of a combination therapy involving BHB and QCT in mitigating angiogenesis and MDR4 expression in hypoxia-induced ccRCC cells. These findings support further investigation into the underlying mechanisms and warrant clinical studies to evaluate the therapeutic value of this combined treatment for ccRCC patients. This research provides new insights into addressing the challenges posed by angiogenesis and drug resistance in ccRCC. [ABSTRACT FROM AUTHOR]

Abstract The objective of this study was to examine the effect of consuming ketone monoester plus a high dose of carbohydrate from glucose (KE + CHO) on the change in erythropoietin (EPO) concentrations during load carriage exercise compared with carbohydrate (CHO) alone. Using a randomized, crossover design, 12 males consumed KE + CHO (573 mg KE/kg body mass, 110 g glucose) or CHO (110 g glucose) 30 min before 4 miles of self‐paced treadmill exercise (KE + CHO:51 ± 13%, CHO: 52 ± 12% V̇O2peak) wearing a weighted vest (30% body mass; 25 ± 3 kg). Blood samples for analysis were obtained under resting fasted conditions before (Baseline) consuming the KE + CHO or CHO supplement and immediately after exercise (Post). βHB increased (p

Although β-hydroxybutyrate (BHB), one of the endogenous body ketones, possesses high bioactivities, it is rapidly consumed, metabolized, and eliminated from the body. In this study, we designed new self-assembling nanoparticles that sustainably released BHB to improve bioavailability and evaluated their efficacy in in vivo experiments using rodent animal models. Since poly(β-hydroxybutyrate) [poly(BHB)] is regarded as a polymeric prodrug that is hydrolyzed by endogenous enzymes and releases BHB in a sustained manner, our idea was to engineer hydrophobic poly(BHB) in one of the segments in the amphiphilic block copolymer, of which self-assembles in water to form nanoparticles of tens of nanometers in size (abbreviated as NanoBHB). Here, methoxy-poly(ethylene glycol) was employed as the hydrophilic segment of the block copolymer to stabilize the nanoparticles in aqueous environments, thus enabling NanoBHBs to be administrable both orally and through injection. Experimental results showed that NanoBHB has low toxicity and releases free BHB for an extended period in vitro and in vivo. Moreover, NanoBHB exhibits superior nephroprotective effects in cisplatin-induced acute kidney injury mouse models compared to low-molecular-weight (LMW) sodium BHB, suggesting the potential of NanoBHB as a sustainable release formulation to supply BHB for medicinal applications.

The gut microbiota has been reported to be perturbed by chemotherapeutic agents and to modulate side effects. However, the critical role of β-hydroxybutyrate (BHB) in the regulation of the gut microbiota and the pathogenesis of chemotherapeutic agents related nephrotoxicity remains unknown. We conducted a comparative analysis of the composition and function of gut microbiota in healthy, cisplatin-challenged, BHB-treated, and high-fat diet-treated mice using 16 S rDNA gene sequencing. To understand the crucial involvement of intestinal flora in BHB's regulation of cisplatin -induced nephrotoxicity, we administered antibiotics to deplete the gut microbiota and performed fecal microbiota transplantation (FMT) before cisplatin administration. 16 S rDNA gene sequencing analysis demonstrated that both endogenous and exogenous BHB restored gut microbiota dysbiosis and cisplatin-induced intestinal barrier disruption in mice. Additionally, our findings suggested that the LPS/TLR4/NF-κB pathway was responsible for triggering renal inflammation in the gut-kidney axis. Furthermore, the ablation of the gut microbiota ablation using antibiotics eliminated the renoprotective effects of BHB against cisplatin-induced acute kidney injury. FMT also confirmed that administration of BHB-treated gut microbiota provided protection against cisplatin-induced nephrotoxicity. This study elucidated the mechanism by which BHB affects the gut microbiota mediation of cisplatin-induced nephrotoxicity by inhibiting the inflammatory response, which may help develop novel therapeutic approaches that target the composition of the microbiota.

Alopecia areata (AA) is an autoimmune inflammatory disease characterized by non‐scarring hair loss due to an immune response that targets hair follicles. The current treatment approach for AA involves the use of immunosuppressants and immunomodulators to reduce cytokine levels around affected hair follicles. Sodium‐glucose cotransporter 2 (SGLT2) inhibitors have emerged as potential anti‐inflammatory agents with diverse beneficial effects in various medical conditions. This study investigates the role of beta‐hydroxybutyrate (BHB), a ketone body produced during SGLT2 inhibition, in the pathogenesis of AA. Serum BHB levels were found to be significantly elevated in patients with AA compared with healthy controls, with higher levels correlating with severity of hair loss. BHB treatment increased inflammatory cytokine production in outer root sheath (ORS) cells, mimicking the inflammatory conditions seen in AA. The results suggest that elevated BHB levels may exacerbate the inflammatory immune response in AA patients and may be associated with chronic hair loss and resistance to treatment. Serum BHB levels may serve as a potential marker of poor prognosis in patients with severe AA. Further research is needed to elucidate the precise role of BHB in the pathogenesis of AA and its implications for disease management. [ABSTRACT FROM AUTHOR]