Hepatic Glycogen Depletion Research Articles

MiR-141/200c contributes to ethanol-mediated hepatic glycogen metabolism

ObjectiveHepatic glucose metabolism is profoundly perturbed by excessive alcohol intake. miR-141/200c expression is significantly induced by chronic ethanol feeding. This study aimed at identifying the role of miR-141/200c in glucose homeostasis during chronic ethanol exposure. MethodsWT and miR-141/200c KO mice were fed a control or an ethanol diet for 30 days, followed by a single binge of maltose dextrin or ethanol, respectively. Untargeted metabolomics analysis of hepatic primary metabolites was performed along with analyses for liver histology, gene expression, intracellular signaling pathways, and physiological relevance. Primary hepatocytes were used for mechanistic studies. ResultsmiR-141/200c deficiency rewires hepatic glucose metabolism during chronic ethanol feeding, increasing the abundance of glucose intermediates including G6P, an allosteric activator for GS. miR-141/200c deficiency replenished glycogen depletion during chronic ethanol feeding accompanied by reduced GS phosphorylation in parallel with increased expression of PP1 glycogen targeting subunits. Moreover, miR-141/200c deficiency prevented ethanol-mediated increases in AMPK and CaMKK2 activity. Ethanol treatment reduced glycogen content in WT-hepatocytes, which was reversed by dorsomorphin, a selective AMPK inhibitor, while KO-hepatocytes displayed higher glycogen content than WT-hepatocytes in response to ethanol treatment. Furthermore, treatment of hepatocytes with A23187, a calcium ionophore activating CaMKK2, lowered glycogen content in WT-hepatocytes. Notably, the suppressive effect of A23187 on glycogen deposition was reversed by dorsomorphin, demonstrating that the glycogen depletion by A23187 is mediated by AMPK. KO-hepatocytes exhibited higher glycogen content than WT-hepatocytes in response to A23187. Finally, miR-141/200c deficiency led to improved glucose tolerance and insulin sensitivity during chronic ethanol feeding. ConclusionsmiR-141/200c deficiency replenishes ethanol-mediated hepatic glycogen depletion through the regulation of GS activity and calcium signaling coupled with the AMPK pathway, improving glucose homeostasis and insulin sensitivity. These results underscore miR-141/200c as a potential therapeutic target for the management of alcohol intoxication.

Oreo Cookie Treatment Lowers LDL Cholesterol More Than High-Intensity Statin therapy in a Lean Mass Hyper-Responder on a Ketogenic Diet: A Curious Crossover Experiment.

Recent research has identified a unique population of 'Lean Mass Hyper-Responders' (LMHR) who exhibit increases in LDL cholesterol (LDL-C) in response to carbohydrate-restricted diets to levels ≥ 200 mg/dL, in association with HDL cholesterol ≥ 80 mg/dL and triglycerides ≤ 70 mg/dL. This triad of markers occurs primarily in lean metabolically healthy subjects, with the magnitude of increase in LDL-C inversely associated with body mass index. The lipid energy model has been proposed as one explanation for LMHR phenotype and posits that there is increased export and subsequent turnover of VLDL to LDL particles to meet systemic energy needs in the setting of hepatic glycogen depletion and low body fat. This single subject crossover experiment aimed to test the hypothesis that adding carbohydrates, in the form of Oreo cookies, to an LMHR subject on a ketogenic diet would reduce LDL-C levels by a similar, or greater, magnitude than high-intensity statin therapy. The study was designed as follows: after a 2-week run-in period on a standardized ketogenic diet, study arm 1 consisted of supplementation with 12 regular Oreo cookies, providing 100 g/d of additional carbohydrates for 16 days. Throughout this arm, ketosis was monitored and maintained at levels similar to the subject's standard ketogenic diet using supplemental exogenous d-β-hydroxybutyrate supplementation four times daily. Following the discontinuation of Oreo supplementation, the subject maintained a stable ketogenic diet for 3 months and documented a return to baseline weight and hypercholesterolemic status. During study arm 2, the subject received rosuvastatin 20 mg daily for 6 weeks. Lipid panels were drawn water-only fasted and weekly throughout the study. Baseline LDL-C was 384 mg/dL and reduced to 111 mg/dL (71% reduction) after Oreo supplementation. Following the washout period, LDL-C returned to 421 mg/dL, and was reduced to a nadir of 284 mg/dL with 20 mg rosuvastatin therapy (32.5% reduction). In conclusion, in this case study experiment, short-term Oreo supplementation lowered LDL-C more than 6 weeks of high-intensity statin therapy in an LMHR subject on a ketogenic diet. This dramatic metabolic demonstration, consistent with the lipid energy model, should provoke further research and not be seen as health advice.

Zinc-Phthalocyanine Loaded PLGA-PVA-Chitosan Nanosystem for the Enhancement of Antidiabetic Activity.

Zinc, one of the most common nutraceutical agents, proved to be effective for diabetes as it regulates the blood glucose level by inhibiting glucagon secretion. However, the hepatotoxicity of zinc creates necrosis, hepatic glycogen depletion, and apoptosis of hepatocytes at the concentration of 10 μg/kg. Phthalocyanine, a blue-colored compound, is an aromatic macrocyclic compound with good antioxidant ability owing to its heterocyclic nitrogen conjugation. The conjugation of zinc with phthalocyanine aimed to reduce the toxicity associated with zinc and enhance the antidiabetic activity at a lower dose. Hence, the present research work possessed the insights of the synthetic aspect of zinc with phthalocyanine along with its entrapment in the poly(lactic-co-glycolic acid) (PLGA)-chitosan nanosystem via oral administration in the treatment of diabetes. A nanoprecipitation technique was implemented for the synthesis of PLGA chitosan nanoparticles, and formulation was further optimized using a central composite design. Twenty trials provided by the software selected optimum concentrations of PLGA, poly(vinyl alcohol) (PVA), and chitosan in consideration with particle size up to 335.6 nm, zeta potential 27.87 mV, and entrapment efficiency of 75.67 ± 8.13%. Addition of chitosan to the nanocarrier system for controlling the release of the drug for 3 days was accompanied by the improvement in the glucose level within 28 days. The delivery of the nanoparticles showed enhancement in the cholesterol, triglyceride, alkaline phosphatase (ALP), urine parameters, and pro-inflammatory cytokines. The application of DoE (design of experiments) for the optimization of the nanoparticles established a controlled release formulation for diabetes, which displayed safety and effectiveness in streptozotocin (STZ)-induced diabetic rats.

A prolonged fast improves overnight substrate oxidation without modulating hepatic glycogen in adults with and without nonalcoholic fatty liver: A randomized crossover trial

Increasing overnight fasting time seems a promising strategy to improve metabolic health in individuals with nonalcoholic fatty liver (NAFL). Mechanisms underlying the beneficial effects of fasting may be related to larger fluctuations in hepatic glycogen and higher fat oxidation. This study investigated whether prolonging an overnight fast depletes hepatic glycogen stores and improves substrate metabolism in individuals with NAFL and healthy lean individuals. Eleven individuals with NAFL and ten control individuals participated in this randomized crossover trial. After a 9.5-hour or 16-hour fast, hepatic glycogen was measured by using carbon-13 magnetic resonance spectroscopy, and a meal test was performed. Nocturnal substrate oxidation was measured with indirect calorimetry. Extending fasting time led to lower nocturnal carbohydrate oxidation and higher fat oxidation in both groups (intervention × time, p < 0.005 for carbohydrate and fat oxidation). In both arms, the respiratory exchange ratio measured during the night remained higher in the group with NAFL compared with the control group (population p < 0.001). No changes were observed in hepatic glycogen depletion with a prolonged overnight fast in the group with NAFL or the control group. These results suggest that acutely prolonging the overnight fast can improve overnight substrate oxidation and that these alterations are not mediated by changes in hepatic glycogen depletion.

Inhalation Exposure to Airborne PM2.5Induces Integrated Organelle Stress Response in the Liver

Air pollution is a sustained problem of public health for the general population. Accumulating evidence has confirmed a significant association between exposure to fine ambient particulate matter with aerodynamic diameters &lt; 2.5 μm (PM2.5) and the increase of morbidity and mortality associated with cardiovascular and metabolic diseases. Chronic inflammation and dysregulated energy metabolism have been identified as the driving force of the PM2.5‐caused pathogenesis. However, a precise understanding of the molecular and cellular mechanisms by which PM2.5induces inflammatory stress responses and impairs energy homeostasis remains elusive. Research in our laboratory has addressed the mechanistic basis underlying the pathophysiologic effects of PM2.5exposure on liver and adipose tissues with mouse models under inhalation exposure to environmentally relevant PM2.5. Proteomics analysis with PM2.5‐exposed mouse liver tissues indicated that mitochondria and endoplasmic reticulum (ER) are the most sensitive organelles in transducing signaling cascades upon PM2.5stimulation. Further investigation revealed that inhalation exposure to PM2.5induces an integrated ER stress and mitochondrial stress response in mouse livers. Under PM2.5exposure, the ER and mitochondria interact and build up a platform through Mitochondria‐Associated Membranes (MAMs) to augment an integrated inflammatory stress response, mediated through the primary ER stress sensor IRE1α and Toll‐like receptor (TLR) 2 and 4. This integrated organelle stress response pathway promoted non‐alcoholic steatohepatitis (NASH), characterized by hepatic inflammation, steatosis and fibrogenesis, hepatic glycogen depletion, and insulin resistance in PM2.5‐exposed mice. Disruption of MAMs by knockdown of the MAM‐residing ER chaperone Sigma‐1 Receptor (Sig‐1R) or mitofusin (MNF2) in Kupffer cells or hepatocytes suppressed PM2.5‐induced NASH and insulin resistance in mice. Together, our studies suggested that exposure to airborne PM2.5pollution activates an integrated ER and mitochondrial stress response in the liver, which promotes NASH, disrupts energy homeostasis, and impairs insulin signaling associated with the development of metabolic syndrome. These findings provide significant insights into the hepatic pathways underlying PM2.5‐triggered liver pathology, and have important implications in the understanding, prevention, and treatment of air pollution‐associated metabolic disease.

Understanding risks and consequences of pathogen infections on the physiological performance of outmigrating Chinook salmon.

The greatest concentration of at-risk anadromous salmonids is found in California (USA)—the populations that have been negatively impacted by the degradation of freshwater ecosystems. While climate-driven environmental changes threaten salmonids directly, they also change the life cycle dynamics and geographic distribution of pathogens, their resulting host-pathogen interactions and potential for disease progression. Recent studies have established the correlation between pathogen detection and salmonid smolt mortality during their migration to the ocean. The objective of the present study was to screen for up to 47 pathogens in juvenile Chinook salmon (Oncorhynchus tshawytscha) that were held in cages at two key sites of the Sacramento River (CA, USA) and measure potential consequences on fish health. To do so, we used a combination of transcriptomic analysis, enzymatic assays for energy metabolism and hypoxia and thermal tolerance measures. Results revealed that fish were infected by two myxozoan parasites: Ceratonova shasta and Parvicapsula minibicornis within a 2-week deployment. Compared to the control fish maintained in our rearing facility, infected fish displayed reduced body mass, depleted hepatic glycogen stores and differential regulation of genes involved in the immune and general stress responses. This suggests that infected fish would have lower chances of migration success. In contrast, hypoxia and upper thermal tolerances were not affected by infection, suggesting that infection did not impair their capacity to cope with acute abiotic stressors tested in this study. An evaluation of long-term consequences of the observed reduced body mass and hepatic glycogen depletion is needed to establish a causal relationship between salmon parasitic infection and their migration success. This study highlights that to assess the potential sublethal effects of a stressor, or to determine a suitable management action for fish, studies need to consider a combination of endpoints from the molecular to the organismal level.

ULTRASOUND MEASUREMENT OF TRANSCEREBELLAR DIAMETER (TCD)/ABDOMINAL CIRCUMFERENCE (AC) RATIO IN NORMAL AND GROWTH RESTRICTED FETUSES ABOVE TWENTY WEEKS OF GESTATION

Background: Intrauterine growth retardation (IUGR) is an obstetrical syndrome that is generally associated with increased mortality and morbidity. In IUGR, maternal placental blood flow is extremely compromised and that worsen the inter-villous circulation leading to an end-stage fetal distress. Objective: To compare TCD/AC ratio in both normal and growth restricted fetuses in second and third trimesters and to find if there is any correlation between TCD/AC ratio and EFW. Patients and methods: The study was conducted on 100 singleton pregnant women at EL-Sayed Galal University Hospital and Damanhour Teaching Hospital in the period between March 2019 till May 2020 and the patients were divided into two main equal groups. Group I included pregnant females with normally growing fetuses and Group II included pregnant females with growth restricted fetuses above 20 weeks of gestation. Results: This study demonstrated the usefulness of the single cut-off value (13.75%) of the TCD/AC ratio which may contribute to the early identification of SGA infants. The problem lied in identifying the process at the onset or before the IUGR has become severe. Usually the first parameter to decrease is the fetal AC due to depletion of hepatic glycogen and subcutaneous fat stores. The TCD/AC ratio, which utilized a single cut-off value (13.75%) independent of GA, improved diagnostic sensitivity and specificity in these cases. The possible contribution of the TCD/AC ratio in identifying the fetal growth failure itself, which was more important than predicting weight at birth to be further evaluated. There was no correlation between TCD/AC ratio and EFW and no statistical significant correlation between TCD/AC ratio and UA Doppler. Conclusion: In IUGR fetuses, the fetal TCD was less affected than fetal head circumference (HC) suggesting preferential preservation of cerebellar growth relative to other cranial structures. The TCD/AC ratio was helpful in recognizing abnormal fetal growth even when the GA was uncertain since this ratio was gestational age-independent.

Role of GPRC6A in Regulating Hepatic Energy Metabolism in Mice

GPRC6A is a widely expressed G-protein coupled receptor that regulates energy metabolism. Global deletion of Gprc6a in mice is reported to result in a metabolic syndrome-like phenotype and conditional deletion of Gprc6a in pancreatic β-cell and skeletal muscle respectively impair insulin secretion and glucose uptake. In the current study, we explore the hepatic functions of GPRC6A by conditionally deleting Gprc6a in hepatocytes by cross breeding Alb-Cre and Gprc6aflox/flox mice to obtain Gprc6aLiver-cko mice. Gprc6aLiver-cko mice on a normal diet showed excessive hepatic fat accumulation and glycogen depletion. These mice also exhibit impaired glucose and pyruvate tolerance, but normal insulin sensitivity. Decreased circulating FGF-21 levels and FGF-21 message expression in the liver were found in Gprc6aLiver-cko mice. Hepatic transcriptome analysis identified alterations in multiple pathways regulating glucose, fat and glycogen metabolism in Gprc6aLiver-cko mice. Taken together, our studies suggest that GPRC6A directly regulates hepatic metabolism as well as regulates the production and release of FGF-21 to control systemic energy homeostasis. GPRC6A’s unique regulation of β-cell, skeletal muscle and hepatic function may represent a new therapeutic target for treating disordered energy metabolism metabolic syndrome and type 2 diabetes.

Carnitine Palmitoyl Transferase, Type 1A (CPT1A)

Carnitine Palmitoyl Transferase 1A (CPT1A) is a crucial enzyme needed for mitochondrial fatty acid oxidation and is fundamental for appropriate metabolic responses to prolonged fasting. Under normal conditions, the human body guarantees a constant energy supply, by metabolizing glucose in the short term and by oxidizing fatty acids into ketones during long term fasting or starvation. Fasting induces breakdown of the hepatic glycogen supply into glucose. Continued fasting eventually leads to glycogen depletion followed by a decrease in serum glucose and insulin levels, this decrease then activates hormone-sensitive lipases located in adipose tissues and causes the release of free fatty acids into the blood. Normally these free fatty acids would undergo beta-oxidation to produce energy, but CPT1A deficiency results in an 80% decrease in the activity of the CPT1A enzyme, leading to significant hepatic glycogen depletion and the inability to utilize ketones during periods of fasting. Preoperative fasting in these patients may result in vomiting, lethargy, hypoketotic hypoglycemia, seizures, liver failure, increased risk for infectious illnesses and higher rates of respiratory illnesses, placing this population at greater perioperative risk for anesthesia and surgery. Interventions include, but are not limited to, parent education and prevention techniques, recognition of symptoms, prompt treatment with glucose and even surgery cancellation. CPT1A deficiency is found in circum-arctic populations such as Alaskan Inupiat and Yupik, Canadian and Greenland Inuit, and Siberian Yupik and is thus known as the “Arctic Variant” of CPT1A. Once thought of as a rare disorder, the introduction of tandem mass spectrometry (MS/MS) to Alaska newborn screenings in 2003 revealed that the polymorphism c.1436C&gt;T variant in the CPT1A gene has an incidence as high as 80% in specific regions of Alaska. As of 2011, an estimated 700 Alaska Native Infants born each year are homozygous for the c.1436C&gt;T Arctic Variant. It is therefore important for anesthesia professionals in Alaska and other arctic regions to understand what CPT1A Arctic Variant is, and its implications for these patients in the perioperative period.

Oral ethinylestradiol-levonorgestrel normalizes fructose-induced hepatic lipid accumulation and glycogen depletion in female rats.

The present study investigated the effects of oral ethinylestradiol-levonorgestrel (EEL) on hepatic lipid and glycogen contents during high fructose (HF) intake, and determined whether pyruvate dehydrogenase kinase-4 (PDK-4) and glucose-6-phosphate dehydrogenase (G6PD) activity were involved in HF and (or) EEL-induced hepatic dysmetabolism. Female Wistar rats weighing 140-160 g were divided into groups. The control, EEL, HF, and EEL+HF groups received water (vehicle, p.o.), 1.0 μg ethinylestradiol plus 5.0 μg levonorgestrel (p.o.), fructose (10% w/v), and EEL plus HF, respectively, on a daily basis for 8 weeks. Results revealed that treatment with EEL or HF led to insulin resistance, hyperinsulinemia, increased hepatic uric acid production and triglyceride content, reduced glycogen content, and reduced production of plasma or hepatic glutathione- and G6PD-dependent antioxidants. HF but not EEL also increased fasting glucose and hepatic PDK-4. Nonetheless, these alterations were attenuated by EEL in HF-treated rats. Our results demonstrate that hepatic lipid accumulation and glycogen depletion induced by HF is accompanied by increased PDK-4 and defective G6PD activity. The findings also suggest that EEL would attenuate hepatic lipid accumulation and glycogen depletion by suppression of PDK-4 and enhancement of a G6PD-dependent antioxidant barrier.

Role of GPRC6A in Regulating Hepatic Energy Metabolism

We show that GPRC6A, an osteocalcin-sensing G-protein coupled receptor GPRC6A, uniquely regulates glucose and fatty acid metabolism in the liver. Conditional deletion of GPRC6A in hepatocytes results in hepatic fat accumulation and glycogen depletion associated with impaired glucose and pyruvate tolerance and suppression of FGF-21 in mice. Conversely, knock-in of a human KGKY gain-of-function polymorphism in the 3rd intracellular loop of GPRC6A, in mice results in reduced blood glucose associated with improved glucose, insulin and pyruvate tolerance and increased FGF-21. Hepatic transcriptome analysis shows that GPRC6A has counter regulatory effects on fatty acid oxidation and synthesis and glycolysis and gluconeogenesis, and concordant effects on glycogenesis and glycogenolysis. Taken together, our studies suggest that the level of GPRC6A activation determines how glucose and FAs are utilized by the liver. GPRC6A may be a new therapeutic target for treating metabolic syndrome and its complications.

Dysregulation of Lipid Metabolism during Gram-Negative Sepsis in Mkp-1 Deficient Mice

Abstract Mitogen-activated protein kinase phosphatase (Mkp)-1 exerts its anti-inflammatory activities during Gramnegative sepsis by deactivating p38 and JNK. We have previously shown that Mkp-1+/+ mice, but not Mkp-1−/− mice, exhibit hypertriglyceridemia and hepatic glycogen depletion during severe sepsis. However, the regulation of hepatic lipid stores and the underlying mechanism of lipid dysregulation during sepsis remains an enigma. To understand the molecular mechanism underlying the sepsis-associated metabolic changes and the role of Mkp-1 in the process, we infected Mkp-1+/+ and Mkp-1−/− mice with Escherichia coli i.v., and assessed the effects of Mkp-1 deficiency on tissue lipid contents. We also examined global gene expression profile by RNA-seq in the livers. We found that in the absence of E. coli infection, Mkp-1 deficiency decreased liver triglyceride levels. Upon E. coli infection, Mkp-1+/+ mice, but not Mkp-1−/− mice, developed hepatocyte ballooning and increased lipid deposition in the livers. E. coli infection caused profound changes in gene expression profile of a large number of proteins that regulate lipid metabolism in wildtype mice, while these changes were substantially disrupted in Mkp-1−/− mice. Interestingly, in Mkp-1+/+ mice E. coli infection resulted in down-regulation of genes that facilitate fatty acid synthesis but upregulation of CD36 and Dgat2, whose protein products mediate fatty acid uptake and triglyceride synthesis, respectively. Taken together, our studies indicate that sepsis leads to a profound change in metabolic gene expression programs and Mkp-1 plays an important role in this process.

Doxycycline hyclate: A schistosomicidal agent in vitro with immunomodulatory potential on granulomatous inflammation in vivo

We investigated the effect in vitro and in vivo of doxycycline hyclate (Dx), a broad-spectrum antibiotic inhibitor of matrix metaloproteinases (MMPs), on adult Schistosoma mansoni worms and granulomatous liver inflammation in infected mice. Adult S. mansoni worms in culture treated with different concentrations of Dx (50–180 μg/mL) were studied for eight days to assess its morphology, eggs production, and mortality. Uninfected mice and those infected with S. mansoni, untreated and treated with praziquantel (Pz; 200 mg/kg) or Dx (50 mg/kg), were evaluated for 60 days. Our results indicated that Dx induced dose-dependent integumentary lesions (bubbles, tubercle collapse, spicule disappearance, peeling, and erosion), reduced mating rate and eggs-laying in adult S. mansoni worms. The effective lethal dose required to kill 50% of worms was 112.0 μg/mL Dx (DL50). In mice, S. mansoni infection induced hepatomegaly, intense IL-4, IL-10, TNF-α and TGF-β production, granulomatous inflammation and hepatic glycogen depletion. The number and size of the granulomas was similar in untreated and Dx-treated animals. Untreated animals showed a predominance of productive granulomas, and intense MMP-2 and MMP-9 activities. Dx-treated mice exhibited a significant increase in IL-4 levels, tissue inflammation, proportion of involutive granulomas, and hepatic collagenogenesis, as well as attenuated MMP-2 and MMP-9 activities. Our findings indicated that Dx is toxic to adult S. mansoni worms in vitro. However, in vitro beneficial effects were not reproduced in vivo, since Dx treatment increased liver granulomatous inflammation and collagenogenesis in S. mansoni-infected mice by a process potentially associated with Dx-mediated hepatic MMP-2 and MMP-9 inhibition.

Adenosine stimulates hepatic glycogenolysis via adrenal glands-liver crosstalk in mice.

Adenosine signaling is involved in glucose metabolism in hepatocytes and myocytes in vitro. However, no information is available regarding the effect of adenosine on glucose metabolism in vivo. Thus, we examined how extracellular adenosine acts on glucose metabolism using mice. Subcutaneous injections of adenosine (10, 25, and 50 mg/kg bodyweight) dose-dependently increased blood glucose levels, with the peak occurring at 30 min post injection. At 30 min after adenosine injection (25 mg/kg bodyweight), glycogen content in the liver, but not the skeletal muscle, was significantly decreased. Hepatic glycogen depletion by fasting for 12 h suppressed the increase of blood glucose levels at 30 min after adenosine injection. These results suggest that adenosine increases blood glucose levels by stimulating hepatic glycogenolysis. To investigate the effect of adenosine on the adrenal gland, we studied the glycogenolysis signal in adrenalectomized (ADX) mice. Adenosine significantly increased the blood glucose levels in sham mice but not in the ADX mice. The decrease in hepatic glycogen content induced by adenosine in the sham mice was partially suppressed in the ADX mice. The level of plasma corticosterone, the main glucocorticoid in mice, was significantly increased in the sham mice by adenosine but its levels were low in ADX mice injected with either PBS or adenosine. These results suggest that adenosine promotes secretion of corticosterone from the adrenal glands, which causes hepatic glycogenolysis and subsequently the elevation of blood glucose levels. Our findings are useful for clarifying the physiological functions of adenosine in glucose metabolism in vivo.

Alcohol-induced ketonemia is associated with lowering of blood glucose, downregulation of gluconeogenic genes, and depletion of hepatic glycogen in type 2 diabetic db/db mice

Alcoholic ketoacidosis and diabetic ketoacidosis are life-threatening complications that share the characteristic features of high anion gap metabolic acidosis. Ketoacidosis is attributed in part to the massive release of ketone bodies (e.g., β-hydroxybutyrate; βOHB) from the liver into the systemic circulation. To date, the impact of ethanol consumption on systemic ketone concentration, glycemic control, and hepatic gluconeogenesis and glycogenesis remains largely unknown, especially in the context of type 2 diabetes. In the present study, ethanol intake (36% ethanol- and 36% fat-derived calories) by type 2 diabetic db/db mice for 9 days resulted in significant decreases in weight gain (∼19.5% ↓) and caloric intake (∼30% ↓). This was accompanied by a transition from macrovesicular-to-microvesicular hepatic steatosis with a modest increase in hepatic TG (∼37% ↑). Importantly, ethanol increased systemic βOHB concentration (∼8-fold ↑) with significant decreases in blood glucose (∼4-fold ↓) and plasma insulin and HOMA-IR index (∼3-fold ↓). In addition, ethanol enhanced hepatic βOHB content (∼5-fold ↑) and hmgcs2 mRNA expression (∼3.7-fold ↑), downregulated key gluconeogenic mRNAs (e.g., Pcx, Pck1, and G6pc), and depleted hepatic glycogen (∼4-fold ↓). Furthermore, ethanol intake led to significant decreases in the mRNA/protein expression and allosteric activation of glycogen synthase (GS) in liver tissues regardless of changes in the phosphorylation of GS, GSK-3β, or Akt. Together, our findings suggest that ethanol-induced ketonemia may occur in concomitance with significant lowering of blood glucose concentration, which may be attributed to suppression of gluconeogenesis in the setting of glycogen depletion in type 2 diabetes.

Inhibition of pyruvate dehydrogenase kinase-4 by l-glutamine protects pregnant rats against fructose-induced obesity and hepatic lipid accumulation

ObjectiveAccumulation of lipids in non-adipose tissues particularly the liver is a feature of tissue insulin resistance. Hepatic glycogen depletion reflects counter glucoregulation in an insulin-resistant state and/or obesity. The effect of l-glutamine on fructose-induced increased hepatic lipid accumulation and depleted glycogen content, particularly in pregnancy, is not known. We therefore aimed at investigating the effect of glutamine on fructose-induced weight gain, hepatic lipids and glycogen contents in pregnant rats and also tested the hypothesis that hepatoprotective role of l-glutamine is through suppression of PDK-4. MethodsEleven-week-old pregnant Wistar rats were allotted into the Control, Glutamine, Fructose and Fructose plus Glutamine groups (6 rats/group). The groups received distilled water (vehicle, p.o.), 1 g/kg bwl-glutamine (p.o.), 10% Fructose (w/v) and 10% Fructose (w/v) plus 1 g/kg bwl-glutamine (p.o.) respectively, daily for 19 days. Biochemical analysis and histology of the liver were performed. ResultsData showed that fructose intake caused insulin resistance, hyperglycemia, hyperlipidemia, increased body weight gain, visceral fat mass, hepatic mass, lactate production, uric acid production, lipid peroxidation and decreased pancreatic β-cell function and hepatic glycogen synthesis. These alterations were accompanied by elevated pyruvate dehydrogenase kinase-4 (PDK-4). However, the fructose-induced dysmetabolism were improved by l-glutamine. ConclusionOur results demonstrate that obesity and hepatic lipid accumulation induced by fructose in pregnant rats is accompanied by increased PDK-4. The findings also suggest that l-glutamine would protect against obesity and hepatic lipid accumulation by suppression of PDK-4.

ANTICOAGULATION INDEPENDENT EFFECTS OF ORAL ANTICOAGULANTS: ON THE SEARCH FOR THE VASCULO-PROTECTIVE EFFECT OF RIVAROXABAN

Because optimising therapy for the management of diabetes mellitus remains challenging, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids (N-3 – eicosapentaenoic acid and docosahexaenoic acid-3:2), compared to metformin, on selected biochemical parameters in male Wistar rats, in an experimental model of diabetes. Forty rats were used for this study. They were divided into eight groups of five rats each, which included: Normal control; Diabetic (D) control; D + N-3; D + low dose Sct (Sct. Lw); D + high dose Sct (Sct. Hi); D + N-3 + Sct.Lw; D + N-3 + Sct.Hi; and D + metformin. Diabetes was induced in overnight fasted rats by the administration of streptozotocin (65 mg/kg b.w., i.p.), 15 min after the administration of nicotinamide (110 mg/kg b.w., i.p.). Nine days later, Sct was administered at 2.5 and 5.0 IU/kg b.w./day (i.m.), while N-3 and metformin were administered at 200 and 180 mg/kg b.w./day (p.o.) respectively, for four weeks. Sct, N-3, and metformin significantly reduced total cholesterol, LDL-C, cortisol, c-telopeptide of type 1 collagen, and collagen type 2 alpha-1. The combined administration of Sct and N-3 had more favorable effects on triglyceride and HDL-C than either monotherapy. Unlike metformin and Sct. Hi, N-3 significantly reduced alkaline phosphatase activity. Moreover, N-3 significantly suppressed the hypocalcaemic, hyperglycaemic, and insulin resistance provoking actions of Sct. Furthermore, N-3 contradicted the hepatic glycogen depletion and inhibition of nitric oxide synthesis brought about by Sct. In conclusion, N-3 demonstrated antagonistic and non-additive actions with Sct. Moreover, the effects of the combined administration of Sct and N-3 were comparable to that of metformin; therefore, they might be considered as therapeutic alternatives in diabetes.

NO SIGNALLING: THE PROCESSES ON THE CONSCIOUS AND UNCONSCIOUS LEVELS

Because optimising therapy for the management of diabetes mellitus remains challenging, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids (N-3 – eicosapentaenoic acid and docosahexaenoic acid-3:2), compared to metformin, on selected biochemical parameters in male Wistar rats, in an experimental model of diabetes. Forty rats were used for this study. They were divided into eight groups of five rats each, which included: Normal control; Diabetic (D) control; D + N-3; D + low dose Sct (Sct. Lw); D + high dose Sct (Sct. Hi); D + N-3 + Sct.Lw; D + N-3 + Sct.Hi; and D + metformin. Diabetes was induced in overnight fasted rats by the administration of streptozotocin (65 mg/kg b.w., i.p.), 15 min after the administration of nicotinamide (110 mg/kg b.w., i.p.). Nine days later, Sct was administered at 2.5 and 5.0 IU/kg b.w./day (i.m.), while N-3 and metformin were administered at 200 and 180 mg/kg b.w./day (p.o.) respectively, for four weeks. Sct, N-3, and metformin significantly reduced total cholesterol, LDL-C, cortisol, c-telopeptide of type 1 collagen, and collagen type 2 alpha-1. The combined administration of Sct and N-3 had more favorable effects on triglyceride and HDL-C than either monotherapy. Unlike metformin and Sct. Hi, N-3 significantly reduced alkaline phosphatase activity. Moreover, N-3 significantly suppressed the hypocalcaemic, hyperglycaemic, and insulin resistance provoking actions of Sct. Furthermore, N-3 contradicted the hepatic glycogen depletion and inhibition of nitric oxide synthesis brought about by Sct. In conclusion, N-3 demonstrated antagonistic and non-additive actions with Sct. Moreover, the effects of the combined administration of Sct and N-3 were comparable to that of metformin; therefore, they might be considered as therapeutic alternatives in diabetes.

PATHOGENIC ROLE OF AUTONOMIC DYSFUNCTION IN COLD INTOLERANCE IN MULTIPLE SCLEROSIS PATIENTS

Because optimising therapy for the management of diabetes mellitus remains challenging, the study investigated the effects of salmon calcitonin (Sct) and/or omega-3 fatty acids (N-3 – eicosapentaenoic acid and docosahexaenoic acid-3:2), compared to metformin, on selected biochemical parameters in male Wistar rats, in an experimental model of diabetes. Forty rats were used for this study. They were divided into eight groups of five rats each, which included: Normal control; Diabetic (D) control; D + N-3; D + low dose Sct (Sct. Lw); D + high dose Sct (Sct. Hi); D + N-3 + Sct.Lw; D + N-3 + Sct.Hi; and D + metformin. Diabetes was induced in overnight fasted rats by the administration of streptozotocin (65 mg/kg b.w., i.p.), 15 min after the administration of nicotinamide (110 mg/kg b.w., i.p.). Nine days later, Sct was administered at 2.5 and 5.0 IU/kg b.w./day (i.m.), while N-3 and metformin were administered at 200 and 180 mg/kg b.w./day (p.o.) respectively, for four weeks. Sct, N-3, and metformin significantly reduced total cholesterol, LDL-C, cortisol, c-telopeptide of type 1 collagen, and collagen type 2 alpha-1. The combined administration of Sct and N-3 had more favorable effects on triglyceride and HDL-C than either monotherapy. Unlike metformin and Sct. Hi, N-3 significantly reduced alkaline phosphatase activity. Moreover, N-3 significantly suppressed the hypocalcaemic, hyperglycaemic, and insulin resistance provoking actions of Sct. Furthermore, N-3 contradicted the hepatic glycogen depletion and inhibition of nitric oxide synthesis brought about by Sct. In conclusion, N-3 demonstrated antagonistic and non-additive actions with Sct. Moreover, the effects of the combined administration of Sct and N-3 were comparable to that of metformin; therefore, they might be considered as therapeutic alternatives in diabetes.

Small molecule inhibition of protein phosphatase 2A in vivo does not disrupt glucose homeostasis in mice.

Identifying new targets for therapeutic intervention that might attenuate cardiovascular complications associated with type 2 diabetes is needed. Earlier we reported that mice treated with a potent and selective small molecule inhibitor (LB1; Lixte Biotechnology Holdings, Inc., East Setauket, NY; 1 mg/kg IP) of protein phosphatase 2A (PP2A) for the last 14 days of an obesogenic diet (12 weeks of fat‐feeding) did not display vascular PP2A hyperactivation, endothelial dysfunction, or hypertension that otherwise developed in fat‐fed mice treated with vehicle (Bharath et al, Diabetes, 2015). We concluded that PP2A hyperactivation should be considered further as a therapeutic target for intervention. Results from another laboratory group indicated that 2 mg/kg LB1 IP (3 hours) evoked hyperglycemia, glucose intolerance, and hepatic glycogen depletion in chow‐fed and fat‐fed (3 days) rats. The authors concluded that targeting PP2A hyperactivation should not be considered as a therapeutic intervention. Based on the incongruent conclusions from the two studies we tested the hypotheses that LB1 treatment for 14‐days impairs: (i) peripheral glucose homeostasis; (ii) hepatic glycogen content; and (iii) insulin‐mediated signal transduction in the liver. To test the first two hypotheses, 7‐week old male C57BL/6J mice consumed standard (Con) or high fat (HF) chow for 12 weeks. Subgroups of Con and HF mice received 1 mg/kg LB1 or saline (Veh) IP for the last 14 days. First, glucose and insulin tolerance testing indicated that LB1 treatment does not impair peripheral glucose homeostasis in Con mice or HF mice. Second, LB1 treatment did not lower hepatic glycogen content, p‐Akt2S474/Akt2, p‐Gsk3ɑS21/Gsk3ɑβ, or p‐GSS641/GS, in lean or obese mice under basal, random‐fed conditions. To test the third hypothesis, age‐matched male mice that consumed standard chow were treated with LB1 or Veh for 14 days. On day 15, after a 6 h fast, insulin or saline was administered (i.v.) to anesthetized mice, and segments of liver were collected to assess p‐Akt2S474/Akt2, p‐GSK3ɑS21/GSK3ɑ, and p‐GSS641/GS. Insulin‐mediated signal transduction in the liver was similar regardless of LB1 treatment. We conclude that LB1 treatment in mice for 14‐days does not impair: (i) peripheral glucose homeostasis; (ii) hepatic glycogen content; or (iii) insulin‐mediated signal transduction in the liver.Support or Funding InformationAmerican Diabetes Association (ADA: 1‐12‐BS‐208, ADA 7‐08‐RA‐164) and National Institutes of Health (NIH: 2R15HL091493) to JDSThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.