Hepatic conversion of acetyl-CoA to acetate plays crucial roles in energy stress

Mechanisms of sepsis-induced acute liver injury: a comprehensive review

Sepsis is a severe, often life-threatening form of organ dysfunction that arises from an inappropriately regulated host response to infectious pathogen exposure. As the largest gland in the body, the liver serves as a regulatory hub for metabolic, immune, and detoxification activity. It is also an early sepsis target organ such that hepatic dysfunction is observed in 34-46% of patients with sepsis. The precise mechanisms that give rise to sepsis-induced liver injury, however, remain incompletely understood. Based on the research conducted to date, dysregulated systemic inflammation, microbial translocation, microcirculatory abnormalities, cell death, metabolic dysfunction, and liver inflammation may all contribute to the liver damage that can arise in the context of septicemia. This review was developed to provide an overview summarizing the potential mechanisms underlying sepsis-induced liver injury, informing the selection of potential targets for therapeutic intervention and providing a framework for the alleviation of patient symptoms and the improvement of prognostic outcomes.

Impact of Dapagliflozin on Hepatic Lipid Metabolism and a Dynamic Model of Ketone Body Levels

The rising prevalence of metabolic-associated steatotic liver disease emphasizes the need to understand its lipid metabolism. Dapagliflozin may improve hepatic steatosis but could also increase the risk of ketoacidosis by elevating β-hydroxybutyrate (KB) levels. This study investigates dapagliflozin's effects on hepatic lipid metabolism and quantifies KB levels in vivo. Male Sprague-Dawley rats were fed either a normal diet or a high-fat diet (HFD) for 12 weeks. The HFD rats were then divided into four subgroups to receive vehicle, 0.5 mg/kg, 1 mg/kg, and 3 mg/kg of dapagliflozin for four weeks. Free fatty acids (FFA) and KB levels were monitored, while protein and gene expression were analyzed. And a dynamic model of KB was developed for humans based on preclinical data. Dapagliflozin decreased body weight and visceral fat in HFD rats, increasing KB by upregulating CPT1a, HMGCS2, and HMGCL, and downregulating ACC. These changes correlated with reduced liver/fat index, liver pathology score, and oil-red staining area. A pharmacokinetic/pharmacodynamic (PK/PD) model was created from preclinical data to quantify KB levels in rats and validated in humans. Dapagliflozin reduces hepatic steatosis by enhancing fatty acid β-oxidation and ketogenesis and inhibiting fat synthesis. A dynamic model accurately predicts ketone body levels in treated individuals.

β cell acetate production and release are negligible

BACKGROUND

Studies suggest that short chain fatty acids (SCFAs), which are primarily produced from fermentation of fiber, regulate insulin secretion through free fatty acid receptors 2 and 3 (FFA2 and FFA3). As these are G-protein coupled receptors (GPCRs), they have potential therapeutic value as targets for treating type 2 diabetes (T2D). The exact mechanism by which these receptors regulate insulin secretion and other aspects of pancreatic β cell function is unclear. It has been reported that glucose-dependent release of acetate from pancreatic β cells negatively regulates glucose stimulated insulin secretion. While these data raise the possibility of acetate's potential autocrine action on these receptors, these findings have not been independently confirmed, and multiple concerns exist with this observation, particularly the lack of specificity and precision of the acetate detection methodology used.

METHODS

Using Min6 cells and mouse islets, we assessed acetate and pyruvate production and secretion in response to different glucose concentrations, via liquid chromatography mass spectrometry.

RESULTS

Using Min6 cells and mouse islets, we showed that both intracellular pyruvate and acetate increased with high glucose conditions; however, intracellular acetate level increased only slightly and exclusively in Min6 cells but not in the islets. Further, extracellular acetate levels were not affected by the concentration of glucose in the incubation medium of either Min6 cells or islets.

CONCLUSIONS

Our findings do not substantiate the glucose-dependent release of acetate from pancreatic β cells, and therefore, invalidate the possibility of an autocrine inhibitory effect on glucose stimulated insulin secretion.