SGLT2 inhibitor improves kidney function and morphology by regulating renal metabolism in mice with diabetic kidney disease.

BACKGROUND: Diabetic kidney disease (DKD) is a secondary complication of diabetes mellitus and a leading cause of chronic kidney disease. AIM: To investigate the impact of long-term canagliflozin treatment on DKD and elucidate its underlying mechanism. METHODS: DKD model was established using high-fat diet and streptozotocin in male C57BL/6J mice (n = 30). Mice were divided into five groups and treated for 12 weeks. 1) normal control mice, 2) DKD model, 3) mice treated low-dose of canagliflozin, 4) high-dose of canagliflozin and 5) ß-hydroxybutyrate. Mice kidney morphology and function were evaluated, and a metabolomics analysis was performed. RESULTS: Canagliflozin treatment reduced blood creatinine and urine nitrogen levels and improved systemic insulin sensitivity and glucose tolerance in diabetic mice. Additionally, a decrease in histological lesions including collagen and lipid deposition in the kidneys was observed. ß-hydroxybutyrate treatment did not yield a comparable outcome. The metabolomics analysis revealed that canagliflozin induced alterations in amino acid metabolism profiles in the renal tissue of diabetic mice. CONCLUSION: Canagliflozin protects the kidneys of diabetic mice by increasing the levels of essential amino acids, promoting mitochondrial homeostasis, mitigating oxidative stress, and stimulating the amino acid-dependent tricarboxylic acid cycle.

Effect of the ketone beta-hydroxybutyrate on markers of inflammation and immune function in adults with type 2 diabetes.

Pre-clinical and cell culture evidence supports the role of the ketone beta-hydroxybutyrate (BHB) as an immunomodulatory molecule that may inhibit inflammatory signalling involved in several chronic diseases such as type 2 diabetes (T2D), but studies in humans are lacking. Therefore, we investigated the anti-inflammatory effect of BHB in humans across three clinical trials. To investigate if BHB suppressed pro-inflammatory cytokine secretion, we treated LPS-stimulated leukocytes from overnight-fasted adults at risk for T2D with BHB (Study 1). Next (Study 2), we investigated if exogenously raising BHB acutely in vivo by ketone monoester supplementation (KME) in adults with T2D would suppress pro-inflammatory plasma cytokines. In Study 3, we investigated the effect of BHB on inflammation via ex vivo treatment of LPS-stimulated leukocytes with BHB and in vivo thrice-daily pre-meal KME for 14 days in adults with T2D. Ex vivo treatment with BHB suppressed LPS-stimulated IL-1ß, TNF-α, and IL-6 secretion and increased IL-1RA and IL-10 (Study 1). Plasma IL-10 increased by 90 min following ingestion of a single dose of KME in T2D, which corresponded to peak blood BHB (Study 2). Finally, 14 days of thrice-daily KME ingestion did not significantly alter plasma cytokines or leukocyte subsets including monocyte and T-cell polarization (Study 3). However, direct treatment of leukocytes with BHB modulated TNF-α, IL-1ß, IFN-γ, and MCP-1 secretion in a time- and glucose-dependent manner (Study 3). Therefore, BHB appears to be anti-inflammatory in T2D, but this effect is transient and is modulated by the presence of disease, glycaemia, and exposure time.

Comparison of insulin infusion protocols for management of canine and feline diabetic ketoacidosis.

OBJECTIVE: Describe the use of fixed-rate intravenous insulin infusions (FRIs) in cats and dogs with diabetic ketoacidosis (DKA) and determine if this is associated with faster resolution of ketosis compared to variable-rate intravenous insulin infusions (VRIs). Secondary objectives were to evaluate complication rates, length of hospitalization (LOH), and survival to discharge (STD). DESIGN: Randomized clinical trial (January 2019 to July 2020). SETTING: University veterinary teaching hospital and private referral hospital. ANIMALS: Dogs and cats with DKA and venous pH <7.3, blood glucose concentration >11 mmol/L (198 mg/dL), and ß-hydroxybutyrate (BHB) concentration >3 mmol/L were eligible for inclusion. Patients were randomly assigned to receive either FRI or VRI. INTERVENTIONS: Neutral (regular) insulin was administered IV as an FRI or VRI. For FRI, the rate was maintained at 0.01 IU/kg/h. For VRI, the dose was adjusted according to blood glucose concentration. MEASUREMENTS AND RESULTS: Sixteen cats and 20 dogs were enrolled. Population characteristics, mean insulin infusion rate, time to resolution of ketosis (BHB <0.6 mmol/L), complications, LOH, and STD were evaluated. In cats, overall resolution of ketosis was low (9/16 [56.3%]), limiting comparison of protocols. In dogs, resolution of ketosis was high (19/20 dogs [95.0%]) but the time to resolution in the FRI group was not different than that in the VRI group (P = 0.89), despite a 25% higher average insulin infusion rate in the FRI group (P = 0.04). The incidence of complications was low and did not differ between protocols. In cats, LOH and STD did not differ between protocols. All cats that died (5/16) did so within 78 hours and none had resolution of ketosis. Dogs receiving FRI had a shorter LOH (P = 0.01) but STD did not differ between protocols. Six dogs (30.0%) did not survive to hospital discharge but all had resolution of ketosis. CONCLUSIONS: FRIs can be used in veterinary species but may not hasten resolution of ketosis.

ß-hydroxybutyrate administered at reperfusion reduces infarct size and preserves cardiac function by improving mitochondrial function through autophagy in male mice.

Ischemia/reperfusion (I/R) injury after revascularization contributes ∼50% of infarct size and causes heart failure, for which no established clinical treatment exists. ß-hydroxybutyrate (ß-OHB), which serves as both an energy source and a signaling molecule, has recently been reported to be cardioprotective when administered immediately before I/R and continuously after reperfusion. This study aims to determine whether administering ß-OHB at the time of reperfusion with a single dose can alleviate I/R injury and, if so, to define the mechanisms involved. We found plasma ß-OHB levels were elevated during ischemia in STEMI patients, albeit not to myocardial protection level, and decreased after revascularization. In mice, compared with normal saline, ß-OHB administrated at reperfusion reduced infarct size (by 50%) and preserved cardiac function, as well as activated autophagy and preserved mtDNA levels in the border zone. Our treatment with one dose ß-OHB reached a level achievable with fasting and strenuous physical activity. In neonatal rat ventricular myocytes (NRVMs) subjected to I/R, ß-OHB at physiologic level reduced cell death, increased autophagy, preserved mitochondrial mass, function, and membrane potential, in addition to attenuating reactive oxygen species (ROS) levels. ATG7 knockdown/knockout abolished the protective effects of ß-OHB observed both in vitro and in vivo. Mechanistically, ß-OHB's cardioprotective effects were associated with inhibition of mTOR signaling. In conclusion, ß-OHB, when administered at reperfusion, reduces infarct size and maintains mitochondrial homeostasis by increasing autophagic flux (potentially through mTOR inhibition). Since ß-OHB has been safely tested in heart failure patients, it may be a viable therapeutic to reduce infarct size in STEMI patients.

Dapagliflozin Attenuates Heart Failure With Preserved Ejection Fraction Remodeling and Dysfunction by Elevating ß-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 ß-hydroxybutyric acid (ß-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 ß-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.

Beneficial Effects of Ketone Ester in Patients With Cardiogenic Shock: A Randomized, Controlled, Double-Blind Trial.

BACKGROUND: Cardiogenic shock (CS) is a life-threatening condition with sparse treatment options. The ketone body 3-hydroxybutyrate has favorable hemodynamic effects in patients with stable chronic heart failure. Yet, the hemodynamic effects of exogenous ketone ester (KE) in patients with CS remain unknown. OBJECTIVES: The authors aimed to assess the hemodynamic effects of single-dose enteral treatment with KE in patients with CS. METHODS: In a double-blind, crossover study, 12 patients with CS were randomized to an enteral bolus of KE and isocaloric, isovolumic placebo containing maltodextrin. Patients were assessed with pulmonary artery catheterization, arterial blood samples, echocardiography, and near-infrared spectroscopy for 3 hours following each intervention separated by a 3-hour washout period. RESULTS: KE increased circulating 3-hydroxybutyrate (2.9 ± 0.3 mmol/L vs 0.2 ± 0.3 mmol/L, P < 0.001) and was associated with augmented cardiac output (area under the curve of relative change: 61 ± 22 L vs 1 ± 18 L, P = 0.044). Also, KE increased cardiac power output (0.07 W [95% CI: 0.01-0.14]; P = 0.037), mixed venous saturation (3 percentage points [95% CI: 1-5 percentage points]; P = 0.010), and forearm perfusion (3 percentage points [95% CI: 0-6 percentage points]; P = 0.026). Right (P = 0.048) and left (P = 0.017) ventricular filling pressures were reduced whereas heart rate and mean arterial and pulmonary arterial pressures remained similar. Left ventricular ejection fraction improved by 4 percentage points (95% CI: 2-6 percentage points; P = 0.005). Glucose levels decreased by 2.6 mmol/L (95% CI: -5.2 to 0.0; P = 0.047) whereas insulin levels remained unaltered. CONCLUSIONS: Treatment with KE improved cardiac output, biventricular function, tissue oxygenation, and glycemic control in patients with CS (Treatment With the Ketone Body 3-hydroxybutyrate in Patients With Cardiogenic Shock [KETO-SHOCK1]; NCT04642768).

3-Hydroxybutyrate ameliorates sepsis-associated acute lung injury by promoting autophagy through the activation of GPR109α in macrophages.

BACKGROUND: Sepsis is a systemic inflammatory disease caused by multiple pathogens, with the most commonly affected organ being the lung. 3-Hydroxybutyrate plays a protective role in inflammatory diseases through autophagy promotion; however, the exact mechanism remains unexplored. METHOD: Our study used the MIMIC-III database to construct a cohort of ICU sepsis patients and figure out the correlation between the level of ketone bodies and clinical prognosis in septic patients. In vivo and in vitro models of sepsis were used to reveal the role and mechanism of 3-hydroxybutyrate in sepsis-associated acute lung injury (sepsis-associated ALI). RESULT: Herein, we observed a strong correlation between the levels of ketone bodies and clinical prognosis in patients with sepsis identified using the MIMIC- III database. In addition, exogenous 3-hydroxybutyrate supplementation improved the survival rate of CLP-induced sepsis in mice by promoting autophagy. Furthermore, 3-hydroxybutyrate treatment protected against sepsis-induced lung damage. We explored the mechanism underlying these effects. The results indicated that 3-hydroxybutyrate upregulates autophagy levels by promoting the transfer of transcription factor EB (TFEB) to the macrophage nucleus in a G-protein-coupled receptor 109 alpha (GPR109α) dependent manner, upregulating the transcriptional level of ultraviolet radiation resistant associated gene (UVRAG) and increasing the formation of autophagic lysosomes. CONCLUSION: 3-Hydroxybutyrate can serve as a beneficial therapy for sepsis-associated ALI through the upregulation of autophagy. These results may provide a basis for the development of promising therapeutic strategies for sepsis-associated ALI.

Ketones and the Heart: Metabolic Principles and Therapeutic Implications.

The ketone bodies beta-hydroxybutyrate and acetoacetate are hepatically produced metabolites catabolized in extrahepatic organs. Ketone bodies are a critical cardiac fuel and have diverse roles in the regulation of cellular processes such as metabolism, inflammation, and cellular crosstalk in multiple organs that mediate disease. This review focuses on the role of cardiac ketone metabolism in health and disease with an emphasis on the therapeutic potential of ketosis as a treatment for heart failure (HF). Cardiac metabolic reprogramming, characterized by diminished mitochondrial oxidative metabolism, contributes to cardiac dysfunction and pathologic remodeling during the development of HF. Growing evidence supports an adaptive role for ketone metabolism in HF to promote normal cardiac function and attenuate disease progression. Enhanced cardiac ketone utilization during HF is mediated by increased availability due to systemic ketosis and a cardiac autonomous upregulation of ketolytic enzymes. Therapeutic strategies designed to restore high-capacity fuel metabolism in the heart show promise to address fuel metabolic deficits that underpin the progression of HF. However, the mechanisms involved in the beneficial effects of ketone bodies in HF have yet to be defined and represent important future lines of inquiry. In addition to use as an energy substrate for cardiac mitochondrial oxidation, ketone bodies modulate myocardial utilization of glucose and fatty acids, two vital energy substrates that regulate cardiac function and hypertrophy. The salutary effects of ketone bodies during HF may also include extra-cardiac roles in modulating immune responses, reducing fibrosis, and promoting angiogenesis and vasodilation. Additional pleotropic signaling properties of beta-hydroxybutyrate and AcAc are discussed including epigenetic regulation and protection against oxidative stress. Evidence for the benefit and feasibility of therapeutic ketosis is examined in preclinical and clinical studies. Finally, ongoing clinical trials are reviewed for perspective on translation of ketone therapeutics for the treatment of HF.

Establishing Pragmatic Analytical Performance Specifications for Blood Beta-Hydroxybutyrate Testing.

BACKGROUND: Currently, no authoritative guidelines exist recommending the analytical performance specification (APS) of blood beta-hydroxybutyrate (BOHB) testing in order to meet the clinical needs of patients. This study has applied existing diabetic ketoacidosis (DKA) BOHB diagnostic thresholds and the recommended rates of fall in BOHB concentrations during DKA treatment to establish pragmatic APSs for BOHB testing. METHODS: Required analytical performance was based on 2 clinical requirements: (a) to reliably distinguish between non-adjacent DKA BOHB diagnostic categories of <0.6, 0.6 to 1.5, 1.6 to 2.9, and ≥3 mmol/L, and (b) to be assured that a measured 0.5 mmol/L reduction in BOHB indicates the true concentration is at least falling (meaning >0 mmol/L decline). RESULTS: An analytical coefficient of variation (CV) of <21.5% could reliably distinguish all non-adjacent diagnostic categories with >99% certainty, assuming zero bias. In contrast, within-day CVs of 4.9%, 7.0%, and 9.1% at 3 mmol/L BOHB were required to assure truly falling ketone concentrations with 99% (optimal), 95% (desirable), and 90% (minimal) probability, respectively. These CVs are larger at lower BOHB concentrations and smaller at higher concentrations. CONCLUSIONS: Reliable tracking of changes in BOHB during DKA treatment largely drives the requirement for analytical performance. These data can be used to guide minimal, desirable, and optimal performance targets for BOHB meters and laboratory assays.

GLUT inhibitor WZB117 induces cytotoxicity with increased production of amyloid-beta peptide in SH-SY5Y cells preventable by beta-hydroxybutyrate: implications in Alzheimer's disease.

BACKGROUND: Inhibitors of glucose transporters are being explored as potential anti-cancer drugs. Decreased cerebral glucose utilization with reduced levels of several glucose transporters is also an important pathogenic signature of neurodegeneration of Alzheimer's disease, but its exact role in the pathogenesis of this disease is not established. We explored in an experimental model if inhibitors of glucose transporters could lead to altered amyloid-beta homeostasis, mitochondrial dysfunction, and neuronal death, which are relevant in the pathogenesis of Alzheimer's disease. METHODS: SH-SY5Y cells (human neuroblastoma cell line) were exposed to an inhibitor (WZB117) of several types of glucose transporters. We examined the effects of glucose hypometabolism on SH-SY5Y cells in terms of mitochondrial functions, production of reactive oxygen species, amyloid-beta homeostasis, and neural cell death. The effect of ß-hydroxybutyrate in ameliorating the effects of WZB117 on SH-SY5Y cells was also examined. RESULTS: We observed that exposure of SH-SY5Y cells to WZB117 caused mitochondrial dysfunction, increased production of reactive oxygen species, loss of cell viability, increased expression of BACE 1, and intracellular accumulation of amyloid ß peptide (Aß42). All the effects of WZB117 could be markedly prevented by co-treatment with ß-hydroxybutyrate. Cyclosporine A, a blocker of mitochondrial permeability transition pore (mPTP) activation, could not prevent cell death caused by WZB117. CONCLUSION: Results in this neuroblastoma model have implications for the pathogenesis of Alzheimer's disease and warrant further explorations of WZB117 in primary cultures of neurons and experimental animal models.

Diabetic Ketoalkalosis: A Common Yet Easily Overlooked Alkalemic Variant of Diabetic Ketoacidosis Associated with Mixed Acid-Base Disorders.

BACKGROUND: Diabetic ketoacidosis (DKA) is commonly complicated by mixed acid-base disorders. Therefore, patients with DKA can present with pH > 7.3 or bicarbonate > 18 mmol/L, which falls outside the values defined by the current traditional DKA criteria (pH ≤ 7.3 or bicarbonate ≤ 18 mmol/L). OBJECTIVE: We aimed to study the spectrum of acid-base clinical presentations of DKA and the prevalence of diabetic ketoalkalosis. METHODS: This study included all adult patients at a single institution admitted in 2018-2020 with diabetes, positive beta-hydroxybutyric acid, and increased anion gap ≥ 16 mmol/L. Mixed acid-base disorders were analyzed to determine the spectrum of presentation of DKA. RESULTS: There were 259 encounters identified under the inclusion criteria. Acid-base analysis was available in 227 cases. Traditional acidemic DKA (pH ≤ 7.3), DKA with mild acidemia (7.3 < pH ≤ 7.4), and diabetic ketoalkalosis (pH > 7.4) account for 48.9% (111/227), 27.8% (63/227), and 23.3% (53/227) of cases, respectively. Of the 53 cases with diabetic ketoalkalosis, increased anion gap metabolic acidosis was present in all, and concurrent metabolic alkalosis, respiratory alkalosis, and respiratory acidosis were present in 47.2% (25/53), 81.1% (43/53), and 11.3% (6/53) encounters, respectively. In addition, 34.0% (18/53) of those with diabetic ketoalkalosis were found to have severe ketoacidosis, defined by beta-hydroxybutyric acid ≥ 3 mmol/L. CONCLUSIONS: DKA can present as traditional acidemic DKA, DKA with mild acidemia, and diabetic ketoalkalosis. Diabetic ketoalkalosis is a common yet easily overlooked alkalemic variant of DKA associated with mixed acid-base disorders, and a high proportion of these presentations have severe ketoacidosis and thus, require the same treatment as traditional DKA.

D-beta-hydroxybutyrate protects against microglial activation in lipopolysaccharide-treated mice and BV-2 cells.

Microglial activation is a key event in neuroinflammation, which, in turn, is a central process in neurological disorders. In this study, we investigated the protective effects of D-beta-hydroxybutyrate (BHB) against microglial activation in lipopolysaccharide (LPS)-treated mice and BV-2 cells. The effects of BHB in mice were assessed using behavioral testing, morphological analysis and immunofluorescence labeling for the microglial marker ionizing calcium-binding adaptor molecule 1 (IBA-1) and the inflammatory cytokine interleukin-6 (IL-6) in the hippocampus. Moreover, we examined the levels of the inflammatory IL-6 and tumor necrosis factor-α (TNF-α), as well as those of the neuroprotective brain-derived neurotrophic factor (BDNF) and transforming growth factor-ß (TGF-ß) in the brain. In addition, we examined the effects of BHB on IL-6, TNF-α, BDNF, TGF-ß, reactive oxygen species (ROS) level and cell viability in LPS-stimulated BV-2 cells. BHB treatments attenuated behavioral abnormalities, reduced the number of IBA-1-positive cells and the intensity of IL-6 fluorescence in the hippocampus, with amelioration of microglia morphological changes in the LPS-treated mice. Furthermore, BHB inhibited IL-6 and TNF-α generation, but promoted BDNF and TGF-ß production in the brain of LPS-treated mice. In vitro, BHB inhibited IL-6 and TNF-α generation, increased BDNF and TGF-ß production, reduced ROS level, ameliorated morphological changes and elevated cell viability of LPS-stimulated BV-2 cells. Together, our findings suggest that BHB exerts protective effects against microglial activation in vitro and in vivo, thereby reducing neuroinflammation.

RESET-PKD: a pilot trial on short-term ketogenic interventions in autosomal dominant polycystic kidney disease.

BACKGROUND: Ketogenic dietary interventions (KDI) have been shown to be effective in animal models of polycystic kidney disease (PKD), but data from clinical trials are lacking. METHODS: Ten autosomal dominant PKD (ADPKD) patients with rapid disease progression were enrolled at visit V1 and initially maintained a carbohydrate-rich diet. At V2, patients entered one of the two KDI arms: a 3-day water fast (WF) or a 14-day ketogenic diet (KD). At V3, they resumed their normal diet for 3-6 weeks until V4. At each visit, magnetic resonance imaging kidney and liver volumetry was performed. Ketone bodies were evaluated to assess metabolic efficacy and questionnaires were used to determine feasibility. RESULTS: All participants [KD n = 5, WF n = 5; age 39.8 ± 11.6 years; estimated glomerular filtration rate 82 ± 23.5 mL/min/1.73 m2; total kidney volume (TKV) 2224 ± 1156 mL] were classified as Mayo Class 1C-1E. Acetone levels in breath and beta-hydroxybutyrate (BHB) blood levels increased in both study arms (V1 to V2 average acetone: 2.7 ± 1.2 p.p.m., V2 to V3: 22.8 ± 11.9 p.p.m., P = .0006; V1 to V2 average BHB: 0.22 ± 0.08 mmol/L, V2 to V3: 1.88 ± 0.93 mmol/L, P = .0008). Nine of 10 patients reached a ketogenic state and 9/10 evaluated KDIs as feasible. TKV did not change during this trial. However, we found a significant impact on total liver volume (ΔTLV V2 to V3: -7.7%, P = .01), mediated by changes in its non-cystic fraction. CONCLUSIONS: RESET-PKD demonstrates that short-term KDIs potently induce ketogenesis and are feasible for ADPKD patients in daily life. While TLV quickly changed upon the onset of ketogenesis, changes in TKV may require longer-term interventions.

ß-Hydroxybutyric acid upregulated by Suhuang antitussive capsule ameliorates cough variant asthma through GSK3ß/AMPK-Nrf2 signal axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Cough variant asthma (CVA) is a chronic inflammatory disease characterized by cough as the main symptom. Suhuang antitussive capsule (Suhuang), one of traditional Chinese patent medicines, mainly treats CVA clinically. Previous studies have shown that Suhuang significantly improved CVA, post-infectious cough (PIC), sputum obstruction and airway remodeling. However, the effect of Suhuang on ovalbumin-induced (OVA-induced) metabolic abnormalities in CVA is unknown. AIM OF THE STUDY: This study aimed to identify potential metabolites associated with efficacy of Suhuang in the treatment of CVA, and determined how Suhuang regulates metabolites, and differential metabolites reduce inflammation and oxidative stress. MATERIALS AND METHODS: Rats were given 1 mg OVA/100 mg aluminum hydroxide in the 1st and 7th days by intraperitoneal injection and challenged by atomizing inhalation of 1% OVA saline solution after two weeks to establish the CVA model. Rats were intragastrically (i.g.) administrated with Suhuang at 1.4 g/kg and ß-hydroxybutyric acid (ß-HB) were given with different concentrations (87.5 and 175 mg/kg/day) by intraperitoneal injection for 2 weeks. After 26 days, GC-MS-based metabolomic approach was applied to observe metabolic changes and search differential metabolites. The number of coughs, coughs latencies, enzyme-linked immunosorbent assay (ELISA), histological analysis and quantitative-polymerase chain reaction (Q-PCR) were used to investigate the effects of Suhuang. Then ß-HB on CVA rats, NLRP3 inflammasome and GSK3ß/AMPK/Nrf2 signalling pathway were detected by western blotting. RESULTS: The results showed that Suhuang treatment significantly enhanced the serum level of ß-HB. Interestingly, exposure to exogenous ß-HB was also protective against OVA-induced CVA. ß-HB significantly reduced the number of coughs and lengthened coughs latencies, improved lung injury, reduced the secretion of various cytokines, and directly inhibited the NLRP3 inflammasome. In addition, ß-HB increased the nuclear accumulation of Nrf2 by activating the GSK3ß/AMPK signaling axis, and then inactivating the NF-κB signaling pathway, effectively protecting OVA-induced CVA from oxidative stress and inflammation. CONCLUSIONS: The results of this study shows that ß-HB can reduce inflammation and oxidative stress, the increased production of ß-HB in serum might be the crucial factor for Suhuang to exert its effect in the treatment of CVA.

ß-Hydroxybutyrate alleviates pyroptosis in MPP+/MPTP-induced Parkinson's disease models via inhibiting STAT3/NLRP3/GSDMD pathway.

BACKGROUND: Parkinson's disease (PD) is a common neurodegenerative disease characterized by motor symptoms and non-motor symptoms, and affects millions of people worldwide. Growing evidence implies ß-Hydroxybutyrate (BHB), one of the ketone bodies generated by ketogenesis, plays a neuroprotective role in neurodegenerative diseases. We aimed to verify the anti-inflammatory effect of BHB on PD and further explore potential molecular mechanisms. METHODS: We performed the experiments on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice model in vivo and 1-methyl-4-phenylpyridinium (MPP+)-simulated BV2 cell model in vitro, with or without BHB pretreatment. Motor function was assessed by pole test, forced swimming test, traction test and open field test. Immunofluorescence was used to evaluate the loss of dopaminergic neurons and glial cell activation in MPTP-induced PD model mice. The expression of the STAT3/NLRP3/GSDMD signal pathway was measured by western blots. Proinflammatory cytokines was assessed by enzyme-linked immunosorbent assay (ELISA). RESULTS: BHB treatment reversed motor deficits, loss of dopaminergic neurons and glial cell activation in PD mice induced by MPTP. Moreover, BHB inhibited microglia pyroptosis by negatively regulating STAT3/NLRP3/GSDMD signal pathway, resulting in downregulation of proinflammatory cytokines (IL-1ß and IL-18) in vivo and vitro. CONCLUSION: These data suggested BHB supplement inhibited pyroptosis by down-regulating STAT3-mediated NLRP3 inflammasome activation for PD models in vivo and in vitro. Our findings provided novel insights and available interventions for the prevention and treatment of PD, and highlighted pyroptosis as a potential therapeutic target for PD.

A randomized, double-blind, clinical pilot trial of adjunct ketone supplement compared to placebo for treating posttraumatic stress disorder.

BACKGROUND: Despite some evidence of the helpful role of ketones in some neuropsychiatric disorders, there are no clinical trials that examine these agents for posttraumatic stress disorder (PTSD). Our aim was to investigate whether ketone salt supplementation can improve PTSD symptoms in a randomized, placebo-controlled trial. METHODS: A total of 21 participants were recruited and randomized to placebo or ketone supplement. Each dose of ketone supplement included 7 g of ketones in the form of beta-hydroxybutyrate for a total of 14 g/d. Data were collected through questionnaires to assess PTSD symptoms. We used Fisher's exact tests for categorical variables and 2-sample t tests for continuous variables to examine differences in baseline values between treatment groups. Mixed models were employed to examine changes over time between groups on the PTSD Checklist for DSM-5 (PCL-5). RESULTS: There were no statistically significant differences in PCL-5 medians between the ketone and control groups at pretest (P = 1.0000) or post-test (P = .6020). The ketone group had a statistically significant decrease in median PCL-5 scores from 58.5 (pretest) to 54.0 (posttest; P = .0003) but the control group did not change (34 at pretest and at posttest; P = .4418). CONCLUSIONS: The ketone group showed a significant decrease in PCL-5 score at posttest compared with pretest that was not seen in the control group, although these changes were not statistically significant between groups. The small sample size limited the study and likely contributed to the lack of significance. Larger trials are needed to more definitively examine these findings.

Exogenous ketone ester administration attenuates systemic inflammation and reduces organ damage in a lipopolysaccharide model of sepsis.

AIMS: Sepsis is a life-threatening condition of organ dysfunction caused by dysregulated inflammation which predisposes patients to developing cardiovascular disease. The ketone ß-hydroxybutyrate is reported to be cardioprotective in cardiovascular disease and this may be due to their signaling properties that contribute to reducing inflammation. While exogenous ketone esters (KE) increase blood ketone levels, it remains unknown whether KEs can reduce the enhanced inflammatory response and multi-organ dysfunction that is observed in sepsis. Thus, this study assesses whether a recently developed and clinically safe KE can effectively improve the inflammatory response and organ dysfunction in sepsis. METHODS AND RESULTS: To assess the anti-inflammatory effects of a KE, we utilized a model of lipopolysaccharide (LPS)-induced sepsis in which an enhanced inflammatory response results in multi-organ dysfunction. Oral administration of KE for three days prior to LPS-injection significantly protected mice against the profound systemic inflammation compared to their vehicle-treated counterparts. In assessing organ dysfunction, KE protected mice from sepsis-induced cardiac dysfunction as well as renal dysfunction and fibrosis. Furthermore, KE administration attenuated the sepsis-induced inflammation in the heart, kidney, and liver. Moreover, these protective effects occurred independent of changes to enzymes involved in ketone metabolism. CONCLUSION: These data show that the use of an exogenous KE attenuates the dysregulated systemic and organ inflammation as well as organ dysfunction in a model of severe inflammation. We postulate that this exogenous KE is an appealing and promising approach to capitalize on the protective anti-inflammatory effects of ketones in sepsis and/or other inflammatory responses.

Changes in the rumen microbiota community in ketosis cows during propylene glycol treatment.

Ketosis, a common metabolic disorder in dairy cattle, occurs during early lactation and leads to higher concentrations of non-esterified fatty acids (NEFAs) and ß-hydroxybutyrate (BHBA), and is generally believed to be caused by excessive negative energy balance (NEB). Propylene glycol (PG), a gluconeogenic precursor, has been proved to promote gluconeogenesis and alleviate NEB. Oral administration of PG is widely considered one of the most effective therapeutic options for treating ketosis. Thus, in this study, we assessed the effects of PG on rumen microbiota via 16S rDNA analysis. The results show that one dose (500 mL) of PG treatment could rapidly reduce the blood BHBA level in ketosis cows by increasing the level and proportion of propionate in the rumen. Meanwhile, PG also had certain effects on the rumen bacterial community. Compared with before treatment, the relative abundances of Prevotella, Succinivibrionaceae_UCG-001 and Prevotellaceae_UCG-001 increased significantly, while those of Christensenellaceae_R-7_group, Butyrivibrio and Saccharofermentans significantly decreased. LEfSe analysis revealed that after PG treatment, only Rikenellaceae_RC9_gut_group was enriched in the rumen fluid at the genus level. In conclusion, the present study indicates that ketosis is accompanied by alterations in the rumen microbiota community. PG treatment changes the composition of rumen microbiota to a healthier state and contributes to rapid recovery from ketosis. These results support the usage of PG for treating such metabolic diseases that challenge high-yield cows due to their minimized cost and maximized safety without any adverse events.

ß-Hydroxybutyrate Improves Mitochondrial Function After Transient Ischemia in the Mouse.

ß-Hydroxybutyrate (BHB) is a ketone body formed in high amounts during lipolysis and fasting. Ketone bodies and the ketogenic diet were suggested as neuroprotective agents in neurodegenerative disease. In the present work, we induced transient ischemia in mouse brain by unilaterally occluding the middle cerebral artery for 90 min. BHB (30 mg/kg), given immediately after reperfusion, significantly improved the neurological score determined after 24 h. In isolated mitochondria from mouse brain, oxygen consumption by the complexes I, II and IV was reduced immediately after ischemia but recovered slowly over 1 week. The single acute BHB administration after reperfusion improved complex I and II activity after 24 h while no significant effects were seen at later time points. After 24 h, plasma and brain BHB concentrations were strongly increased while mitochondrial intermediates (citrate, succinate) were unchanged in brain tissue. Our data suggest that a single administration of BHB may improve mitochondrial respiration for 1-2 days but not for later time points. Endogenous BHB formation seems to complement the effects of exogenous BHB administration.

Ketone body ß-hydroxybutyrate ameliorates colitis by promoting M2 macrophage polarization through the STAT6-dependent signaling pathway.

BACKGROUND: Ketone body ß-hydroxybutyrate (BHB) has received more and more attentions, because it possesses a lot of beneficial, life-preserving effects in the fields of clinical science and medicine. However, the role of BHB in intestinal inflammation has not yet been investigated. METHODS: Colonic mucosa of inflammatory bowel disease (IBD) patients and healthy controls were collected for evaluation of BHB level. Besides, the therapeutic effect of exogenous BHB in a murine model of acute dextran sulfate sodium (DSS)-induced colitis were assessed by body weight change, colon length, disease activity index, and histopathological sections. The regulatory effectors of BHB were analyzed by RT-qPCR, immunofluorescence, and microbe analysis in vivo. Moreover, the molecular mechanism of BHB was further verified in bone marrow-derived macrophages (BMDMs). RESULTS: In this study, significantly reduced BHB levels were found in the colonic mucosa from IBD patients and correlated with IBD activity index. In addition, we demonstrated that the administration of exogenous BHB alleviated the severity of acute experimental colitis, which was characterized by less weight loss, disease activity index, colon shortening, and histology scores, as well as decreased crypt loss and epithelium damage. Furthermore, BHB resulted in significantly increased colonic expression of M2 macrophage-associated genes, including IL-4Ra, IL-10, arginase 1 (Arg-1), and chitinase-like protein 3, following DSS exposure, suggesting an increased M2 macrophage skewing in vivo. Moreover, an in vitro experiment revealed that the addition of BHB directly promoted STAT6 phosphorylation and M2 macrophage-specific gene expression in IL-4-stimulated macrophages. Besides, we found that BHB obviously increased M2 macrophage-induced mucosal repair through promoting intestinal epithelial proliferation. However, the enhancement effect of BHB on M2 macrophage-induced mucosal repair and anti-inflammation was completely inhibited by the STAT6 inhibitor AS1517499. CONCLUSIONS: In summary, we show that BHB promotes M2 macrophage polarization through the STAT6-dependent signaling pathway, which contributes to the resolution of intestinal inflammation and the repair of damaged intestinal tissues. Our finding suggests that exogenous BHB supplement may be a useful therapeutic approach for IBD treatment.