Impaired ketogenesis is associated with metabolic-associated fatty liver disease in subjects with type 2 diabetes

Plasma Beta-Hydroxybutyrate and All-Cause Mortality in Patients with Liver Cirrhosis

Background: Liver cirrhosis is often accompanied by metabolic dysfunction. Circulating β-hydroxybutyrate (BHB), the most abundant ketone body, is an emerging metabolic biomarker of mitochondrial dysfunction. Methods: In this prospective observational study, we evaluated plasma BHB concentrations in patients with cirrhosis compared to the general population and investigated their association with all-cause mortality in cirrhosis. Plasma BHB, measured by nuclear magnetic resonance spectroscopy, was compared between 125 patients with cirrhosis on the waiting list for liver transplantation (TransplantLines cohort study; NCT03272841) with 125 propensity-score-matched participants from the population-dwelling PREVEND cohort. Associations of BHB with all-cause mortality were established by tertile-based log-rank tests and Cox regression analyses. A generalized additive model was fitted to assess a potential non-linear association between BHB and mortality. Results: Patients with cirrhosis had lower plasma BHB concentrations than matched PREVEND participants (111.5 µmol/L vs. 138.4 µmol/L, p = 0.02). During 133 (interquartile range 42-375) days of follow up, 27 patients died. All-cause mortality was lowest in the middle BHB tertile and highest in the upper BHB tertile (p < 0.001 by log-rank test). A non-linear, J-shaped association between BHB levels and mortality risk was found with a higher risk of death with the highest and lowest BHB levels. In Cox regression analyses, adjusted for age, sex, MELD score, diabetes, and HDL cholesterol, mortality was highest in the highest BHB tertile (T3 vs. T2 HR: 7.6, 95% CI: 2.3-25.6, p < 0.001). Mortality also tended to be higher in the lowest vs. the middle (T1 vs. T2 HR: 3.5, 95% CI: 0.9-11.7, p = 0.06). Sensitivity analyses, excluding diabetic patients and those with metabolic dysfunction-associated steatotic liver disease, confirmed the robustness of these findings. Conclusion: BHB levels exhibit a J-shaped association with the risk of death in patients with liver cirrhosis. The highest circulating BHB levels are independently associated with increased mortality risk, potentially reflecting underlying metabolic dysregulation. Future studies are necessary to validate the utility of BHB as a prognostic target in cirrhosis.

The genetically predicted causal associations between circulating 3-hydroxybutyrate levels and malignant neoplasms: A pan-cancer Mendelian randomization study

OBJECTIVE

The ketogenic diet or exogenous supplementation with 3-hydroxybutyrate (3HB) is progressively gaining recognition as a valuable therapeutic or health intervention strategy. However, the effects of 3HB on cancers have been inconsistent in previous studies. This study aimed to comprehensively investigate the causal effects of circulating 3HB levels on 120 cancer phenotypes, and explore the 3HB mediation effect between liver fat accumulation and cancers.

METHODS

Univariate Mendelian randomization (UVMR) was used in this study to investigate the causal impact of circulating 3HB levels on cancers. We conducted meta-analyses for 3HB-cancer associations sourced from different exposure data. In multivariate MR(MVMR), the body mass index, alcohol frequency and diabetes were included as covariates to investigate the independent effect of 3HB on cancer risk. Additionally, utilizing mediation MR analysis, we checked the potential mediating role of 3HB in the association between liver fat and cancer.

RESULTS

Integrating findings from UVMR and MVMR, we observed that elevated circulating 3HB levels were associated with reduced risk of developing diffuse large B-cell lymphoma(DLBCL) (OR[95%CI] = 0.28[0.14-0.57] p = 3.92e-04), biliary malignancies (OR[95%CI] = 0.30[0.15-0.60], p = 7.67e-04), hepatocellular carcinoma(HCC) (OR[95%CI] = 0.25[0.09-0.71], p = 9.33e-03), primary lymphoid and hematopoietic malignancies (OR[95%CI] = 0.76[0.58-0.99], p = 0.045). Further UVMR analysis revealed that an increase in the percent liver fat was associated with reduced 3HB levels (Beta[95%CI] = -0.073[-0.122∼-0.024], p = 0.0034) and enhanced susceptibility to HCC (OR[95%CI] = 13.9[9.76-19.79], p = 3.14e-48), biliary malignancies (OR[95%CI] = 4.04[3.22-5.07], p = 1.64e-33), nasopharyngeal cancer (OR[95%CI] = 3.26[1.10-9.67], p = 0.03), and primary lymphoid and hematopoietic malignancies (OR[95%CI] = 1.27[1.13-1.44], p = 1.04e-4). Furthermore, 3HB fully mediated the effect of liver fat on susceptibility to DLBCL (OR[95%CI] = 1.076[1.01-1.15], p = 0.034).

CONCLUSIONS

Circulating 3HB is associated with a reduced susceptibility to developing DLBCL, HCC, biliary malignancies, and primary lymphoid and hematopoietic malignancies. The impaired ketogenesis induced by metabolic-dysfunction associated fatty liver disease (MAFLD) contributes to risk of DLBCL.

Ketone body metabolism and cardiometabolic implications for cognitive health

Cardiometabolic complications of obesity present a growing public health concern and are associated with poor outcomes, mediated in part by an increased risk for cardiovascular disease, metabolic dysfunction-associated fatty liver disease, and systemic insulin resistance. Recent studies support that both insulin resistance and obesity are also associated with aberrant brain metabolism and cognitive impairment similar to what is observed in neurodegenerative diseases. Central to these pathological outcomes are adverse changes in tissue glucose and ketone body metabolism, suggesting that regulation of substrate utilization could be a mechanistic link between the cardiometabolic outcomes of obesity and the progression of cognitive decline. Here, we review ketone body metabolism in physiological and pathological conditions with an emphasis on the therapeutic potential of ketone bodies in treating cardiometabolic diseases and neurodegenerative diseases that lead to cognitive decline. We highlight recent findings in the associations among cardiometabolic disease, ketone body metabolism, and cognitive health while providing a theoretical framework by which ketone bodies may promote positive health outcomes and preserve cognitive function.

The Metabolic Syndrome, a Human Disease

This review focuses on the question of metabolic syndrome (MS) being a complex, but essentially monophyletic, galaxy of associated diseases/disorders, or just a syndrome of related but rather independent pathologies. The human nature of MS (its exceptionality in Nature and its close interdependence with human action and evolution) is presented and discussed. The text also describes the close interdependence of its components, with special emphasis on the description of their interrelations (including their syndromic development and recruitment), as well as their consequences upon energy handling and partition. The main theories on MS's origin and development are presented in relation to hepatic steatosis, type 2 diabetes, and obesity, but encompass most of the MS components described so far. The differential effects of sex and its biological consequences are considered under the light of human social needs and evolution, which are also directly related to MS epidemiology, severity, and relations with senescence. The triggering and maintenance factors of MS are discussed, with especial emphasis on inflammation, a complex process affecting different levels of organization and which is a critical element for MS development. Inflammation is also related to the operation of connective tissue (including the adipose organ) and the widely studied and acknowledged influence of diet. The role of diet composition, including the transcendence of the anaplerotic maintenance of the Krebs cycle from dietary amino acid supply (and its timing), is developed in the context of testosterone and β-estradiol control of the insulin-glycaemia hepatic core system of carbohydrate-triacylglycerol energy handling. The high probability of MS acting as a unique complex biological control system (essentially monophyletic) is presented, together with additional perspectives/considerations on the treatment of this 'very' human disease.

Intact ketogenesis predicted reduced risk of moderate-severe metabolic-associated fatty liver disease assessed by liver transient elastography in newly diagnosed type 2 diabetes

AIM

Hepatic ketogenesis is a key metabolic pathway that regulates energy homeostasis. Some related controversies exist regarding the pathogenesis of metabolic-associated fatty liver disease (MAFLD). We aimed to investigate whether intact ketogenic capacity could reduce the risk of MAFLD based on transient electrography (TE) in patients with newly diagnosed type 2 diabetes (T2D).

METHODS

A total of 361 subjects with newly diagnosed T2D were recruited and classified into two groups based on the median serum β-hydroxybutyrate (βHB) level, referred to as the intact and impaired ketogenesis groups. The glucometabolic relevance of ketogenic capacity and associations of the baseline serum β-HB and MAFLD assessed with TE were investigated.

RESULTS

Compared to the impaired ketogenesis group, the intact ketogenesis group showed better insulin sensitivity, lower serum triglyceride levels, and higher glycated hemoglobin levels. The controlled attenuation parameter (CAP) was lower in the intact ketogenesis group without statistical significance (289.7 ± 52.1 vs. 294.5 ± 43.6; p=0.342) but the prevalence of moderate-severe steatosis defined by CAP ≥260 dB/m was significantly lower in the intact group. Moreover, intact ketogenesis was significantly associated with a lower risk of moderate-severe MAFLD after adjusting for potential confounders (adjusted odds ratio 0.55, 95% confidence interval 0.30-0.98; p=0.044).

CONCLUSION

In drug-naïve, newly diagnosed T2D patients, intact ketogenesis predicted a lower risk of moderate-severe MAFLD assessed by TE.

Association between Impaired Ketogenesis and Metabolic-Associated Fatty Liver Disease

Metabolic (dysfunction) associated fatty liver disease (MAFLD) is generally developed with excessive accumulation of lipids in the liver. Ketogenesis is an efficient pathway for the disposal of fatty acids in the liver and its metabolic benefits have been reported. In this review, we examined previous studies on the association between ketogenesis and MAFLD and reviewed the candidate mechanisms that can explain this association.