Inhibition Of Gluconeogenesis Research Articles

Glycolysis is reduced in dengue virus 2 infected liver cells

Infections with dengue virus (DENV) remain a worldwide public health problem. A number of bona fide cellular targets of DENV have been identified including liver cells. Despite the many lines of evidence confirming the involvement of hepatocytes during DENV infection, only a few studies have used proteomic analysis to understand the modulation of the cellular proteome occurring upon DENV infection. We utilized a 2D-gel electrophoresis analysis to identify proteins that were differentially regulated by DENV 2 infection of liver (Hep3B) cells at 12 h post infection (hpi) and at 48 hpi. The analysis identifies 4 proteins differentially expressed at 12 hpi, and 14 differentially regulated at 48 hpi. One candidate protein identified as downregulated at 48 hpi in the proteomic analysis (GAPDH) was validated in western blotting in Hep3B cells, and subsequently in induced pluripotent stem cell (iPSC) derived human hepatocytes. The reduced expression of GAPDH was coupled with an increase in NADH, and a significantly reduced NAD + /NADH ratio, strongly suggesting that glycolysis is down regulated in response to DENV 2 infection. Metformin, a well characterized drug used in the treatment of diabetes mellitus, is an inhibitor of hepatic gluconeogenesis was shown to reduce the level of DENV 2 infection and new virus production. Collectively these results show that although glycolysis is reduced, glucose is still required, possibly for use by the pentose phosphate pathway to generate nucleosides required for viral replication.

Tyrosine-phosphorylated DNER sensitizes insulin signaling in hepatic gluconeogenesis by inducing proteasomal degradation of TRB3

ObjectiveHepatic insulin resistance, which leads to increased hepatic gluconeogenesis, is a major contributor to fasting hyperglycemia in type 2 diabetes mellitus (T2DM). However, the mechanism of impaired insulin-dependent suppression of hepatic gluconeogenesis remains elusive. Delta/Notch-like epidermal growth factor (EGF)-related receptor (DNER), firstly described as a neuron-specific Notch ligand, has been recently identified as a susceptibility gene for T2DM through genome-wide association studies. We herein investigated whether DNER regulates hepatic gluconeogenesis and whether this is mediated by enhanced insulin signaling. MethodsThe association between DNER, tribbles homolog 3 (TRB3) and Akt signaling was evaluated in C57BL/6J, ob/ob and db/db mice by western blot analysis. DNER loss-of-function and gain-of-function in hepatic gluconeogenesis were analyzed by western blot analysis, quantitative real-time PCR, glucose uptake and output assay in AML-12 cells and partially validated in primary mouse hepatocytes. Hepatic DNER knockdown mice were generated by tail vein injection of adenovirus to confirm the effects of DNER in vivo. The interaction between DNER and TRB3 was investigated by rescue experiments, cycloheximide chase analysis, co-immunoprecipitation and immunofluorescence. The potential insulin-stimulated phosphorylation sites of DNER were determined by co-immunoprecipitation, LC-MS/MS analysis and site-specific mutagenesis. ResultsHere we show that DNER enhanced hepatic insulin signaling in gluconeogenesis by inhibiting TRB3, an endogenous Akt inhibitor, through the ubiquitin-proteasome degradation pathway. In AML-12 hepatocytes, insulin-stimulated activation of Akt and suppression of gluconeogenesis are attenuated by DNER knockdown, but potentiated by DNER over-expression. In C57BL/6J mice, hepatic DNER knockdown is accompanied by impaired glucose and pyruvate tolerance. Furthermore, the in vitro effects of DNER knockdown or over-expression on both Akt activity and hepatic gluconeogenesis can be rescued by TRB3 knockdown or over-expression, respectively. In response to insulin stimulation, DNER interacted directly with insulin receptor and was phosphorylated at Tyr677. This site-specific phosphorylation is essential for DNER to upregulate Akt activity and then downregulate G6Pase and PEPCK expression, by interacting with TRB3 directly and inducing TRB3 proteasome-dependent degradation. ConclusionsTaken together, the crosstalk between insulin-Akt and DNER-TRB3 pathways represents a previously unrecognized mechanism by which insulin regulates hepatic gluconeogenesis.

GC–MS analysis of 4-hydroxyproline: elevated proline hydroxylation in metformin-associated lactic acidosis and metformin-treated Becker muscular dystrophy patients

Metformin (N,N-dimethylbiguanide), an inhibitor of gluconeogenesis and insulin sensitizer, is widely used for the treatment of type 2 diabetes. In some patients with renal insufficiency, metformin can accumulate and cause lactic acidosis, known as metformin-associated lactic acidosis (MALA, defined as lactate ≥ 5 mM, pH < 7.35, and metformin concentration > 38.7 µM). Here, we report on the post-translational modification (PTM) of proline (Pro) to 4-hydroxyproline (OH-Pro) in metformin-associated lactic acidosis and in metformin-treated patients with Becker muscular dystrophy (BMD). Pro and OH-Pro were measured simultaneously by gas chromatography–mass spectrometry before, during, and after renal replacement therapy in a patient admitted to the intensive care unit (ICU) because of MALA. At admission to the ICU, plasma metformin concentration was 175 µM, with a corresponding lactate concentration of 20 mM and a blood pH of 7.1. Throughout ICU admission, the Pro concentration was lower compared to healthy controls. Renal excretion of OH-Pro was initially high and decreased over time. Moreover, during the first 12 h of ICU admission, OH-Pro seems to be renally secreted while thereafter, it was reabsorbed. Our results suggest that MALA is associated with hyper-hydroxyprolinuria due to elevated PTM of Pro to OH-Pro by prolyl-hydroxylase and/or inhibition of OH-Pro metabolism in the kidneys. In BMD patients, metformin, at the therapeutic dose of 3 × 500 mg per day for 6 weeks, increased the urinary excretion of OH-Pro suggesting elevation of Pro hydroxylation to OH-Pro. Our study suggests that metformin induces specifically the expression/activity of prolyl-hydroxylase in metformin intoxication and BMD.

Novel phloretin-based combinations targeting glucose metabolism in hepatocellular carcinoma through GLUT2/PEPCK axis of action: in silico molecular modelling and in vivo studies.

Hepatocellular carcinoma (HCC) is commonly associated with disturbances in glucose metabolism and enhanced glycolysis. However, a controversial role for gluconeogenesis was reported to be tumor-promoting and tumor-suppressive. We investigated novel anti-HCC treatments through either the simultaneous inhibition of glycolysis and gluconeogenesis by "phloretin" and "sodium meta-arsenite", respectively (Combination 1); or the concurrent inhibition of glycolysis and induction of gluconeogenesis by phloretin and dexamethasone, respectively, (combination 2). A total of 110 Swiss albino mice were divided into eleven groups, HCC was induced by N, N-dimethyl-4-aminoazobenzene. We have measured the expression of the glucose transporter 2 (GLUT2), Phosphoenolpyruvate carboxykinases (PEPCK), Caspase-3, Beclin 1, Cyclin D1, and cytokeratin 18 genes; blood glucose and ATP levels; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. Furthermore, in silico molecular docking was performed to investigate the potential drug-receptor interactions. Histologically, the phloretin-based combinations resulted in a significant regression of malignant tissue compared to various treatments. GLUT2 and PEPCK mRNA analysis indicated successful off/on modulation of glycolysis and gluconeogenesis. Docking confirmed the potent binding between phloretin, sodium meta-arsenite, and dexamethasone with GLUT2, PEPCK, and Retinoid X Receptor Alpha, respectively. Molecularly, Combination 2 resulted in the highest reduction in cyclin D1, cytokeratin 18, and Beclin 1 expression contemporaneously with the upregulation in Caspase-3 levels. Biochemically, both combinations caused a significant reduction in ATP levels, ALT, and AST activity compared to the other groups. In conclusion, we propose two novel phloretin-based combinations that can be used in treating HCC through the regulation of glucose metabolism and ATP production.

Effect of cooking and storage temperature on resistant starch in commonly consumed Indian wheat products and its effect upon blood glucose level

Background/objectivesThe health benefits provided by resistant starch have been well documented; however, few studies are available on the resistant starch content of wheat products in India. Moreover, few studies have examined the in vivo efficacy of resistant starch in wheat products in improving glucose levels. This study was conducted to evaluate the effect of cooking and storage temperature on the formation of resistant starch in Indian wheat products and its effect on blood glucose levels in humans and rats.MethodsWheat products were prepared by common cooking methods including roasting (Chapati), boiling (Dalia), Shallow frying (Paratha), and Deep frying (Poori). They were then stored at different temperatures including freshly prepared within 1 h (T1), stored for 24 h at room temperature (20-22°C) (T2), kept at 4°C for 24 h (T3) and reheated after storing at 4°C for 24 h (T4). The products were then analyzed for proximate composition (moisture, crude protein, crude fat, ash crude fibre, and carbohydrates). The effect of different cooking methods and storage temperatures on Resistant, non-resistant and total starch, total dietary fibre (soluble and insoluble), in vitro starch digestion rate (rapidly and slowly digestible starch), amylose and amylopectin content were analysed using standard operating procedures. The effect of products found to have higher resistant starch was studied on the post prandial blood glucose response of 10 healthy individuals using change in by analysing their glycemic index and glycemic load of wheat products. Further, the effect of resistant starch rich chapati on the blood glucose level of rats was also studied. Tukey’s test in factorial CRD was used to assess the effect of cooking and temperature on various parameters.ResultsThe amount of resistant starch was found to be high in dalia (boiling, 7.74%), followed by parantha (shallow frying, 4.94%), chapati (roasting, 2.77%) and poori (deep frying 2.47%). Under different storage temperatures, it was found high in products stored at 4°C (T3), followed by products stored at room temperature (T2), reheated products (T4) and lesser in freshly prepared products (T1). The glycemic index and glycemic load were found low in chapati (43, 32.3) and dalia (41.1, 28.6) stored at 4°C (T3) compared to others. The resistant starch content found in chapati stored at T3 was found to be more effective at reducing blood glucose levels in rats from 291.0 mg/100 mL to 225.2 mg/100 mL in 28 days of study compared to freshly prepared chapati (T1) and stored at room temperature (T2).ConclusionCooking methods including boiling, roasting and shallow frying increased the amount of resistant starch in foods, but cooking methods such as deep frying decreased the amount of resistant starch in food. Products stored at 4°C and at room temperature for 24 h increased the amount of resistant starch whereas the products that were freshly cooked and reheated decreased the amount of resistant starch in foods. At 4°C the stored products have a high amount of insoluble dietary fibre, slowly digestible starch, high amylose and low glycemic index. They take time to digest, meaning that they slowly increase blood glucose levels. The effect of insoluble dietary fibre and resistant starch in the inhibition of glucose diffusion in the small intestine is suggested to be due to the absorption or inclusion of the smaller sugar molecules. In vivo research showed that fibre and resistant starch in the digestive system of rats acts as the main factors in slowing glucose absorption and reducing a rise in blood glucose levels by promoting glycogen synthesis and inhibition of gluconeogenesis.

The anti-diabetic effects of metformin are mediated by regulating long non-coding RNA.

Type 2 diabetes (T2D) is a metabolic disease with complex etiology and mechanisms. Long non-coding ribonucleic acid (LncRNA) is a novel class of functional long RNA molecules that regulate multiple biological functions through various mechanisms. Studies in the past decade have shown that lncRNAs may play an important role in regulating insulin resistance and the progression of T2D. As a widely used biguanide drug, metformin has been used for glucose lowering effects in clinical practice for more than 60years. For diabetic therapy, metformin reduces glucose absorption from the intestines, lowers hepatic gluconeogenesis, reduces inflammation, and improves insulin sensitivity. However, despite being widely used as the first-line oral antidiabetic drug, its mechanism of action remains largely elusive. Currently, an increasing number of studies have demonstrated that the anti-diabetic effects of metformin were mediated by the regulation of lncRNAs. Metformin-regulated lncRNAs have been shown to participate in the inhibition of gluconeogenesis, regulation of lipid metabolism, and be anti-inflammatory. Thus, this review focuses on the mechanisms of action of metformin in regulating lncRNAs in diabetes, including pathways altered by metformin via targeting lncRNAs, and the potential targets of metformin through modulation of lncRNAs. Knowledge of the mechanisms of lncRNA modulation by metformin in diabetes will aid the development of new therapeutic drugs for T2D in the future.

An In Vitro Pharmacognostical Study on Gluconeogenesis and Glucose

Traditional medicine over 60% of the world’s population used for health care name as Mukia maderaspatana (L.) M. Roem. (Cucurbitaceae) (Mukia) is extensively important medicine as an anti-inflammatory plant. It is rich in content of phenolics that exerts various medicinal properties. Mukia extract and its derivatives phenolics such as quercetin and phloroglucinol are investigated for their in vitro anti-inflammatory activity. Materials used was Quercetin, phloroglucinol, and methanol which extract of the dried whole plant (0.55 and 0.6 mg/ml) were studied for the inhibition of gluconeogenesis and glucose Phenolics of Mukia were analyzed by HPLC and UV-spectroscopy. Results obtained were Glucose (1.5 mg/g/h) was synthesized from pyruvate, the synthesis was whole inhibited by insulin (1 U/ml). Quercetin at 0.35 and 0.6 mg/ml caused 60% and 90% inhibition (0.43 mg/g/h and 0.12 mg/g/h glucose). Addition of insulin did not increase inhibition. Phloroglucinol inhibited 100% glucose production with or without insulin. Mukia (0.20 mg/ml) inhibited gluconeogenesis (0.65 mg/g/h) by 40%, and with insulin, inhibition increased to 50% (0.59 mg/g/h). At 0.6 mg/ml, glucose synthesis was stimulated by1.3-fold, but with insulin gets inhibited by 90% (0.12 mg/g/h glucose). Mukia possessed no effect on glucose uptake, in case it potentiated the activity of insulin mediated glucose uptake (153.82 ± 12.30 mg/dl/g/30 min) compared with insulin control (122.41 ± 9.14 mg/dl/g/30 min) (p &lt; 0.02). HPLC analysis revealed the presence of phenolics. Results were concluded scientific rationale for the use of Mukia in medicine as an anti-inflammatory nutraceutical.

SCH772984 ameliorates lipopolysaccharide-induced hypoglycemia in mice through reversing MEK/ERK/Foxo1-mediated gluconeogenesis suppression.

Lipopolysaccharide (LPS) results in a lethal hypoglycemic response. However, the main molecular mechanism involved in LPS-induced glucose metabolism disorder is poorly understood. This study intends to investigate the signaling pathways involved in LPS-induced hypoglycemia and potential efficacy of extracellular signal-regulated kinase (ERK) inhibitor SCH772984. The effects of LPS and SCH772984 on gluconeogenesis, glucose absorption, and glycogenolysis were evaluated by pyruvate tolerance test, oral glucose tolerance test, and glucagon test, respectively. After a single intraperitoneal injection of 0.5mg/kg LPS, the mice's blood glucose levels and gluconeogenesis ability were significantly lower than that of control group. Besides, mRNA and protein expression of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) decreased significantly after LPS treatment. LPS induced the phosphorylation of ERK1/2, MEK1/2 (mitogen-activated protein kinase), and Foxo1 while inhibited Foxo1 expression in the nucleus, indicating an important role of the MEK/ERK/Foxo1 signaling in the inhibition of gluconeogenesis by LPS. Furthermore, SCH772984 elevated blood glucose, increased the G6Pase and PEPCK expression, and inhibited pERK1/2 and pFoxo1 expression in LPS-induced mice. In summary, LPS inhibited gluconeogenesis and induced hypoglycemia through the MEK/ERK/Foxo1 signal pathway, and ERK inhibitor could effectively reverse decreased blood glucose in mice with LPS treatment. These findings provide a novel therapeutic target for LPS-induced hypoglycemia.

Acute Endoplasmic Reticulum Stress Suppresses Hepatic Gluconeogenesis by Stimulating MAPK Phosphatase 3 Degradation.

Drug-induced liver injury (DILI) is a widespread and harmful disease, and is closely linked to acute endoplasmic reticulum (ER) stress. Previous reports have shown that acute ER stress can suppress hepatic gluconeogenesis and even leads to hypoglycemia. However, the mechanism is still unclear. MAPK phosphatase 3 (MKP-3) is a positive regulator for gluconeogenesis. Thus, this study was conducted to investigate the role of MKP-3 in the suppression of gluconeogenesis by acute ER stress, as well as the regulatory role of acute ER stress on the expression of MKP-3. Results showed that acute ER stress induced by tunicamycin significantly suppressed gluconeogenesis in both hepatocytes and mouse liver, reduced glucose production level in hepatocytes, and decreased fasting blood glucose level in mice. Additionally, the protein level of MKP-3 was reduced by acute ER stress in both hepatocytes and mouse liver. Mkp-3 deficiency eliminated the inhibitory effect of acute ER stress on gluconeogenesis in hepatocytes. Moreover, the reduction effect of acute ER stress on blood glucose level and hepatic glucose 6-phosphatase (G6pc) expression was not observed in the liver-specific Mkp-3 knockout mice. Furthermore, activation of protein kinase R-like ER kinase (PERK) decreased the MKP-3 protein level, while inactivation of PERK abolished the reduction effect of acute ER stress on the MKP-3 protein level in hepatocytes. Taken together, our study suggested that acute ER stress could suppress hepatic gluconeogenesis by stimulating MKP-3 degradation via PERK, at least partially. Thus, MKP-3 might be a therapeutic target for DILI-related hypoglycemia.

Insulin resistance and iatrogenic hyperinsulinemia in type 1 diabetes - norm or complication? Role of metformin in type 1 diabetes mellitus

There is a rising trend of overweight and obesity among individuals with type 1 diabetes. This is often associated with decreased insulin sensitivity, increased insulin dose requirements and poor glycemic control. Insulin resistance is a state of diminished effect of insulin on target tissues, despite normal or elevated serum insulin levels. Metformin as an adjunct to insulin in treating overweight or also not specific image of insulin resistance (without overweight or hormonal disorders) adults with type 1 diabetes is increasingly used. The main goal of this off-label type 1 diabetes treatment method is to improve insulin signaling leading to a subsequent increase in glucose uptake by skeletal myocytes, inhibition of hepatic gluconeogenesis and, as a result, a reduction in the need for a daily dose of insulin. The use of metformin as an addition to insulin may increase the chance of achieving target glucose control and reduce the anabolic effect of this hormone. Metformin can improve insulin sensitivity, glycemia and modulate cardiovascular disease risk factors or nonalcoholic fatty liver disease. In the vast majority of clinical trials conducted with metformin in type 1 diabetes, the effect of the drug on daily insulin doses, improvement in lipid parameters, and decline in body fat was assessed without correlating pre-specified outcomes with drug plasma concentrations.

Enhanced glucose homeostasis via Clostridium symbiosum-mediated glucagon-like peptide 1 inhibition of hepatic gluconeogenesis in mid-intestinal bypass surgery.

The small intestine is known to play a crucial role in the development and remission of diabetes mellitus (DM). However, the exact mechanism by which mid-small intestinal bypass improves glucose metabolism in diabetic rats is not fully understood. To elucidate the mechanisms by which mid-small intestinal bypass improves glucose metabolism. Streptozotocin (STZ) was used to induce DM in Sprague-Dawley (SD) rats at a dose of 60 mg/kg. The rats were then randomly divided into two groups: The mid-small intestine bypass (MSIB) group and the sham group (underwent switch laparotomy). Following a 6-wk recovery period post-surgery, the rats underwent various assessments, including metabolic parameter testing, analysis of liver glycogen levels, measurement of key gluconeogenic enzyme activity, characterization of the gut microbiota composition, evaluation of hormone levels, determination of bile acid concentrations, and assessment of the expression of the intestinal receptors Takeda G protein-coupled receptor 5 and farnesoid X receptor. The MSIB group of rats demonstrated improved glucose metabolism and lipid metabolism, along with increased hepatic glycogen content. Furthermore, there was a decrease in the expression of the key gluconeogenic enzymes phosphoenolpyruvate carboxykinase 1 and glucose-6-phosphatase. Importantly, the MSIB group exhibited a substantial increase in the abundances of intestinal Lactobacillus, Clostridium symbiosum, Ruminococcus gnavus, and Bilophila. Moreover, higher levels of secondary bile acids, such as intestinal lithocholic acid, were observed in this group. Remarkably, the changes in the gut microbiota showed a significant correlation with the expression of key gluconeogenic enzymes and glucagon-like peptide 1 (GLP-1) at 6 wk postoperatively, highlighting their potential role in glucose regulation. These findings highlight the beneficial effects of mid-small intestine bypass on glucose metabolism and the associated modulation of the gut microbiota. The findings of this study demonstrate that the introduction of postoperative intestinal Clostridium symbiosum in the mid-small intestine contributes to the enhancement of glucose metabolism in nonobese diabetic rats. This improvement is attributed to the increased inhibition of hepatic gluconeogenesis mediated by GLP-1, resulting in a favorable modulation of glucose homeostasis.

THU382 It’s Not What It Seems - Metformin Induced Severe Lactic Acidosis Mimicking Euglycemic Diabetic Ketoacidosis

Abstract Disclosure: M. Shaukat: None. R. Memon: None. M. Mack: None. E. Galarza: None. R. Saeed: None. Diabetic Ketoacidosis (DKA) is a life-threatening complication and, occasionally, the initial presentation of Diabetes Mellitus (DM). DKA can rarely present without elevated blood glucose levels, known as Euglycemic DKA, now typically associated with SGLT-2 inhibitors. Metformin is known to cause lactic acidosis but has not been reliably associated with euglycemic DKA. We present a case of metformin-associated lactic acidosis with renal failure and ketosis mimicking euglycemic DKA. Case: 82-year-old female with a history of DM type 2 on metformin and hypertension presented to the Emergency Department (ED) with complaints of presyncope, vomiting and generalized weakness for two weeks. In the ED, her temp. was 90.3 F and BP was 66/28 mmHg. Her labs revealed a potassium of 5.4mmol/L, bicarbonate 5 mmol/L, Creatinine 3.68 mg/dL (baseline 0.7mg/dL), Anion gap (AG) 45mmol/L, Lactate 25.1 mmol/L and Beta-hydroxybutyrate of 21.4 mg/dL. CT Scan of the chest and abdomen showed a 2 cm liver mass and pancreatitis. She was taken to the ICU and started on antibiotics, IV fluids, and vasopressors. The following day, her lactate was 13.5mg/dL, AG was 37mmol/L and Beta-hydroxybutyrate increased to 53.5mg/dL. Her blood sugars remained between 140-180mg/dL and her hemoglobin A1c was in the prediabetic range at 6.1%. She was thought to be in metformin induced euglycemic diabetic ketoacidosis and was started on an insulin drip with 5% Dextrose and 0.45% Normal Saline. Nephrology was consulted and she underwent hemodialysis for metformin toxicity. She remained on the insulin drip for 48 hours after which she was successfully weaned off. She currently remains off on any antidiabetic medication and is doing well. Discussion: DKA is a life-threatening complication of DM that presents as hyperglycemia, ketonemia, and AGMA. Euglycemic DKA is distinguished by blood glucose levels less than 250mg/dL and is usually seen with pregnancy, fasting states and use of SGLT-2 inhibitors. Previous cases of metformin-associated lactic acidosis (MALA) and concurrent euglycemic DKA have been reported, out of which several patients were concurrently on SGLT-2 inhibitors. After a thorough literature review, we were unable to determine a causal mechanism linking metformin and euglycemic DKA. In the reported cases, we believe that renal failure from various causes precipitated MALA due to decrease metformin clearance, with ketosis caused by starvation and exacerbated by metformin-induced inhibition of hepatic gluconeogenesis, further aggravated by an increase in stress hormones resulting in increased insulin resistance and ultimately leading to the development of the severe ketoacidosis. Even though this phenomenon has previously been referred to as “Metformin-induced euglycemic DKA”, we believe that this is more akin to a mimic, rather than true DKA. Presentation: Thursday, June 15, 2023

Unusual case of concurrent metformin-associated lactic acidosis and euglycaemic ketoacidosis

Metformin-associated lactic acidosis (MALA) and euglycaemic diabetic ketoacidosis (EKA) are both life-threatening endocrine emergencies. MALA is a well-documented complication of anti-glycaemic therapy in diabetics while EKA is an increasingly recognized disease entity with the advent of use of sodium-glucose co-transporter-2 (SGLT-2) inhibitors. However, the occurrence of concurrent metformin-associated lactic acidosis and euglycaemic ketoacidosis (MALKA) is uncommon and rarely reported in the literature. We report an unusual case of MALKA, in a 74-year-old gentleman with no previous history of chronic kidney disease and SGLT-2 inhibitor use, who presented with altered mental status, acute renal failure and profound high anion-gap metabolic acidosis (HAGMA) with lactaemia, ketonaemia and normoglycaemia (pH 6.965, bicarbonate 3.1, creatinine 522, glucose 6.6, lactate 17.5, ketones &gt;8). The patient was initiated on intravenous insulin infusion with dextrose-containing drip and continuous renal replacement therapy (CRRT) in the intensive care unit (ICU). The patient had a prolonged hospital stay but was eventually discharged with a normalised renal function without need for long-term dialysis. The parallel occurrence of MALA and EKA suggest a metformin-associated inhibition of gluconeogenesis. This case highlights the importance of early recognition and investigation of concurrent diabetic ketoacidosis in the presence of MALA and vice versa as MALKA benefits from both prompt institution of parenteral glucose therapy and insulin infusion and consideration of initiation of haemodialysis.

The mechanism of action of Spirulina as antidiabetic: a narrative review

Spirulina happens to be a special type of blue-green algae that originally emerged 3.5 billion years ago and was used as a source of nutrition. Spirulina gets its name from the filaments’ spiral or helical structure, but its true name is taxonomically Genus Arthrospira which encompasses several species. The most common species are S. fusiformis, S. maxima, and S. platensis. It is rich in various nutrients and chemical components including protein, carbohydrates, lipids, vitamins, minerals, pigments, chlorophyll, and enzymes. Spirulina’s active molecules and rich nutrients make it have several pharmacological activities and uses including antioxidant, anti-inflammatory, immunomodulatory, immune system booster, anticancer, antiviral activity, and neuroprotective properties. It is also utilized as a nutritional supplement and for weight loss. Moreover, several studies confirm that Spirulina improves insulin sensitivity and reduces blood glucose levels in rat models as well as diabetic patients. The reason behind this unique behavior could be credited to the presence of several active components in it, but the action’s fundamental mechanism is still a matter of debate. Several studies have suggested different mechanisms including anti-inflammatory activity, increased insulin sensitivity, inhibition of gluconeogenesis, antioxidant activity, modulating gut microbiota composition, improved glucose homeostasis, and insulin receptor activation. Therefore, it became clear that Spirulina is a mine of active substances used as a nutritional supplement and reduces blood glucose levels or used in conjunction with other treatments to tackle type 2 diabetes. Further exploration is required to fully explain its effects on human physiology and determine optimal dosages for treatment.

Lactate signaling and fuel selection in rainbow trout: mobilization of energy reserves.

Lactate is now recognized as a regulator of fuel selection in mammals because it inhibits lipolysis by binding to the hydroxycarboxylic acid receptor 1 (HCAR1). The goals of this study were to quantify the effects of exogenous lactate on: 1) lipolytic rate or rate of appearance of glycerol in the circulation (Ra glycerol) and hepatic glucose production (Ra glucose), and 2) key tissue proteins involved in lactate signaling, glucose transport, glycolysis, gluconeogenesis, lipolysis, and β-oxidation in rainbow trout. Measurements of fuel mobilization kinetics show that lactate does not affect lipolysis as it does in mammals (Ra glycerol remains at 7.3 ± 0.5 µmol·kg-1·min-1), but strongly reduces hepatic glucose production (16.4 ± 2.0 to 8.9 ± 1.2 µmol·kg-1·min-1). This reduction is likely induced by decreasing gluconeogenic flux through the inhibition of cytosolic phosphoenolpyruvate carboxykinase (Pck1, alternatively called Pepck1; 60% and 24% declines in gene expression and protein level, respectively). It is also caused by lactate substituting for glucose as a fuel in all tissues except white muscle that increases glut4a expression and has limited capacity for monocarboxylate transporter (Mct)-mediated lactate import. We conclude that lipolysis is not affected by hyperlactatemia because trout show no activation of autocrine Hcar1 signaling (gene expression of the receptor is unchanged or even repressed in red muscle). Lactate regulates fuel mobilization via Pck1-mediated suppression of gluconeogenesis and by replacing glucose as a fuel. This study highlights important functional differences in the Hcar1 signaling system between fish and mammals for the regulation of fuel selection.

Metformin and its redox-related mechanisms of action in type 2 diabetes

Type 2 diabetes (T2D) is a long-term metabolic disease characterized by progressive β-cell functional decline and insulin resistance, which increases the risk of cardiovascular complications as well as associated-morbidity and mortality. Evidence suggests a strong relationship between hyperglycaemia, oxidative stress and the development and progression of T2D. Indeed, a hyperglycaemic state can reduce the activity of antioxidant enzymes and increase lipid peroxidation and protein oxidation products, as well as DNA damage. At present, metformin is the recommended first-line glucose-lowering agent in patients with T2D. Despite the vast clinical experience gained over several decades of use, several mechanisms of action of metformin have yet to be fully elucidated. This review provides an overview of the existing literature concerning the complicated interplay between oxidative stress and T2D and the molecular mechanisms underlying the redox-related mechanisms of action of metformin, which include (but are not limited to) interaction with AMP-activated protein kinase (AMPK)-dependent and AMPK-independent mechanisms, inhibition of gluconeogenesis and action on leukocyte–endothelium interactions.

Fucus vesiculosus polysaccharide alleviates type 2 diabetes in rats via remodeling gut microbiota and regulating glycolipid metabolism-related gene expression

The antidiabetic activity and underlying mechanisms of Fucus vesiculosus polysaccharide (FVP) were studied in type 2 diabetic rats. Our results exhibited that FVP intervention reversed body weight loss, alleviated hyperglycemia and insulin resistance in diabetic rats. FVP also had the potential to ameliorate dyslipidemia, liver and kidney dysfunction, decrease oxidative stress, promote glycogen synthesis, and boost short-chain fatty acid production and total bile acid excretion. 16S rRNA gene sequencing analysis suggested that FVP interfered with the gut microbiota in a beneficial manner. Moreover, RT-qPCR results demonstrated that the antidiabetic activity of FVP in connection with the acceleration of blood glucose absorption and glycogen synthesis, the inhibition of gluconeogenesis, and the regulation of lipid metabolism in the liver. These findings suggested that FVP had antidiabetic effects on high-fat diet and STZ-induced diabetic rats and could be a potential resource for treating type 2 diabetes mellitus.

Effects of transportation on physiological indices and metabolomics of the large yellow croaker Larimichthys crocea.

The aim of this study was to investigate the survival rate, biochemical indices, and metabolome changes of the large yellow croaker after 48 h of live transportation. Two hundred and forty large yellow croakers (body weight: 23.4 ± 5.3 g, total length: 12.2 ± 0.7 cm) were used in this experiment. The transport buckets were filled with fresh seawater and the parameters of the water were a temperature of 16 ± 0.5 °C and a dissolved oxygen content of 6.0-7.2 mg/L. Large yellow crokers were first divided to 0, 10, 20, and 30 mg/L MS-222 groups to observe the 12 h survival rate. The survival rate of 10 mg/L MS-222 group (T1) was the 95%, highest of all, and was further analyzed. The results of liver biochemical indices indicated inhibition of gluconeogenesis and pentose phosphate pathway metabolism. In addition, metabolomics analysis identified significantly differentially expressed metabolites between T1 group and 0 mg/L MS-222 control (C) groups. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) results revealed that the pathways of amino acid metabolism, especially the lysine, aspartate, and homoserine in the liver were significantly affected. In conclusion, the combination of metabolomics and liver biochemical assays provided a characterization of the response mechanism of L. crocea exposed to live transportation.

222-OR: Metformin Reduces Fasting Glycemia in Well-Controlled Type 2 Diabetes by Promoting Aerobic Glycolysis Independent of Decreasing Endogenous Glucose Production

It is well established that metformin improves glycemic control in individuals with poorly-controlled type 2 diabetes (T2D) by reducing rates of endogenous glucose production (EGP) mediated by inhibition of hepatic gluconeogenesis. However, the mechanism by which metformin reduces blood glucose levels in well-controlled individuals with T2D is still unknown. To address this question, we examined rates of EGP, lactate turnover and hepatic triglyceride (TAG), ATP and glycogen content in near-normoglycemic individuals with T2D (n=10, HbA1c 7±1%) with (M+; 1000 mg bid x 2 wks) and without (M-; 2 wks) metformin treatment using the PINTA method with [2H7]glucose and [3-13C]lactate tracer infusions in combination with 1H- /31P- /13C- magnetic resonance spectroscopy. Metformin treatment did not affect rates of EGP, but reduced fasting plasma glucose concentrations by 30% (p&amp;lt;0.01 vs. M-), which could be attributed to increased rates of glucose clearance (+18%, p&amp;lt;0.005 vs. M-) resulting in increased lactate production (+14%, p&amp;lt;0.01 vs. M-). These changes were associated with decreased hepatic ATP content (-20%, p&amp;lt;0.05 vs. M-), increased hepatic glycogen content (+40%, p&amp;lt;0.05 vs. M-) and no changes in hepatic TAG content. Conclusion: In contrast to the glucose-lowering effect of metformin in poorly-controlled T2D, which is due to reductions in gluconeogenesis, this study demonstrates that in well-controlled T2D metformin reduces fasting glycemia - independent of reductions in EGP - primarily by increasing rates of aerobic glycolysis as reflected by increased peripheral glucose clearance and lactate production as well as reduced hepatic ATP content, which is consistent with metformin-induced inhibition of mitochondrial electron transport chain activity. Disclosure T.Sarabhai: None. T.E.Lamoia: None. S.Friesl: None. M.Jonuscheit: None. K.Petersen: Advisory Panel; Novo Nordisk, Research Support; Merck Sharp &amp; Dohme Corp., Gilead Sciences, Inc. G.I.Shulman: Consultant; Novo Nordisk, DiCerna Pharmaceuticals, Inc., Bayer Consumer Care AG, Kriya Therapeutics, Arrowhead Pharmaceuticals, Inc., ESPERION Therapeutics, Inc., Other Relationship; AstraZeneca, Merck &amp; Co., Inc., Janssen Research &amp; Development, LLC, iMetabolic Biopharma Corporation, Maze Therapeutics, 89bio, Inc., Equator Therapeutics, Inc., Generian Pharmaceuticals, Fortress Biotech, Inc., OrsoBio, Aro Biotherapeutics Company, Stock/Shareholder; Levels Health, Inc. M.Roden: Advisory Panel; Eli Lilly and Company, Consultant; TARGET PharmaSolutions, Inc., Research Support; Boehringer-Ingelheim, Novo Nordisk, Novartis, Sanofi.

289-OR: Defining Pathway-Selective Insulin Resistance in Type 2 Diabetes Using iPS Cell-Derived Hepatocytes

Hepatic insulin resistance is central to type 2 diabetes (T2D), fatty liver disease, and metabolic syndrome. To identify the fundamental, cell-autonomous defects underlying hepatic insulin resistance in T2D, we have used inducible human pluripotent stem (iPS) cells derived from 16 individuals with and without T2D differentiated to hepatocytes (iHeps) and studied in vitro. Consistent with pathway selective insulin resistance, we find that insulin failed to suppress gene expression of critical gluconeogenic enzymes (PCK1, G6PC) but continued to stimulate increased expression of the lipogenic enzymes, fatty acid synthase and acetyl Co-A carboxylase 1 in T2D iHeps. iHeps from T2D also displayed reduced insulin receptor tyrosine phosphorylation and reduced phosphorylation through the IRS/Akt pathway. Global phosphoproteomics in control and T2D iHeps identified 378 unique phosphosites regulated by insulin, and many dysregulated phosphosites within the classical insulin signaling pathway (IRS, AKT1/2, GSK3, FOXO1, RPS6KB1, TSC2) and components of gene transcription regulation, membrane trafficking, Rho-GTPases, vesicle transport. Using a kinome-wide data set created with synthetic peptide libraries to profile almost all functional known human serine/threonine kinases, we found the alterations in insulin signaling mapped to AKT, P70S6K, P90S6K, RSK, PKCτ, and SGK kinases. Thus, iHeps from T2D patients show pathway-selective insulin resistance with a loss of suppression of gluconeogenesis by insulin yet persistent activation of lipogenesis, even in vitro, in the absence of any circulating factor exposure. T2D iHeps also show a dysregulated phosphorylation network that provides new clues to the kinases whose action is altered in T2D and hepatic insulin resistance. Disclosure A.Gattu: None. A.Krook: None. J.R.Zierath: None. M.Mann: None. C.Kahn: None. Funding National Institutes of Health (T32DK007260-46)