Therapeutic Potential of Ketone Bodies for Patients With Cardiovascular Disease: JACC State-of-the-Art Review

Long-term use of investigational β-Hydroxybutyrate salts in children with multiple acyl-CoA dehydrogenase or pyruvate dehydrogenase deficiency

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.

Association patterns of ketone bodies with the risk of adverse outcomes according to diabetes status

AIM

To investigate the associations between ketone bodies (KB) and multiple adverse outcomes including cardiovascular disease (CVD), chronic kidney disease (CKD) and all-cause mortality according to diabetes status.

METHODS

This prospective study included 222 824 participants free from CVD and CKD at baseline from the UK Biobank. Total KB including β-hydroxybutyrate, acetoacetate and acetone were measured by nuclear magnetic resonance. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between KB and adverse outcomes among participants with normoglycaemia, prediabetes and type 2 diabetes, respectively.

RESULTS

During a mean follow-up of 14.1 years, 24 088 incident CVD events (including 17 303 coronary heart disease events, 5172 stroke events and 5881 heart failure [HF] events), 8605 CKD events and 15 813 deaths, were documented. Higher total KB significantly increased the risk of HF among participants with normoglycaemia (HR, 1.32 [95% CI, 1.17-1.49], per 10-fold increase in total KB) and prediabetes (1.35 [1.04-1.76]), and increased the risk of CKD among those with normoglycaemia (1.20 [1.09-1.33]). Elevated KB levels were associated with an increased risk of all-cause mortality across the glycaemic spectrum (1.32 [1.23-1.42] for normoglycaemia, 1.45 [1.24-1.71] for prediabetes and 1.47 [1.11-1.94] for diabetes). Moreover, a significant additive interaction between KB and diabetes status was observed on the risk of death (P = .009), with 4.9% of deaths attributed to the interactive effects.

CONCLUSIONS

Our study underscored the variation in association patterns between KB and adverse outcomes according to diabetes status and suggested that KB could interact with diabetes status in an additive manner to increase the risk of mortality.

Are Sodium-Glucose Cotransporter-2 Inhibitors the Cherry on Top of Cardio-Oncology Care?

The increasing aging of the population combined with improvements in cancer detection and care has significantly improved the survival and quality of life of cancer patients. These benefits are hampered by the increase of cardiovascular diseases being heart failure the most frequent manifestation of cardiotoxicity and becoming the major cause of morbidity and mortality among cancer survivor. Current strategies to prevent cardiotoxicity involves different approaches such as optimal management of CV risk factors, use of statins and/or neurohormonal medications, and, in some cases, even the use of chelating agents. As a class, SGLT2-i have revolutionized the therapeutic horizon of HF patients independently of their ejection fraction or glycemic status. There is an abundance of data from translational and observational clinical studies supporting a potential beneficial role of SGLT2-i in mitigating the cardiotoxic effects of cancer patients receiving anthracyclines. These findings underscore the need for more robust clinical trials to investigate the effect on cardiovascular outcomes of the prophylactic SGLT2-i treatment in patients undergoing cancer treatment.

Relationships Between Changes in Serum Ketone Body Levels and Metabolic Effects in Patients with Severe Obesity Who Underwent Laparoscopic Sleeve Gastrectomy

BACKGROUND

Serum ketone bodies increase due to dynamic changes in the lipid metabolisms of patients undergoing bariatric surgery. However, there have been few studies on the role of ketone bodies after bariatric surgery. We aimed to clarify the role of and relationship between the changes in serum ketone bodies and weight loss, as well as between those changes and the metabolic effects after laparoscopic sleeve gastrectomy (LSG).

METHODS

We recruited 52 patients with severe obesity who underwent LSG. We measured acetoacetic acid (AcAc) and β-hydroxybutyric acid (β-OHB) at the baseline, 1 month, and 6 months after LSG. Subsequently, we compared the changes in the serum ketone bodies with weight-loss effects and various metabolic parameters.

RESULTS

At 1 month after LSG, β-OHB significantly increased (p = 0.009), then significantly decreased 6 months after LSG (p = 0.002). In addition, β-OHB in patients without Type 2 diabetes (T2D) and metabolic dysfunction-associated steatohepatitis (MASH) was notably higher than in patients with T2D at 1 month after LSG (p < 0.001). In the early phase, both AcAc and β-OHB mainly had strong positive correlations with changes in T2D- and MASH-related parameters. In the middle term after LSG, changes in both AcAc and β-OHB were positively correlated with changes in lipid parameters and chronic kidney disease-related parameters.

CONCLUSION

We demonstrated that the postoperative surge of ketone bodies plays a crucial function in controlling metabolic effects after LSG. These findings suggest the cause- and consequence-related roles of ketone bodies in the metabolic benefits of bariatric surgery.

Aerobic exercise-induced HIF-1α upregulation in heart failure: exploring potential impacts on MCT1 and MPC1 regulation

BACKGROUND

The terminal stage of ischemic heart disease develops into heart failure (HF), which is characterized by hypoxia and metabolic disturbances in cardiomyocytes. The hypoxic failing heart triggers hypoxia-inducible factor-1α (HIF-1α) actions in the cells sensitized to hypoxia and induces metabolic adaptation by accumulating HIF-1α. Furthermore, soluble monocarboxylic acid transporter protein 1 (MCT1) and mitochondrial pyruvate carrier 1 (MPC1), as key nodes of metabolic adaptation, affect metabolic homeostasis in the failing rat heart. Aerobic exercise training has been reported to retard the progression of HF due to enhancing HIF-1α levels as well as MCT1 expressions, whereas the effects of exercise on MCT1 and MPC1 in HF (hypoxia) remain elusive. This research aimed to investigate the action of exercise associated with MCT1 and MPC1 on HF under hypoxia.

METHODS

The experimental rat models are composed of four study groups: sham stented (SHAM), HF sedentary (HF), HF short-term exercise trained (HF-E1), HF long-term exercise trained (HF-E2). HF was initiated via left anterior descending coronary artery ligation, the effects of exercise on the progression of HF were analyzed by ventricular ultrasound (ejection fraction, fractional shortening) and histological staining. The regulatory effects of HIF-1α on cell growth, MCT1 and MPC1 protein expression in hypoxic H9c2 cells were evaluated by HIF-1α activatort/inhibitor treatment and plasmid transfection.

RESULTS

Our results indicate the presence of severe pathological remodelling (as evidenced by deep myocardial fibrosis, increased infarct size and abnormal hypertrophy of the myocardium, etc.) and reduced cardiac function in the failing hearts of rats in the HF group compared to the SHAM group. Treadmill exercise training ameliorated myocardial infarction (MI)-induced cardiac pathological remodelling and enhanced cardiac function in HF exercise group rats, and significantly increased the expression of HIF-1α (p < 0.05), MCT1 (p < 0.01) and MPC1 (p < 0.05) proteins compared to HF group rats. Moreover, pharmacological inhibition of HIF-1α in hypoxic H9c2 cells dramatically downregulated MCT1 and MPC1 protein expression. This phenomenon is consistent with knockdown of HIF-1α at the gene level.

CONCLUSION

The findings propose that long-term aerobic exercise training, as a non- pharmacological treatment, is efficient enough to debilitate the disease process, improve the pathological phenotype, and reinstate cardiac function in HF rats. This benefit is most likely due to activation of myocardial HIF-1α and upregulation of MCT1 and MPC1.

Invited review: Ketone biology-The shifting paradigm of ketones and ketosis in the dairy cow

Ketosis is currently regarded as a major metabolic disorder of dairy cows, reflective of the animal's efforts to adapt to energy deficit while transitioning into lactation. Currently viewed as a pathology by some, ketosis is associatively implicated in milk production losses and peripartal health complications that increase the risk of early removal of cows from the herd, thus carrying economic losses for dairy farmers and jeopardizing the sustainability of the dairy industry. Despite decades of intense research in the mitigation of ketosis and its sequelae, our ability to lessen its purported effects remains limited. Moreover, the association of ketosis to reduced milk production and peripartal disease is often erratic and likely mired by concurrent potential confounders. In this review, we discuss the potential reasons for these apparent paradoxes in the light of currently available evidence, with a focus on the limitations of observational research and the necessary steps to unambiguously identify the effects of ketosis on cow health and performance via controlled randomized experimentation. A nuanced perspective is proposed that considers the dissociation of ketosis-as a disease-from healthy hyperketonemia. Furthermore, in consideration of a growing body of evidence that highlights positive roles of ketones in the mitigation of metabolic dysfunction and chronic diseases, we consider the hypothetical functions of ketones as health-promoting metabolites and ponder on their potential usefulness to enhance dairy cow health and productivity.

Genetic Mutations and Mitochondrial Redox Signaling as Modulating Factors in Hypertrophic Cardiomyopathy: A Scoping Review

Hypertrophic cardiomyopathy (HCM) is a heart condition characterized by cellular and metabolic dysfunction, with mitochondrial dysfunction playing a crucial role. Although the direct relationship between genetic mutations and mitochondrial dysfunction remains unclear, targeting mitochondrial dysfunction presents promising opportunities for treatment, as there are currently no effective treatments available for HCM. This review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews guidelines. Searches were conducted in databases such as PubMed, Embase, and Scopus up to September 2023 using "MESH terms". Bibliographic references from pertinent articles were also included. Hypertrophic cardiomyopathy (HCM) is influenced by ionic homeostasis, cardiac tissue remodeling, metabolic balance, genetic mutations, reactive oxygen species regulation, and mitochondrial dysfunction. The latter is a common factor regardless of the cause and is linked to intracellular calcium handling, energetic and oxidative stress, and HCM-induced hypertrophy. Hypertrophic cardiomyopathy treatments focus on symptom management and complication prevention. Targeted therapeutic approaches, such as improving mitochondrial bioenergetics, are being explored. This includes coenzyme Q and elamipretide therapies and metabolic strategies like therapeutic ketosis. Understanding the biomolecular, genetic, and mitochondrial mechanisms underlying HCM is crucial for developing new therapeutic modalities.

Cardiovascular Effects of Oral Ketone Ester Treatment in Patients With Heart Failure With Reduced Ejection Fraction: A Randomized, Controlled, Double-Blind Trial

BACKGROUND

Heart failure triggers a shift in myocardial metabolic substrate utilization, favoring the ketone body 3-hydroxybutyrate as energy source. We hypothesized that 14-day treatment with ketone ester (KE) would improve resting and exercise hemodynamics and exercise capacity in patients with heart failure with reduced ejection fraction.

METHODS

In a randomized, double-blind cross-over study, nondiabetic patients with heart failure with reduced ejection fraction received 14-day KE and 14-day isocaloric non-KE comparator regimens of 4 daily doses separated by a 14-day washout period. After each treatment period, participants underwent right heart catheterization, echocardiography, and blood sampling at plasma trough levels and after dosing. Participants underwent an exercise hemodynamic assessment after a second dosing. The primary end point was resting cardiac output (CO). Secondary end points included resting and exercise pulmonary capillary wedge pressure and peak exercise CO and metabolic equivalents.

RESULTS

We included 24 patients with heart failure with reduced ejection fraction (17 men; 65±9 years of age; all White). Resting CO at trough levels was higher after KE compared with isocaloric comparator (5.2±1.1 L/min versus 5.0±1.1 L/min; difference, 0.3 L/min [95% CI, 0.1-0.5), and pulmonary capillary wedge pressure was lower (8±3 mm Hg versus 11±3 mm Hg; difference, -2 mm Hg [95% CI, -4 to -1]). These changes were amplified after KE dosing. Across all exercise intensities, KE treatment was associated with lower mean exercise pulmonary capillary wedge pressure (-3 mm Hg [95% CI, -5 to -1] ) and higher mean CO (0.5 L/min [95% CI, 0.1-0.8]), significantly different at low to moderate steady-state exercise but not at peak. Metabolic equivalents remained similar between treatments. In exploratory analyses, KE treatment was associated with 18% lower NT-proBNP (N-terminal pro-B-type natriuretic peptide; difference, -98 ng/L [95% CI, -185 to -23]), higher left ventricular ejection fraction (37±5 versus 34±5%; P=0.01), and lower left atrial and ventricular volumes.

CONCLUSIONS

KE treatment for 14 days was associated with higher CO at rest and lower filling pressures, cardiac volumes, and NT-proBNP levels compared with isocaloric comparator. These changes persisted during exercise and were achieved on top of optimal medical therapy. Sustained modulation of circulating ketone bodies is a potential treatment principle in patients with heart failure with reduced ejection fraction.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05161650.

Diabetes and aortic dissection: unraveling the role of 3-hydroxybutyrate through mendelian randomization

BACKGROUND

In observational and experimental studies, diabetes has been reported as a protective factor for aortic dissection. 3-Hydroxybutyrate, a key constituent of ketone bodies, has been found to favor improvements in cardiovascular disease. However, whether the protective effect of diabetes on aortic dissection is mediated by 3-hydroxybutyrate is unclear. We aimed to investigate the causal effects of diabetes on the risk of aortic dissection and the mediating role of 3-hydroxybutyrate in them through two-step Mendelian randomization.

MATERIALS AND METHODS

We performed a two-step Mendelian randomization to investigate the causal connections between diabetes, 3-hydroxybutyrate, and aortic dissection and calculate the mediating effect of 3-hydroxybutyrate. Publicly accessible data for Type 1 diabetes, Type 2 diabetes, dissection of aorta and 3-hydroxybutyrate were obtained from genome-wide association studies. The association between Type 1 diabetes and dissection of aorta, the association between Type 2 diabetes and dissection of aorta, and mediation effect of 3-hydroxybutyrate were carried out separately.

RESULTS

The IVW method showed that Type 1 diabetes was negatively associated with the risk of aortic dissection (OR 0.912, 95% CI 0.836-0.995), The weighted median, simple mode and weighted mode method showed consistent results. The mediated proportion of 3-hydroxybutyrate on the relationship between Type 1 diabetes and dissection of aorta was 24.80% (95% CI 5.12-44.47%). The IVW method showed that Type 2 diabetes was negatively associated with the risk of aortic dissection (OR 0.763, 95% CI 0.607-0.960), The weighted median, simple mode and weighted mode method showed consistent results. 3-Hydroxybutyrate does not have causal mediation effect on the relationship between Type 2 diabetes and dissection of aorta.

CONCLUSION

Mendelian randomization study revealed diabetes as a protective factor for dissection of aorta. The protective effect of type 1 diabetes on aortic dissection was partially mediated by 3-hydroxybutyrate, but type 2 diabetes was not 3-hydroxybutyrate mediated.

Daily consumption of ketone ester, bis-octanoyl (R)-1,3-butanediol, is safe and tolerable in healthy older adults, a randomized, parallel arm, double-blind, placebo-controlled, pilot study

Objectives

Ketone bodies are endogenous metabolites produced during fasting or a ketogenic diet that have pleiotropic effects on aging pathways. Ketone esters (KEs) are compounds that induce ketosis without dietary changes, but KEs have not been studied in an older adult population. The primary objective of this trial was to determine tolerability and safety of KE ingestion in older adults.

Design

Randomized, placebo-controlled, double-blinded, parallel-arm trial, with a 12-week intervention period ( NCT05585762 ).

Setting

General community, Northern California, USA.

Participants

Community-dwelling older adults, independent in activities of daily living, with no unstable acute medical conditions (n=30) were randomized and n=23 (M= 14, F=9) completed the protocol.

Intervention

Participants were randomly allocated to consume either KE (bis-octanoyl (R)-1,3-butanediol) or a taste, appearance, and calorie-matched placebo (PLA) containing canola oil.

Measurements

Tolerability was assessed using a composite score from a daily log for 2-weeks, and then via a bi-weekly phone interview. Safety was assessed by vital signs and lab tests at screening and weeks 0, 4 and 12, along with tabulation of adverse events.

Results

There was no difference in the prespecified primary outcome of proportion of participants reporting moderate or severe nausea, headache, or dizziness on more than one day in a two-week reporting period (KE n =2 (14.3% [90% CI = 2.6 - 38.5]); PLA n=1 (7.1% [90% CI = 0.4 - 29.7]). Dropouts numbered four in the PLA group and two in the KE group. A greater number of symptoms were reported in both groups during the first two weeks; symptoms were reported less frequently between 2 - 12 weeks. There were no clinically relevant changes in safety labs or vital signs in either group.

Conclusions

This KE was safe and well-tolerated in healthy older adults. These results provide a foundation for use of KEs in aging research.

Highlights

Ketones esters induce ketosis without dietary changes and may target aging biologyStudies of ketone esters were limited in duration and focused on younger adultsWe found ketone esters were safe and tolerable for 12 weeks in healthy older adults.

The ketogenic diet does not improve cardiac function and blunts glucose oxidation in ischemic heart failure

AIMS

Cardiac energy metabolism is perturbed in ischemic heart failure and is characterized by a shift from mitochondrial oxidative metabolism to glycolysis. Notably, the failing heart relies more on ketones for energy than a healthy heart, an adaptive mechanism that improves the energy-starved status of the failing heart. However, whether this can be implemented therapeutically remains unknown. Therefore, our aim was to determine if increasing ketone delivery to the heart via a ketogenic diet can improve the outcomes of heart failure.

METHODS

C57BL/6J male mice underwent either a sham surgery or permanent left anterior descending (LAD) coronary artery ligation surgery to induce heart failure. After 2 weeks, mice were then treated with either a control diet or a ketogenic diet for 3 weeks. Transthoracic echocardiography was then carried out to assess in vivo cardiac function and structure. Finally, isolated working hearts from these mice were perfused with appropriately 3H or 14C labelled glucose (5 mM), palmitate (0.8 mM), and ß-hydroxybutyrate (0.6 mM) to assess mitochondrial oxidative metabolism and glycolysis.

RESULTS

Mice with heart failure exhibited a 56% drop in ejection fraction which was not improved with a ketogenic diet feeding. Interestingly, mice fed a ketogenic diet had marked decreases in cardiac glucose oxidation rates. Despite increasing blood ketone levels, cardiac ketone oxidation rates did not increase, probably due to a decreased expression of key ketone oxidation enzymes. Furthermore, in mice on the ketogenic diet no increase in overall cardiac energy production was observed, and instead there was a shift to an increased reliance on fatty acid oxidation as a source of cardiac energy production. This resulted in a decrease in cardiac efficiency in heart failure mice fed a ketogenic diet.

CONCLUSIONS

We conclude that the ketogenic diet does not improve heart function in failing hearts, due to ketogenic diet-induced excessive fatty acid oxidation in the ischemic heart and a decrease in insulin-stimulated glucose oxidation.

Ketone body levels and its associations with cardiac markers following an acute myocardial infarction: a post hoc analysis of the EMMY trial

BACKGROUND

Sodium-glucose co-transporter 2 inhibitors (SGLT2i) have been suggested to exert cardioprotective effects in patients with heart failure, possibly by improving the metabolism of ketone bodies in the myocardium.

METHODS

This post hoc analysis of the EMMY trial investigated the changes in serum β-hydroxybutyrate (3-βOHB) levels after acute myocardial infarction (AMI) in response to 26-week of Empagliflozin therapy compared to the usual post-MI treatment. In addition, the association of baseline and repeated measurements of 3-βOHB with cardiac parameters and the interaction effects of Empagliflozin were investigated. Cardiac parameters included N-terminal pro-B-type natriuretic peptide (NT-proBNP), left ventricular ejection fraction (LVEF), left ventricle end-systolic volume (LVESV), left ventricle end-diastolic volume (LVEDV), and left ventricular filling pressure (E/é ratio).

RESULTS

The mean 3-βOHB levels increased from baseline (46.2 ± 3.0 vs. 51.7 ± 2.7) to 6 weeks (48.8 ± 2.2 vs. 42.0 ± 2.3) and 26 weeks (49.3 ± 2.2 vs. 35.8 ± 1.9) in the Empagliflozin group compared to a consistent decline in placebo over 26 weeks (pinteraction < 0.001). Baseline and longitudinal measurements of 3-βOHB were not significantly associated with NT-proBNP and E/é ratio. Baseline 3-βOHB value was negatively associated with LVEF (coefficient: - 0.464, 95%CI - 0.863;- 0.065, p = 0.023), while an increase in its levels over time was positively associated with LVEF (0.595, 0.156;1.035, 0.008). The baseline 3-βOHB was positively associated with LVESV (1.409, 0.186;2.632, 0.024) and LVEDV (0.640, - 1.170;- 2.449, 0.488), while an increase in its levels over time was negatively associated with these cardiac parameters (LVESV: - 2.099, - 3.443;- 0.755, 0.002; LVEDV: - 2.406, - 4.341;- 0.472, 0.015). Empagliflozin therapy appears to modify the association between 3-βOHB, LVEF (pinteraction = 0.090), LVESV (pinteraction = 0.134), and LVEDV (pinteraction = 0.168), particularly at 26 weeks; however, the results were not statistically significant.

CONCLUSION

This post hoc analysis showed that SGLT2i increased 3-βOHB levels after AMI compared to placebo. Higher baseline 3-βOHB levels were inversely associated with cardiac function at follow-up, whereas a sustained increase in 3-βOHB levels over time improved these markers. This highlights the importance of investigating ketone body metabolism in different post-MI phases. Although more pronounced effect of 3-βOHB on cardiac markers was observed in the SGLT2i group, further research is required to explore this interaction effect.

Dietary Influence on Drug Efficacy: A Comprehensive Review of Ketogenic Diet-Pharmacotherapy Interactions

It is widely acknowledged that the ketogenic diet (KD) has positive physiological effects as well as therapeutic benefits, particularly in the treatment of chronic diseases. Maintaining nutritional ketosis is of utmost importance in the KD, as it provides numerous health advantages such as an enhanced lipid profile, heightened insulin sensitivity, decreased blood glucose levels, and the modulation of diverse neurotransmitters. Nevertheless, the integration of the KD with pharmacotherapeutic regimens necessitates careful consideration. Due to changes in their absorption, distribution, metabolism, or elimination, the KD can impact the pharmacokinetics of various medications, including anti-diabetic, anti-epileptic, and cardiovascular drugs. Furthermore, the KD, which is characterised by the intake of meals rich in fats, has the potential to impact the pharmacokinetics of specific medications with high lipophilicity, hence enhancing their absorption and bioavailability. However, the pharmacodynamic aspects of the KD, in conjunction with various pharmaceutical interventions, can provide either advantageous or detrimental synergistic outcomes. Therefore, it is important to consider the pharmacokinetic and pharmacodynamic interactions that may arise between the KD and various drugs. This assessment is essential not only for ensuring patients' compliance with treatment but also for optimising the overall therapeutic outcome, particularly by mitigating adverse reactions. This highlights the significance and necessity of tailoring pharmacological and dietetic therapies in order to enhance the effectiveness and safety of this comprehensive approach to managing chronic diseases.

Effect of ketogenic diet on blood pressure: A GRADE-Assessed systematic review and meta-analysis of randomized controlled trials

AIMS

Cardiovascular diseases (CVDs) are major causes of mortality around the world. High blood pressure (BP) or hypertension is one of the most significant predisposing factors to CVDs. Ketogenic diets (KDs) have been the center of attention for their possible health benefits. The aim of this analysis is to study the impact of KDs on BP through the existing literature.

DATA SYNTHESIS

We investigated the impact of KDs on systolic and diastolic blood pressures (SBP and DBP) conducted in the format of randomized controlled trials (RCTs). Four online databases (PubMed/Medline, SCOPUS, Cochrane Library, and Google Scholar) were searched from inception up to November 2022. Subgroup analyses were carried out to find the sources of heterogeneities. Twenty-three RCTs with 1664 participants were identified. KDs did not exert any significant impacts on SBP (WMD: -0.87 mmHg, 95% CI: -2.05, 0.31) nor DBP (WMD: -0.11 mmHg, 95% CI -1.14, 0.93). Subgroup analyses did not reveal any further information. Also, non-linear dose-response analysis could not detect any associations between the percentage of calorie intake from fat in the KD format and BP levels.

CONCLUSION

KDs do not seem to be effective in improving BP. Nonetheless, further investigations are recommended to examine the proportion of fat intake needed to induce favorable clinical impacts.

Genome-wide characterization of circulating metabolic biomarkers

Genome-wide association analyses using high-throughput metabolomics platforms have led to novel insights into the biology of human metabolism1-7. This detailed knowledge of the genetic determinants of systemic metabolism has been pivotal for uncovering how genetic pathways influence biological mechanisms and complex diseases8-11. Here we present a genome-wide association study for 233 circulating metabolic traits quantified by nuclear magnetic resonance spectroscopy in up to 136,016 participants from 33 cohorts. We identify more than 400 independent loci and assign probable causal genes at two-thirds of these using manual curation of plausible biological candidates. We highlight the importance of sample and participant characteristics that can have significant effects on genetic associations. We use detailed metabolic profiling of lipoprotein- and lipid-associated variants to better characterize how known lipid loci and novel loci affect lipoprotein metabolism at a granular level. We demonstrate the translational utility of comprehensively phenotyped molecular data, characterizing the metabolic associations of intrahepatic cholestasis of pregnancy. Finally, we observe substantial genetic pleiotropy for multiple metabolic pathways and illustrate the importance of careful instrument selection in Mendelian randomization analysis, revealing a putative causal relationship between acetone and hypertension. Our publicly available results provide a foundational resource for the community to examine the role of metabolism across diverse diseases.

Levels of Circulating Ketone Bodies in Patients Undergoing Cardiac Surgery on Cardiopulmonary Bypass

Ketone bodies (KBs) are energy-efficient substrates utilized by the heart depending on its metabolic demand and substrate availability. Levels of circulating KBs have been shown to be elevated in acute and chronic cardiovascular disease and are associated with severity of disease in patients with heart failure and functional outcome after myocardial infarction. To investigate whether this pattern similarly applies to patients undergoing cardiac surgery involving cardiopulmonary bypass (CPB), we analysed prospectively collected pre- and postoperative blood samples from 192 cardiac surgery patients and compared levels and perioperative changes in total KBs with Troponin T as a marker of myocardial cell injury. We explored the association of patient characteristics and comorbidities for each of the two biomarkers separately and comparatively. Median levels of KBs decreased significantly over the perioperative period and inversely correlated with changes observed for Troponin T. Associations of patient characteristics with ketone body perioperative course showed notable differences compared to Troponin T, possibly highlighting factors acting as a "driver" for the change in the respective biomarker. We found an inverse correlation between perioperative change in ketone body levels and changes in troponin, indicating a marked decrease in ketone body concentrations in patients exhibiting greater myocardial cell injury. Further investigations aimed at better understanding the role of KBs on perioperative changes are warranted.

Prognosis of patients with extreme acidosis on admission to the emergency department: A retrospective cohort study

AIM OF THE STUDY

The development of acidosis in critically ill patients is considered to be a negative prognostic factor, and when extreme, even incompatible with life. We aimed to test the prognosis of patients with a pH lower than 6.9 on emergency department admission.

METHODS

A retrospective cohort study in adult patients admitted to two emergency departments with a pH < 6.9 during the first 12 h of admission. Primary outcome was mortality within 24 h from emergency department admission. We performed a regression analysis of clinical and laboratory data in order to identify factors associated with mortality in this population.

RESULTS

We analyzed data of 206 admissions to the emergency departments between 2008 and 2018 with extreme acidosis. pH Values ranged from 6.898 to 6.35 (mean 6.8 and median 6.83). 60 (29%) of the patients survived the first 24 h. 35 patients (58%) of those also survived to hospital discharge, and of them 80% have returned to their previous functional status. Patient's age, type of acidosis, cardio-pulmonary resuscitation on arrival, and diagnosis on admission were correlated with survival.

CONCLUSIONS

A small but significant portion of patients with extreme acidosis on emergency department admission survive at least to 24 h and until hospital discharge. The clinical decision making should be based on other prognostic factors rather than pH value by itself.

The therapeutic potential of ketones in cardiometabolic disease: impact on heart and skeletal muscle

β-Hydroxybutyrate (βOHB) is the major ketone in the body, and it is recognized as a metabolic energy source and an important signaling molecule. While ketone oxidation is essential in the brain during prolonged fasting/starvation, other organs such as skeletal muscle and the heart also use ketones as metabolic substrates. Additionally, βOHB-mediated molecular signaling events occur in heart and skeletal muscle cells, and via metabolism and/or signaling, ketones may contribute to optimal skeletal muscle health and cardiac function. Of importance, when the use of ketones for ATP production and/or as signaling molecules becomes disturbed in the presence of underlying obesity, type 2 diabetes, and/or cardiovascular diseases, these changes may contribute to cardiometabolic disease. As a result of these disturbances in cardiometabolic disease, multiple approaches have been used to elevate circulating ketones with the goal of optimizing either ketone metabolism or ketone-mediated signaling. These approaches have produced significant improvements in heart and skeletal muscle during cardiometabolic disease with a wide range of benefits that include improved metabolism, weight loss, better glycemic control, improved cardiac and vascular function, as well as reduced inflammation and oxidative stress. Herein, we present the evidence that indicates that ketone therapy could be used as an approach to help treat cardiometabolic diseases by targeting cardiac and skeletal muscles.

Circulating ketone bodies and mortality in heart failure: a community cohort study

Background

The relationship between ketone bodies (KB) and mortality in patients with heart failure (HF) syndrome has not been well established.

Objectives

The aim of this study is to assess the distribution of KB in HF, identify clinical correlates, and examine the associations between plasma KB and all-cause mortality in a population-based HF cohort.

Methods

The plasma KB levels were measured by nuclear magnetic resonance spectroscopy. Multivariable linear regression was used to examine associations between clinical correlates and KB levels. Proportional hazard regression was employed to examine associations between KB (represented as both continuous and categorical variables) and mortality, with adjustment for several clinical covariates.

Results

Among the 1,382 HF patients with KB measurements, the median (IQR) age was 78 (68, 84) and 52% were men. The median (IQR) KB was found to be 180 (134, 308) μM. Higher KB levels were associated with advanced HF (NYHA class III-IV) and higher NT-proBNP levels (both P < 0.001). The median follow-up was 13.9 years, and the 5-year mortality rate was 51.8% [95% confidence interval (CI): 49.1%-54.4%]. The risk of death increased when KB levels were higher (HRhigh vs. low group 1.23; 95% CI: 1.05-1.44), independently of a validated clinical risk score. The association between higher KB and mortality differed by ejection fraction (EF) and was noticeably stronger among patients with preserved EF.

Conclusions

Most patients with HF exhibited KB levels that were consistent with those found in healthy adults. Elevated levels of KB were observed in patients with advanced HF. Higher KB levels were found to be associated with an increased risk of death, particularly in patients with preserved EF.

Defining ketone supplementation: the evolving evidence for postexercise ketone supplementation to improve recovery and adaptation to exercise

Over the last decade, there has been a growing interest in the use of ketone supplements to improve athletic performance. These ketone supplements transiently elevate the concentrations of the ketone bodies acetoacetate (AcAc) and d-β-hydroxybutyrate (βHB) in the circulation. Early studies showed that ketone bodies can improve energetic efficiency in striated muscle compared with glucose oxidation and induce a glycogen-sparing effect during exercise. As such, most research has focused on the potential of ketone supplementation to improve athletic performance via ingestion of ketones immediately before or during exercise. However, subsequent studies generally observed no performance improvement, and particularly not under conditions that are relevant for most athletes. However, more and more studies are reporting beneficial effects when ketones are ingested after exercise. As such, the real potential of ketone supplementation may rather be in their ability to enhance postexercise recovery and training adaptations. For instance, recent studies observed that postexercise ketone supplementation (PEKS) blunts the development of overtraining symptoms, and improves sleep, muscle anabolic signaling, circulating erythropoietin levels, and skeletal muscle angiogenesis. In this review, we provide an overview of the current state-of-the-art about the impact of PEKS on aspects of exercise recovery and training adaptation, which is not only relevant for athletes but also in multiple clinical conditions. In addition, we highlight the underlying mechanisms by which PEKS may improve exercise recovery and training adaptation. This includes epigenetic effects, signaling via receptors, modulation of neurotransmitters, energy metabolism, and oxidative and anti-inflammatory pathways.

Molecular Mechanisms of Neuroprotection by Ketone Bodies and Ketogenic Diet in Cerebral Ischemia and Neurodegenerative Diseases

Ketone bodies (KBs), such as acetoacetate and β-hydroxybutyrate, serve as crucial alternative energy sources during glucose deficiency. KBs, generated through ketogenesis in the liver, are metabolized into acetyl-CoA in extrahepatic tissues, entering the tricarboxylic acid cycle and electron transport chain for ATP production. Reduced glucose metabolism and mitochondrial dysfunction correlate with increased neuronal death and brain damage during cerebral ischemia and neurodegeneration. Both KBs and the ketogenic diet (KD) demonstrate neuroprotective effects by orchestrating various cellular processes through metabolic and signaling functions. They enhance mitochondrial function, mitigate oxidative stress and apoptosis, and regulate epigenetic and post-translational modifications of histones and non-histone proteins. Additionally, KBs and KD contribute to reducing neuroinflammation and modulating autophagy, neurotransmission systems, and gut microbiome. This review aims to explore the current understanding of the molecular mechanisms underpinning the neuroprotective effects of KBs and KD against brain damage in cerebral ischemia and neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease.

Metabolomics, Lipidomics, and Antipsychotics: A Systematic Review

Antipsychotics are an important pharmacotherapy option for the treatment of many mental illnesses. Unfortunately, selecting antipsychotics is often a trial-and-error process due to a lack of understanding as to which medications an individual patient will find most effective and best tolerated. Metabolomics, or the study of small molecules in a biosample, is an increasingly used omics platform that has the potential to identify biomarkers for medication efficacy and toxicity. This systematic review was conducted to identify metabolites and metabolomic pathways associated with antipsychotic use in humans. Ultimately, 42 studies were identified for inclusion in this review, with all but three studies being performed in blood sources such as plasma or serum. A total of 14 metabolite classes and 12 lipid classes were assessed across studies. Although the studies were highly heterogeneous in approach and mixed in their findings, increases in phosphatidylcholines, decreases in carboxylic acids, and decreases in acylcarnitines were most consistently noted as perturbed in patients exposed to antipsychotics. Furthermore, for the targeted metabolomic and lipidomic studies, seven metabolites and three lipid species had findings that were replicated. The most consistent finding for targeted studies was an identification of a decrease in aspartate with antipsychotic treatment. Studies varied in depth of detail provided for their study participants and in study design. For example, in some cases, there was a lack of detail on specific antipsychotics used or concomitant medications, and the depth of detail on sample handling and analysis varied widely. The conclusions here demonstrate that there is a large foundation of metabolomic work with antipsychotics that requires more complete reporting so that an objective synthesis such as a meta-analysis can take place. This will then allow for validation and clinical application of the most robust findings to move the field forward. Future studies should be carefully controlled to take advantage of the sensitivity of metabolomics while limiting potential confounders that may result from participant heterogeneity and varied analysis approaches.

Metabolic Messengers: ketone bodies

Prospective molecular targets and therapeutic applications for ketone body metabolism have increased exponentially in the past decade. Initially considered to be restricted in scope as liver-derived alternative fuel sources during periods of carbohydrate restriction or as toxic mediators during diabetic ketotic states, ketogenesis and ketone bodies modulate cellular homeostasis in multiple physiological states through a diversity of mechanisms. Selective signalling functions also complement the metabolic fates of the ketone bodies acetoacetate and D-β-hydroxybutyrate. Here we discuss recent discoveries revealing the pleiotropic roles of ketone bodies, their endogenous sourcing, signalling mechanisms and impact on target organs, and considerations for when they are either stimulated for endogenous production by diets or pharmacological agents or administered as exogenous wellness-promoting agents.

The Impact of Ketone Body Metabolism on Mitochondrial Function and Cardiovascular Diseases

Ketone bodies, consisting of beta-hydroxybutyrate, acetoacetate, and acetone, are metabolic byproducts known as energy substrates during fasting. Recent advancements have shed light on the multifaceted effects of ketone body metabolism, which led to increased interest in therapeutic interventions aimed at elevating ketone body levels. However, excessive elevation of ketone body concentration can lead to ketoacidosis, which may have fatal consequences. Therefore, in this review, we aimed to focus on the latest insights on ketone body metabolism, particularly emphasizing its association with mitochondria as the primary site of interaction. Given the distinct separation between ketone body synthesis and breakdown pathways, we provide an overview of each metabolic pathway. Additionally, we discuss the relevance of ketone bodies to conditions such as nonalcoholic fatty liver disease or nonalcoholic steatohepatitis and cardiovascular diseases. Moreover, we explore the utilization of ketone body metabolism, including dietary interventions, in the context of aging, where mitochondrial dysfunction plays a crucial role. Through this review, we aim to present a comprehensive understanding of ketone body metabolism and its intricate relationship with mitochondrial function, spanning the potential implications in various health conditions and the aging process.

Ketogenic Diet Regulates Cardiac Remodeling and Calcium Homeostasis in Diabetic Rat Cardiomyopathy

A ketogenic diet (KD) might alleviate patients with diabetic cardiomyopathy. However, the underlying mechanism remains unclear. Myocardial function and arrhythmogenesis are closely linked to calcium (Ca2+) homeostasis. We investigated the effects of a KD on Ca2+ homeostasis and electrophysiology in diabetic cardiomyopathy. Male Wistar rats were created to have diabetes mellitus (DM) using streptozotocin (65 mg/kg, intraperitoneally), and subsequently treated for 6 weeks with either a normal diet (ND) or a KD. Our electrophysiological and Western blot analyses assessed myocardial Ca2+ homeostasis in ventricular preparations in vivo. Unlike those on the KD, DM rats treated with an ND exhibited a prolonged QTc interval and action potential duration. Compared to the control and DM rats on the KD, DM rats treated with an ND also showed lower intracellular Ca2+ transients, sarcoplasmic reticular Ca2+ content, sodium (Na+)-Ca2+ exchanger currents (reverse mode), L-type Ca2+ contents, sarcoplasmic reticulum ATPase contents, Cav1.2 contents. Furthermore, these rats exhibited elevated ratios of phosphorylated to total proteins across multiple Ca2+ handling proteins, including ryanodine receptor 2 (RyR2) at serine 2808, phospholamban (PLB)-Ser16, and calmodulin-dependent protein kinase II (CaMKII). Additionally, DM rats treated with an ND demonstrated a higher frequency and incidence of Ca2+ leak, cytosolic reactive oxygen species, Na+/hydrogen-exchanger currents, and late Na+ currents than the control and DM rats on the KD. KD treatment may attenuate the effects of DM-dysregulated Na+ and Ca2+ homeostasis, contributing to its cardioprotection in DM.

Dapagliflozin Attenuates Heart Failure With Preserved Ejection Fraction Remodeling and Dysfunction by Elevating β-Hydroxybutyrate-activated Citrate Synthase

ABSTRACT

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent, accounting for 50% of all heart failure patients, and is associated with significant mortality. Sodium-glucose cotransporter subtype inhibitor (SGLT2i) is recommended in the AHA and ESC guidelines for the treatment of HFpEF, but the mechanism of SGLT2i to prevent and treat cardiac remodeling and dysfunction is currently unknown, hindering the understanding of the pathophysiology of HFpEF and the development of novel therapeutics. HFpEF model was induced by a high-fat diet (60% calories from lard) + N [w] -nitro- l -arginine methyl ester ( l -NAME-0.5 g/L) (2 Hit) in male Sprague Dawley rats to effectively recapture the myriad phenotype of HFpEF. This study's results showed that administration of dapagliflozin (DAPA, SGLT2 inhibitor) significantly limited the 2-Hit-induced cardiomyocyte hypertrophy, apoptosis, inflammation, oxidative stress, and fibrosis. It also improved cardiac diastolic and systolic dysfunction in a late-stage progression of HFpEF. Mechanistically, DAPA influences energy metabolism associated with fatty acid intake and mitochondrial dysfunction in HFpEF by increasing β-hydroxybutyric acid (β-OHB) levels, directing the activation of citrate synthase, reducing acetyl coenzyme A (acetyl-CoA) pools, modulating adenosine 5'-triphosphate production, and increasing the expression of mitochondrial oxidative phosphorylation system complexes I-V. In addition, following clinical DAPA therapy, the blood levels of β-OHB and citrate synthase increased and the levels of acetyl-CoA in the blood of HFpEF patients decreased. SGLT2i plays a beneficial role in the prevention and treatment of cardiac remodeling and dysfunction in HFpEF model by attenuating cardiometabolic dysregulation.

Current Advances of Mitochondrial Dysfunction and Cardiovascular Disease and Promising Therapeutic Strategies

Mitochondria are cellular power stations and essential organelles for maintaining cellular homeostasis. Dysfunctional mitochondria have emerged as a key factor in the occurrence and development of cardiovascular disease. This review focuses on advances in the relationship between mitochondrial dysfunction and cardiovascular diseases such as atherosclerosis, heart failure, myocardial ischemia reperfusion injury, and pulmonary arterial hypertension. The clinical value and challenges of mitochondria-targeted strategies, including mitochondria-targeted antioxidants, mitochondrial quality control modulators, mitochondrial function protectors, mitochondrial biogenesis promoters, and recently developed mitochondrial transplants, are also discussed.

Prospective association between an obesogenic dietary pattern in early adolescence and metabolomics derived and traditional cardiometabolic risk scores in adolescents and young adults from the ALSPAC cohort

BACKGROUND

Dietary intake during early life may be a modifying factor for cardiometabolic risk (CMR). Metabolomic profiling may enable more precise identification of CMR in adolescence than traditional CMR scores. We aim to assess and compare the prospective associations between an obesogenic dietary pattern (DP) score at age 13 years with a novel vs. traditional CMR score in adolescence and young adulthood in the Avon Longitudinal Study of Parents and Children (ALSPAC).

METHODS

Study participants were ALSPAC children with diet diary data at age 13. The obesogenic DP z-score, characterized by high energy-density, high % of energy from total fat and free sugars, and low fibre density, was previously derived using reduced rank regression. CMR scores were calculated by combining novel metabolites or traditional risk factors (fat mass index, insulin resistance, mean arterial blood pressure, triacylglycerol, HDL and LDL cholesterol) at age 15 (n = 1808), 17 (n = 1629), and 24 years (n = 1760). Multivariable linear regression models estimated associations of DP z-score with log-transformed CMR z-scores.

RESULTS

Compared to the lowest tertile, the highest DP z-score tertile at age 13 was associated with an increase in the metabolomics CMR z-score at age 15 (β = 0.20, 95% CI 0.09, 0.32, p trend < 0.001) and at age 17 (β = 0.22, 95% CI 0.10, 0.34, p trend < 0.001), and with the traditional CMR z-score at age 15 (β = 0.15, 95% CI 0.05, 0.24, p trend 0.020). There was no evidence of an association at age 17 for the traditional CMR z-score (β = 0.07, 95% CI -0.03, 0.16, p trend 0.137) or for both scores at age 24.

CONCLUSIONS

An obesogenic DP was associated with greater CMR in adolescents. Stronger associations were observed with a novel metabolite CMR score compared to traditional risk factors. There may be benefits from modifying diet during adolescence for CMR health, which should be prioritized for further research in trials.

The Association between Circulating 25-Hydroxyvitamin D and Carotid Intima-Media Thickness Is Mediated by Gut Microbiota and Fecal and Serum Metabolites in Adults

SCOPE

Vitamin D is vital to cardiovascular health. This study examines the association between plasma 25-hydroxyvitamin D (25[OH]D) and the progression of carotid intima-media thickness (cIMT) and identifies the potential mediating biomarkers of gut microbiota and metabolites in adults.

METHODS AND RESULTS

This 9-year prospective study includes 2975 subjects with plasma 25(OH)D at baseline and determined cIMT every 3 years. Higher circulating 25(OH)D is associated with decreased odds of higher (≥median) 9-year cIMT changes at the common carotid artery (hΔCCA-cIMT) (p-trend < 0.001). Multivariable-adjusted OR (95%CI) of hΔCCA-cIMT for tertiles 2 and 3 (vs. 1) of 25(OH)D is 0.87 (0.73-1.04) and 0.68 (0.57-0.82). Gut microbiome and metabolome analysis identify 18 biomarkers significantly associated with both 25(OH)D and hΔCCA-cIMT, including three microbial genera, seven fecal metabolites, eight serum metabolites, and pathway of synthesis and degradation of ketone bodies. Mediation/path analyses show the scores generated from the overlapped differential gut microbiota, fecal and serum metabolites, and serum acetoacetic acid alone could mediate the beneficial association between 25(OH)D and hΔCCA-cIMT by 10.8%, 23.1%, 59.2%, and 62.0% (all p < 0.05), respectively.

CONCLUSIONS

These findings show a beneficial association between plasma 25(OH)D and the CCA-cIMT progression. The identified multi-omics biomarkers provide novel mechanistic insights for the epidemiological association.

Fasting Ketone Bodies and Incident Type 2 Diabetes in the General Population

With rising incidence and prevalence of type 2 diabetes, prevention including identification of prospective biomarkers becomes increasingly relevant. Although ketone bodies recently received a renewed interest as potential biomarkers, data linking these metabolites to diabetes risk are scarce. Therefore, the present prospective study investigated a potential association between fasting ketone bodies and incident type 2 diabetes in the general population. This study from the PREVEND cohort included 3,307 participants from the general population initially free of diabetes or impaired fasting glucose. Baseline fasting ketone body concentrations were measured by nuclear magnetic resonance spectroscopy. One hundred twenty-six participants (3.8%) developed type 2 diabetes during a median (interquartile range) follow-up of 7.3 (6.3-7.6) years. In Kaplan-Meier analysis, sex-stratified ketone body levels strongly positively associated with incident type 2 diabetes, which was confirmed in Cox regression analyses adjusted for several potential confounders. There was no significant interaction by sex. Both 3-β-hydroxybutyrate and acetoacetate+acetone individually associated with incident type 2 diabetes. In conclusion, fasting plasma ketone body levels are strongly positively associated with incident type 2 diabetes in the general population independent of several other recognized risk factors. These results may have important implications for diabetes prevention including dietary strategies.

ARTICLE HIGHLIGHTS

The identification of biomarkers that predict type 2 diabetes is increasingly relevant for personalized medicine strategies. Data regarding ketone bodies and incident type 2 diabetes are scarce. This study shows that ketone bodies, either combined or as individual subspecies, are strongly associated with incident type 2 diabetes in the general population, independent of potential confounders. These results may have important implications for diabetes prevention including dietary strategies.

MCT-Induced Ketosis and Fiber in Rheumatoid Arthritis (MIKARA)-Study Protocol and Primary Endpoint Results of the Double-Blind Randomized Controlled Intervention Study Indicating Effects on Disease Activity in RA Patients

Fatty acids, such as medium-chain fatty acids (MCFAs) and short-chain fatty acids (SCFAs), both important components of a normal diet, have been reported to play a role in bone-related diseases such as rheumatoid arthritis (RA). However, the role of medium-chain triglycerides (MCTs) has not been investigated in RA to date. The aim of this study was to investigate the effect of supplementation of regular diet with MCT with and without fiber on disease activity as measured with the SDAI (Simplified Disease Activity Index) in RA patients. A total of 61 RA patients on stable drug treatment were randomly assigned to a twice-daily control regimen or to a twice-daily regimen of a formulation containing medium-chain triglycerides (MCTs) 30 g/day for 8 weeks followed by a second twice-daily regimen of combining MCT (30 g/day) plus fiber (30 g/day) for an additional 8 weeks. The control group received a formulation containing long-chain triglycerides (LCTs) instead of MCTs. The preliminary results showed a significant reduction in SDAI from baseline to week 16 in the test group and a significant increase in β-hydroxybutyrate (BHB) levels, while no improvement in SDAI was observed in the control group.

Integrative analysis of mitochondrial metabolic reprogramming in early-stage colon and liver cancer

Gastrointestinal malignancies, including colon adenocarcinoma (COAD) and liver hepatocellular carcinoma (LIHC), remain leading causes of cancer-related deaths worldwide. To better understand the underlying mechanisms of these cancers and identify potential therapeutic targets, we analyzed publicly accessible Cancer Genome Atlas datasets of COAD and LIHC. Our analysis revealed that differentially expressed genes (DEGs) during early tumorigenesis were associated with cell cycle regulation. Additionally, genes related to lipid metabolism were significantly enriched in both COAD and LIHC, suggesting a crucial role for dysregulated lipid metabolism in their development and progression. We also identified a subset of DEGs associated with mitochondrial function and structure, including upregulated genes involved in mitochondrial protein import and respiratory complex assembly. Further, we identified mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) as a crucial regulator of cancer cell metabolism. Using a genome-scale metabolic model, we demonstrated that HMGCS2 suppression increased glycolysis, lipid biosynthesis, and elongation while decreasing fatty acid oxidation in colon cancer cells. Our study highlights the potential contribution of dysregulated lipid metabolism, including ketogenesis, to COAD and LIHC development and progression and identifies potential therapeutic targets for these malignancies.

Impact of Geroscience on Therapeutic Strategies for Older Adults With Cardiovascular Disease: JACC Scientific Statement

Geroscience posits that cardiovascular disease (CVD) and other chronic diseases result from progressive erosion of the effectiveness of homeostatic mechanisms that oppose age-related accumulation of molecular damage. This hypothetical common root to chronic diseases explains why patients with CVD are often affected by multimorbidity and frailty and why older age negatively affects CVD prognosis and treatment response. Gerotherapeutics enhance resilience mechanisms that counter age-related molecular damage to prevent chronic diseases, frailty, and disability, thereby extending healthspan. Here, we describe the main resilience mechanisms of mammalian aging, with a focus on how they can affect CVD pathophysiology. We next present novel gerotherapeutic approaches, some of which are already used in management of CVD, and explore their potential to transform care and management of CVD. The geroscience paradigm is gaining traction broadly in medical specialties, with potential to mitigate premature aging, reduce health care disparities, and improve population healthspan.

Comparative Metabolomics in Single Ventricle Patients after Fontan Palliation: A Strong Case for a Targeted Metabolic Therapy

Most studies on single ventricle (SV) circulation take a physiological or anatomical approach. Although there is a tight coupling between cardiac contractility and metabolism, the metabolic perspective on this patient population is very recent. Early findings point to major metabolic disturbances, with both impaired glucose and fatty acid oxidation in the cardiomyocytes. Additionally, Fontan patients have systemic metabolic derangements such as abnormal glucose metabolism and hypocholesterolemia. Our literature review compares the metabolism of patients with a SV circulation after Fontan palliation with that of patients with a healthy biventricular (BV) heart, or different subtypes of a failing BV heart, by Pubmed review of the literature on cardiac metabolism, Fontan failure, heart failure (HF), ketosis, metabolism published in English from 1939 to 2023. Early evidence demonstrates that SV circulation is not only a hemodynamic burden requiring staged palliation, but also a metabolic issue with alterations similar to what is known for HF in a BV circulation. Alterations of fatty acid and glucose oxidation were found, resulting in metabolic instability and impaired energy production. As reported for patients with BV HF, stimulating ketone oxidation may be an effective treatment strategy for HF in these patients. Few but promising clinical trials have been conducted thus far to evaluate therapeutic ketosis with HF using a variety of instruments, including ketogenic diet, ketone esters, and sodium-glucose co-transporter-2 (SGLT2) inhibitors. An initial trial on a small cohort demonstrated favorable outcomes for Fontan patients treated with SGLT2 inhibitors. Therapeutic ketosis is worth considering in the treatment of Fontan patients, as ketones positively affect not only the myocardial energy metabolism, but also the global Fontan physiopathology. Induced ketosis seems promising as a concerted therapeutic strategy.

The Ketogenic Diet and Cardiovascular Diseases

The most common and increasing causes of death worldwide are cardiovascular diseases (CVD). Taking into account the fact that diet is a key factor, it is worth exploring this aspect of CVD prevention and therapy. The aim of this article is to assess the potential of the ketogenic diet in the prevention and treatment of CVD. The article is a comprehensive, meticulous analysis of the literature in this area, taking into account the most recent studies currently available. The ketogenic diet has been shown to have a multifaceted effect on the prevention and treatment of CVD. Among other aspects, it has a beneficial effect on the blood lipid profile, even compared to other diets. It shows strong anti-inflammatory and cardioprotective potential, which is due, among other factors, to the anti-inflammatory properties of the state of ketosis, the elimination of simple sugars, the restriction of total carbohydrates and the supply of omega-3 fatty acids. In addition, ketone bodies provide "rescue fuel" for the diseased heart by affecting its metabolism. They also have a beneficial effect on the function of the vascular endothelium, including improving its function and inhibiting premature ageing. The ketogenic diet has a beneficial effect on blood pressure and other CVD risk factors through, among other aspects, weight loss. The evidence cited is often superior to that for standard diets, making it likely that the ketogenic diet shows advantages over other dietary models in the prevention and treatment of cardiovascular diseases. There is a legitimate need for further research in this area.

Metabolic Approaches for the Treatment of Dilated Cardiomyopathy

In dilated cardiomyopathy (DCM), where the heart muscle becomes stretched and thin, heart failure (HF) occurs, and the cardiomyocytes suffer from an energetic inefficiency caused by an abnormal cardiac metabolism. Although underappreciated as a potential therapeutic target, the optimal metabolic milieu of a failing heart is still largely unknown and subject to debate. Because glucose naturally has a lower P/O ratio (the ATP yield per oxygen atom), the previous studies using this strategy to increase glucose oxidation have produced some intriguing findings. In reality, the vast majority of small-scale pilot trials using trimetazidine, ranolazine, perhexiline, and etomoxir have demonstrated enhanced left ventricular (LV) function and, in some circumstances, myocardial energetics in chronic ischemic and non-ischemic HF with a reduced ejection fraction (EF). However, for unidentified reasons, none of these drugs has ever been tested in a clinical trial of sufficient size. Other pilot studies came to the conclusion that because the heart in severe dilated cardiomyopathy appears to be metabolically flexible and not limited by oxygen, the current rationale for increasing glucose oxidation as a therapeutic target is contradicted and increasing fatty acid oxidation is supported. As a result, treating metabolic dysfunction in HF may benefit from raising ketone body levels. Interestingly, treatment with sodium-glucose cotransporter-2 inhibitors (SGLT2i) improves cardiac function and outcomes in HF patients with or without type 2 diabetes mellitus (T2DM) through a variety of pleiotropic effects, such as elevated ketone body levels. The improvement in overall cardiac function seen in patients receiving SGLT2i could be explained by this increase, which appears to be a reflection of an adaptive process that optimizes cardiac energy metabolism. This review aims to identify the best metabolic therapeutic approach for DCM patients, to examine the drugs that directly affect cardiac metabolism, and to outline all the potential ancillary metabolic effects of the guideline-directed medical therapy. In addition, a special focus is placed on SGLT2i, which were first studied and prescribed to diabetic patients before being successfully incorporated into the pharmacological arsenal for HF patients.

An open-label, acute clinical trial in adults to assess ketone levels, gastrointestinal tolerability, and sleepiness following consumption of (R)-1,3-butanediol (Avela™)

Introduction: A study was undertaken to determine the acute effects of a beverage made with Avela™ (R)-1,3-butanediol, on blood beta-hydroxybutyrate (BHB) levels (using the Keto-Mojo monitor), gastrointestinal (GI) tolerability (using the modified visual analogue scale GI Symptoms Tool), and sleepiness (using the Stanford Sleepiness Scale). Methods: Following a 12-h overnight fast, 26 healthy adults consumed one beverage containing 11.5 g of (R)-1,3-butanediol at each of 0, 30, and 60 min, culminating in a total intake of 34.5 g of (R)-1,3-butanediol. Blood BHB levels, GI tolerability, and sleepiness were assessed at baseline (0 min), and at 30, 60, 90, 120, 180, 240, and 300 min. At 240 min, a protein bar was consumed. Results: The mean (±SD) BHB fasting baseline level, maximal concentration, time at maximal concentration, and incremental area under the curve over 300 min were 0.23 ± 0.21 mmol/L, 2.10 ± 0.97 mmol/L, 133.85 ± 57.07 min, and 376.73 ± 156.76 mmol/L*min, respectively. BHB levels at each time point were significantly increased relative to baseline. In females, BHB T_max was significantly greater (p = 0.046), and BHB iAUC_0-300 min nearly significantly greater (p = 0.06) than in males. Discussion: The beverage formulated with Avela™ had no impact on sleepiness and was generally well-tolerated, with no or mild GI symptoms reported in most participants. Mild headaches were reported as an adverse event by five participants and judged possibly related to the study product in two of the participants.

Novelties in the pharmacological approaches for chronic heart failure: new drugs and cardiovascular targets

Despite recent advances in chronic heart failure (HF) management, the prognosis of HF patients is poor. This highlights the need for researching new drugs targeting, beyond neurohumoral and hemodynamic modulation approach, such as cardiomyocyte metabolism, myocardial interstitium, intracellular regulation and NO-sGC pathway. In this review we report main novelties on new possible pharmacological targets for HF therapy, mainly on new drugs acting on cardiac metabolism, GCs-cGMP pathway, mitochondrial function and intracellular calcium dysregulation.

Recent Advances in Translational Research for Heart Failure in Japan

Despite decades of intensive research and therapeutic development, heart failure remains a leading cause of death worldwide. However, recent advances in several basic and translational research fields, such as genomic analysis and single-cell analysis, have increased the possibility of developing novel diagnostic approaches to heart failure. Most cardiovascular diseases that predispose individuals to heart failure are caused by genetic and environmental factors. It follows that genomic analysis can contribute to the diagnosis and prognostic stratification of patients with heart failure. In addition, single-cell analysis has shown great potential for unveiling the pathogenesis and/or pathophysiology and for discovering novel therapeutic targets for heart failure. Here, we summarize the recent advances in translational research on heart failure in Japan, based mainly on our studies.

Mapping the Unseen: In Vivo CEST-MRI of Creatine Reveals Improved Cardiac Energetics in Subjects with Obesity Following Bariatric Surgery

BACKGROUND

Obesity is associated with derangement of cardiac metabolism and the development of subclinical cardiovascular disease. This prospective study examined the impact of bariatric surgery on cardiac function and metabolism.

METHODS

Subjects with obesity underwent cardiac magnetic resonance imaging (CMR) at Massachusetts General Hospital before and after bariatric surgery between 2019 and 2021. The imaging protocol included Cine for global cardiac function assessment and creatine chemical exchange saturation transfer (CEST) CMR for myocardial creatine mapping.

RESULTS

Thirteen subjects were enrolled, and 6 subjects [mean BMI 40.5 ± 2.6] had completed the second CMR (i.e. post-surgery), with a median follow-up of 10 months. The median age was 46.5 years, 67% were female, and 16.67% had diabetes. Bariatric surgery led to significant weight loss, with achieved mean BMI of 31.0 ± 2.0. Additionally, bariatric surgery resulted in significant reduction in left ventricular (LV) mass, LV mass index, and epicardial adipose tissue (EAT) volume. This was accompanied by slight improvement in LV ejection fraction compared to baseline. Following bariatric surgery, there was a significant increase in creatine CEST contrast. Subjects with obesity had significantly lower CEST contrast compared to subjects with normal BMI (n = 10), but this contrast was normalized after the surgery, and statistically similar to non-obese cohort, indicating an improvement in myocardial energetics.

CONCLUSIONS

CEST-CMR has the ability to identify and characterize myocardial metabolism in vivo non-invasively. These results demonstrate that in addition to reducing BMI, bariatric surgery may favorably affect cardiac function and metabolism.

Ketone ester supplementation suppresses cardiac inflammation and improves cardiac energetics in a swine model of acute myocardial infarction

BACKGROUND

Myocardial infarction (MI) is a major risk factor for the development of heart failure with reduce ejection fraction (HFrEF). While previous studies have focused on HFrEF, the cardiovascular effects of ketone bodies in acute MI are unclear. We examined the effects of oral ketone supplementation as a potential treatment strategy in a swine acute MI model.

METHODS

Farm pigs underwent percutaneous balloon occlusion of the LAD for 80 min followed by 72 h reperfusion period. Oral ketone ester or vehicle was administered during reperfusion and continued during the follow-up period.

RESULTS

Oral KE supplementation induced ketonemia 2-3 mmol/l within 30 min after ingestion. KE increased ketone (βHB) extraction in healthy hearts without affecting glucose and fatty acid (FA) consumption. During reperfusion, the MI hearts consumed less FA with no change in glucose consumption, whereas hearts from MI-KE-fed animals consumed more βHB and FA, as well as improved myocardial ATP production. A significant elevation of infarct T2 values indicative of inflammation was found only in untreated MI group compared to sham. Concordantly, cardiac expression of inflammatory markers, oxidative stress, and apoptosis were reduced by KE. RNA-seq analysis identified differentially expressed genes related to mitochondrial energy metabolism and inflammation.

CONCLUSIONS

Oral KE supplementation induced ketosis and enhanced myocardial βHB extraction in both healthy and infarcted hearts. Acute oral supplementation with KE favorably altered cardiac substrate uptake and utilization, improved cardiac ATP levels, and reduced cardiac inflammation following MI.

Hemodynamic Effects of Ketone Bodies in Patients With Pulmonary Hypertension

Background Pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) are debilitating diseases with a high mortality. Despite emerging treatments, pulmonary vascular resistance frequently remains elevated. However, the ketone body 3-hydroxybutyrate (3-OHB) may reduce pulmonary vascular resistance in these patients. Hence, the aim was to assess the hemodynamic effects of 3-OHB in patients with PAH or CTEPH. Methods and Results We enrolled patients with PAH (n=10) or CTEPH (n=10) and residual pulmonary hypertension. They received 3-OHB infusion and placebo (saline) for 2 hours in a randomized crossover study. Invasive hemodynamic and echocardiography measurements were performed. Furthermore, we investigated the effects of 3-OHB on the right ventricle of isolated hearts and isolated pulmonary arteries from Sprague-Dawley rats. Ketone body infusion increased circulating 3-OHB levels from 0.5±0.5 to 3.4±0.7 mmol/L (P<0.001). Cardiac output improved by 1.2±0.1 L/min (27±3%, P<0.001), and right ventricular annular systolic velocity increased by 1.4±0.4 cm/s (13±4%, P=0.002). Pulmonary vascular resistance decreased by 1.3±0.3 Wood units (18%±4%, P<0.001) with no significant difference in response between patients with PAH and CTEPH. In the rat studies, 3-OHB administration was associated with decreased pulmonary arterial tension compared with saline administration (maximal relative tension difference: 12±2%, P<0.001) and had no effect on right ventricular systolic pressures (P=0.63), whereas pressures rose at a slower pace (dP/dtmax, P=0.02). Conclusions In patients with PAH or CTEPH, ketone body infusion improves cardiac output and decreases pulmonary vascular resistance. Experimental rat studies support that ketone bodies relax pulmonary arteries. Long-term studies are warranted to assess the clinical role of hyperketonemia. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04615754.

Nutritional management of glycogen storage disease type III: a case report and a critical appraisal of the literature

Glycogen storage disease Type III (GSD III) is an autosomal recessive disease due to the deficiency of the debranching enzyme, which has two main consequences: a reduced availability of glucose due to the incomplete degradation of glycogen, and the accumulation of abnormal glycogen in liver and cardiac/skeletal muscle. The role of dietary lipid manipulations in the nutritional management of GSD III is still debated. A literature overview shows that low-carbohydrate (CHO) / high-fat diets may be beneficial in reducing muscle damage. We present a 24-year GSD IIIa patient with severe myopathy and cardiomyopathy in whom a gradual shift from a high-CHO diet (61% total energy intake), low-fat (18%), high-protein (21%) to a low-CHO (32 %) high-fat (45%) / high-protein (23%) diet was performed. CHO was mainly represented by high-fiber, low glycemic index food, and fat consisted prevalently of mono and polyunsaturated fatty acids. After a 2-year follow-up, all biomarkers of muscle and heart damage markedly decreased (by 50-75%), glucose levels remained within the normal range and lipid profile was unchanged. At echocardiography, there was an improvement in geometry and left ventricular function. A low -CHO, high-fat, high-protein diet seems to be safe, sustainable and effective in reducing muscle damage without worsening cardiometabolic profile in GSDIIIa. This dietary approach could be started as early as possible in GSD III displaying skeletal/cardiac muscle disease in order to prevent/minimize organ damage.

The Alterations of Gut Microbiome and Lipid Metabolism in Patients with Spinal Muscular Atrophy

INTRODUCTION

Spinal muscular atrophy (SMA) can cause multiple system dysfunction, especially lipid metabolic disorders, for which management strategies are currently lacking. Microbes are related to metabolism and the pathogenesis of neurological diseases. This study aimed to preliminarily explore the alterations in the gut microbiota in SMA and the potential relationship between altered microbiota and lipid metabolic disorders.

METHODS

Fifteen patients with SMA and 17 gender- and age-matched healthy controls were enrolled in the study. Feces and fasting plasma samples were collected. 16S ribosomal RNA sequencing and nontargeted metabolomics analysis were performed to explore the correlation between microbiota and differential lipid metabolites.

RESULTS

No significant difference was found in microbial diversity (α- and β-diversity) between the SMA and control groups, with both groups having a relatively similar community structure. However, compared to the control group, the SMA group showed an increased relative abundance of the genera Ruminiclostridium, Gordonibacter, Enorma, Lawsonella, Frisingicoccus, and Anaerofilum and a decreased abundance of the genera Catabacter, Howardella, Marine_Methylotrophic_Group_3, and Lachnospiraceae_AC2044_group. The concurrent metabolomic analysis showed that the SMA group had 56 different kinds of lipid metabolite levels than did the control group. Additionally, the Spearman correlation suggested a correlation between the altered differential lipid metabolites and the above-mentioned altered microbiota.

CONCLUSIONS

The gut microbiome and lipid metabolites differed between the patients with SMA and the control subjects. The altered microbiota may be related with the lipid metabolic disorders in SMA. However, further study is necessary to clarify the mechanism of lipid metabolic disorders and develop management strategies to improve the related complications in SMA.

Cardioprotective Effect of Empagliflozin and Circulating Ketone Bodies During Acute Myocardial Infarction

BACKGROUND

SGLT2i (sodium-glucose cotransporter-2 inhibitors) improve clinical outcomes in patients with heart failure, but the mechanisms of action are not completely understood. SGLT2i increases circulating levels of ketone bodies, which has been demonstrated to enhance myocardial energetics and induce reverse ventricular remodeling. However, the role of SGLT2i or ketone bodies on myocardial ischemia reperfusion injury remains in the dark. The objective of this study is to investigate the cardioprotective potential of empagliflozin and ketone bodies during acute myocardial infarction (MI).

METHODS

We used a nondiabetic porcine model of ischemia reperfusion using a percutaneous occlusion of proximal left anterior descending artery for 45 minutes. Animals received 1-week pretreatment with either empagliflozin or placebo prior to MI induction. Additionally, a third group received intravenous infusion of the ketone body BOHB (beta-hydroxybutyrate) during the MI induction. Acute effects of the treatments were assessed 4-hour post-MI by cardiac magnetic resonance and histology (thioflavin for area at risk, triphenyltetrazolium chloride staining for MI size). All animals were euthanized immediately postcardiac magnetic resonance, and heart samples were collected.

RESULTS

The area at risk was similar in all groups. Empagliflozin treatment increased BOHB levels. Empagliflozin-treated animals showed significantly higher myocardial salvage, smaller MI size (both by cardiac magnetic resonance and histology), less microvascular obstruction, and improved cardiac function (left ventricle ejection fraction and strain). Furthermore, empagliflozin-treated animals demonstrated reduced biomarkers of cardiomyocyte apoptosis and oxidative stress compared with placebo. The BOHB group showed similar results to the empagliflozin group.

CONCLUSIONS

One-week pretreatment with empagliflozin ameliorates ischemia reperfusion injury, reduces MI size and microvascular obstruction, increases myocardial salvage, preserves left ventricle systolic function, and lowers apoptosis and oxidative stress. Periprocedural intravenous infusion of BOHB during myocardial ischemia also induces cardioprotection, suggesting a role for BOHB availability as an additional mechanism within the wide spectrum of actions of SGLT2i.

The UPHILL study: A nutrition and lifestyle intervention to improve quality of life for patients with pulmonary arterial hypertension

The aim of the UPHILL study (a nutrition and lifestyle intervention in patients with pulmonary arterial hypertension [PAH]: effect on quality of life [QoL]), was to determine the effect of innovative nutritional interventions on adjustments in nutritional intake and QoL. In this study a group of prevalent PAH patients at a single center in Amsterdam (the Netherlands) was informed about healthy nutrition using a newly designed video e-learning. They were subsequently instructed to follow a healthy diet during dietary intervention. Nutritional intake was assessed using a food frequency questionnaire (HELIUS) and QoL by the short-form (SF)-36 questionnaire. Nutritional parameters were determined in blood samples. Seventeen patients stable under treatment, who had been diagnosed with PAH 7.0 [3.0-14.0] years before, started and completed the intervention (2 males, 15 females; 45.35 ± 13.57 years). Since all patients in the intervention group made behavioral changes in nutritional intake, during study and follow-up, nutritional and lifestyle adaptations persisted. Despite the fact that patients had already high mean scores at baseline for both mental (74.10 [60.51-84.25]) and physical QoL (66.46 [50.21-73.84]), scores improved further during e-learning. Furthermore, patients who realized most nutritional adaptations, had the best improvement in QoL. This pilot study showed that e-learning modules on nutrition provide an unique opportunity to change nutritional intake in PAH patients and by that improve QoL.

Beta-Hydroxybutyrate (BHB), Glucose, Insulin, Octanoate (C8), and Decanoate (C10) Responses to a Medium-Chain Triglyceride (MCT) Oil with and without Glucose: A Single-Center Study in Healthy Adults

MCTs are increasingly being used to promote ketogenesis by patients on ketogenic diet therapy, but also by people with other conditions and by the general public for the perceived potential benefits. However, consumption of carbohydrates with MCTs and untoward gastrointestinal side effects, especially at higher doses, could decrease the sustainability of the ketogenic response. This single-center study investigated the impact of consuming carbohydrate as glucose with MCT oil compared to MCT alone on the BHB response. The effects of MCT oil versus MCT oil plus glucose on blood glucose, insulin response, levels of C8, C10, BHB, and cognitive function were determined, and side effects were monitored. A significant plasma BHB increase with a peak at 60 min was observed in 19 healthy participants (24.4 ± 3.9 years) after consuming MCT oil alone, and a more delayed but slightly higher peak was observed after consuming MCT oil plus glucose. A significant increase in blood glucose and insulin levels occurred only after MCT oil plus glucose intake. The overall mean plasma levels of C8 and C10 were higher with the intake of MCT oil alone. MCT oil plus glucose consumption showed improved scores for the arithmetic and vocabulary subtests.