incretins and Fatty-Liver

The principle pathological drivers of metabolic dysfunction-associated steatohepatitis (MASH) are obesity and associated insulin resistance, rendering them key therapeutic targets. As glucagon-like peptide 1 receptor agonists (GLP-1RAs) have been licensed for the treatment of diabetes and obesity, they were one of the first drug types to be evaluated in patients with MASH, and successful phase IIa and IIb studies have resulted in progression to phase III clinical trials. Alongside GLP-1RAs, newer combinations with glucagon agonists and/or glucose-dependent insulinotropic peptide (GIP) agonists have been explored in related patient groups, with evidence of improvements in weight, insulin resistance and non-invasive liver parameters. Whether GLP-1RAs have direct, independent effects on MASH or whether they impact on pathophysiology through improvements in weight, insulin resistance and glycaemic control remains a matter of debate. Combinations are being explored, although the potential improvement in efficacy will need to be weighed against the cumulative side-effect burden, potential drug-drug interactions and costs. There is also uncertainty regarding the optimal ratio of glucagon and GIP agonism to GLP-1 agonism in combination agents, and as to whether GIP agonism or antagonism is the optimal approach. Finally, there are also multiple hypothetical permutations combining gut hormone agonists with other emerging assets in the field. Given that the likely dominant mode of action of gut hormone agonists is upstream on weight, initial combinations might focus on agents which have been shown to have a more direct effect on fibrosis, which would include FGF21 and pan-PPAR agonists.

Topics: Animals; Clinical Trials as Topic; Fatty Liver; Fibrosis; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Humans; Incretins; Molecular Targeted Therapy

In the past decade, G protein-coupled receptors have emerged as drug targets, and their physiological and pathological effects have been extensively studied. Among these receptors, GPR119 is expressed in multiple organs, including the liver. It can be activated by a variety of endogenous and exogenous ligands. After GPR119 is activated, the cell secretes a variety of incretins, including glucagon-like peptide-1 and glucagon-like peptide-2, which may attenuate the metabolic dysfunction associated with fatty liver disease, including improving glucose and lipid metabolism, inhibiting inflammation, reducing appetite, and regulating the intestinal microbial system. GPR119 has been a potential therapeutic target for diabetes mellitus type 2 for many years, but its role in metabolic dysfunction associated fatty liver disease deserves further attention. In this review, we discuss relevant research and current progress in the physiology and pharmacology of the GPR119/incretin axis and speculate on the potential therapeutic role of this axis in metabolic dysfunction associated with fatty liver disease, which provides guidance for transforming experimental research into clinical applications.

Topics: Animals; Fatty Liver; Humans; Incretins; Liver Diseases; Molecular Targeted Therapy; Receptors, G-Protein-Coupled

Metabolic disorders are common in patients with chronic hepatitis C virus (HCV) infection. Epidemiologic and clinical data indicate an overprevalence of lipids abnormalite, steatosis, insuline resistance (IR) and diabetes mellitus in HCV patients, suggesting that HCV itself may interact with glucido-lipidic metabolism. HCV interacts with the host lipid metabolism by several mechanisms leading to hepatic steatosis and hypolipidemia which are reversible after viral eradication. Liver and peripheral IR are HCV genotype/viral load dependent and improved after viral eradication. This article examines examine the relationship between HCV, lipid abnormalities, steatosis, IR, and diabetes and the pathogenic mechanisms accounting for these events in HCV-infected patients.

Topics: Animals; Cytokines; Diabetes Mellitus, Type 2; Dyslipidemias; Fatty Liver; Hepacivirus; Hepatitis C, Chronic; Humans; Incretins; Insulin Resistance; Insulin-Secreting Cells; Lipid Metabolism; Mice; Prevalence; Risk Factors; Signal Transduction

Nonalcoholic fatty liver disease (NAFLD) is a serious public health problem. It is now estimated to affect 30% of adults and about 10% of children in the U.S. Hispanics are disproportionably affected with not only higher rates of NAFLD but also more severe disease. Treatment options are currently limited.. In this review, we will focus on a series of novel findings related to the pathobiology of liver damage in nonalcoholic steatohepatitis (NASH) that are attractive targets for development of novel therapeutic strategies for human NASH. In particular, we will discuss four different areas due to their novelty and growing importance including microparticles, the inflammasomes, gut-liver axis and dietary lipids.. There is an urgent need to develop novel safe and effective therapies for the growing NAFLD epidemic. The data discussed in this article provide strong rational to think out of the box when considering novel therapeutic targets for patients with NAFLD.

Topics: Animals; Bile Acids and Salts; Cell-Derived Microparticles; Dietary Fats; Fatty Liver; Humans; Incretins; Inflammasomes; Non-alcoholic Fatty Liver Disease

Dipeptidyl peptidase-4 (DPP-4) is a membrane-associated peptidase, also known as CD26. DPP-4 has widespread organ distribution throughout the body and exerts pleiotropic effects via its peptidase activity. A representative target peptide is glucagon-like peptide-1, and inactivation of glucagon-like peptide-1 results in the development of glucose intolerance/diabetes mellitus and hepatic steatosis. In addition to its peptidase activity, DPP-4 is known to be associated with immune stimulation, binding to and degradation of extracellular matrix, resistance to anti-cancer agents, and lipid accumulation. The liver expresses DPP-4 to a high degree, and recent accumulating data suggest that DPP-4 is involved in the development of various chronic liver diseases such as hepatitis C virus infection, non-alcoholic fatty liver disease, and hepatocellular carcinoma. Furthermore, DPP-4 occurs in hepatic stem cells and plays a crucial role in hepatic regeneration. In this review, we described the tissue distribution and various biological effects of DPP-4. Then, we discussed the impact of DPP-4 in chronic liver disease and the possible therapeutic effects of a DPP-4 inhibitor.

Topics: Carcinoma, Hepatocellular; Dipeptidyl Peptidase 4; End Stage Liver Disease; Extracellular Matrix; Fatty Liver; Gene Expression Regulation, Enzymologic; Hepatitis C; Humans; Incretins; Insulin Resistance; Lipid Metabolism; Liver Neoplasms; Non-alcoholic Fatty Liver Disease

Topics: Diabetes Mellitus, Type 2; Fatty Liver; Humans; Incretins; Liver; Non-alcoholic Fatty Liver Disease

Recent research has led to an interest in the role of the gut and liver in type 2 diabetes mellitus (T2DM).. To review the role of the gastrointestinal system in glucose homoeostasis, with particular focus on the effects of incretin hormones, hepatic steatosis and bile acids.. PubMed and Google Scholar were searched using terms such as incretin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), dipeptidyl peptidase-4 (DPP-4), hepatic steatosis, bile acid and gastric bypass. Additional relevant references were identified by reviewing the reference lists of articles.. Perturbations of incretin hormones and bile acid secretion contribute to the pathogenesis of T2DM, leading to their potential as therapeutic targets. The incretin hormones (GIP and GLP-1) are deactivated by DPP-4. GLP-1 agonists and DPP-4 inhibitors improve glycaemic control in patients with T2DM. Hepatic steatosis, along with insulin resistance, may precede the development of T2DM, and may benefit from anti-diabetes medications. Bile acids play an important role in glucose homoeostasis, with effects mediated via the farnesoid X receptor (FXR) and the cell surface receptor TGR5. The bile acid sequestrant colesevelam has been shown to be effective in improving glycaemic control in patients with T2DM. Altered gastrointestinal anatomy after gastric bypass surgery may also affect enterohepatic recirculation of bile acids and contribute to improved glycaemic control.. Research in recent years has led to new pathways and processes with a role in glucose homoeostasis, and new therapeutic targets and options for type 2 diabetes mellitus.

Topics: Bile Acids and Salts; Blood Glucose; Diabetes Mellitus, Type 2; Fatty Liver; Gastric Bypass; Gastrointestinal Tract; Homeostasis; Humans; Incretins; Non-alcoholic Fatty Liver Disease

Regulatory role of the brain in energy expenditure, appetite, glucose metabolism, and central effects of insulin has been prominently studied. Certain neurons in the hypothalamus increase or decrease appetite via orexigenes and anorexigenes, regulating energy balance and food intake. Hypothalamus is the site of afferent and efferent stimuli between special nuclei and beta- and alpha cells, and it regulates induction/inhibition of glucose output from the liver. Incretines, produced in intestine and in certain brain cells (brain-gut hormones), link to special receptors in the hypothalamus. Central role of insulin has been proved both in animals and in humans. Insulin gets across the blood-brain barrier, links to special hypothalamic receptors, regulating peripheral glucose metabolism. Central glucose sensing, via "glucose-excited" and "glucose-inhibited" cells have outstanding role. Former are active in hyperglycaemia, latter in hypoglycaemia, via influencing beta- and alpha cells, independently of traditional metabolic pathways. Evidence of brain insulin resistance needs centrally acting drugs, paradigm changes in therapy and prevention of metabolic syndrome, diabetes, cardiovascular and oncological diseases.

Topics: Animals; Appetite Depressants; Appetite Regulation; Blood Glucose; Brain; Ceramides; Cognition; Diabetes Mellitus, Type 2; Energy Metabolism; Fatty Liver; Glucagon-Like Peptide 1; Humans; Hypothalamus; Incretins; Insulin; Insulin Resistance; Intracellular Signaling Peptides and Proteins; Metabolic Syndrome; Neuropeptides; Non-alcoholic Fatty Liver Disease; Oligopeptides; Orexins; Pyrrolidonecarboxylic Acid

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic fat accumulation in the absence of significant ethanol consumption, viral infection, or other specific causes of liver disease. Currently the most common chronic liver disease, affecting 30% of the Western world, NAFLD may progress to cirrhosis and end-stage liver disease and may increase the risk of developing diabetes and cardiovascular disease. Although its pathogenesis is unclear, NAFLD is tightly associated with insulin resistance and the metabolic syndrome. No established treatment exists, and current research is targeting new molecular mechanisms that underlie NAFLD and associated cardiometabolic disorders. This review discusses some of these emerging molecular mechanisms and their therapeutic implications for the treatment of NAFLD: microRNAs, incretin analogs/antagonists, liver-specific thyromimetics, AMP-activated protein kinase activators, and nuclear receptors farnesoid X receptor and pregane X receptor.

Topics: AMP-Activated Protein Kinases; Fatty Liver; Gastric Inhibitory Polypeptide; Gastrointestinal Agents; Humans; Incretins; MicroRNAs; Receptors, Cytoplasmic and Nuclear

Type 2 diabetes (T2D) is a risk factor for metabolic dysfunction-associated fatty liver disease (MAFLD), which is becoming the commonest cause of chronic liver disease worldwide. We estimated MAFLD prevalence among patients with T2D using the hepatic steatosis index (HSI) and validated it against liver ultrasound. We also examined whether glucose-lowering medications (GLM) beneficially affected HSI.. We collected data from 46 diabetes clinics (n = 281,381 T2D patients), extracted data to calculate HSI and validated it against ultrasound-detected hepatic steatosis. We then examined changes in HSI among patients with a follow-up visit within 1 year after initiating newer GLMs.. MAFLD (defined by HSI > 36, i.e., a high probability of steatosis) was present in 76.3% of the 78,895 included patients, while only 2.7% had HSI < 30 (low probability of steatosis). After age- and sex-adjusting, higher HSI was associated with higher prevalence of chronic kidney disease (odds ratio 1.35; 95%CI 1.22-1.51) and macroangiopathy (odds ratio 1.18; 95%CI 1.07-1.30). Among 2,179 subjects in the validation cohort, the prevalence of MAFLD was 67.8% and was greater in those with high HSI. Performance of HSI for ultrasound-detected MAFLD was moderate (AUROC 0.70), yet steatosis prevalence was > threefold higher among subjects with HSI > 36 than among those with HSI < 30. Notably, HSI declined significantly ~ 6 months after initiation of dapagliflozin or incretin-based therapies, but not gliclazide.. About three quarters of patients with T2D have HSI values suggestive of MAFLD, a condition associated with macroangiopathy and nephropathy. Treatment with dapagliflozin or incretin therapies might improve MAFLD in T2D.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Diabetes Mellitus, Type 2; Fatty Liver; Female; Follow-Up Studies; Gliclazide; Humans; Hypoglycemic Agents; Incretins; Italy; Male; Middle Aged; Prevalence; Renal Insufficiency, Chronic; Retrospective Studies; Treatment Outcome; Ultrasonography; Young Adult

The gp130 receptor cytokines IL-6 and CNTF improve metabolic homeostasis but have limited therapeutic use for the treatment of type 2 diabetes. Accordingly, we engineered the gp130 ligand IC7Fc, in which one gp130-binding site is removed from IL-6 and replaced with the LIF-receptor-binding site from CNTF, fused with the Fc domain of immunoglobulin G, creating a cytokine with CNTF-like, but IL-6-receptor-dependent, signalling. Here we show that IC7Fc improves glucose tolerance and hyperglycaemia and prevents weight gain and liver steatosis in mice. In addition, IC7Fc either increases, or prevents the loss of, skeletal muscle mass by activation of the transcriptional regulator YAP1. In human-cell-based assays, and in non-human primates, IC7Fc treatment results in no signs of inflammation or immunogenicity. Thus, IC7Fc is a realistic next-generation biological agent for the treatment of type 2 diabetes and muscle atrophy, disorders that are currently pandemic.

Topics: Adaptor Proteins, Signal Transducing; Animals; Binding, Competitive; Cytokine Receptor gp130; Cytokines; Diabetes Mellitus, Type 2; Drug Design; Fatty Liver; Glucose Tolerance Test; Humans; Hyperglycemia; Immunoglobulin G; Incretins; Interleukin-6; Male; Mice; Muscle, Skeletal; Obesity; Pancreas; Phosphoproteins; Protein Engineering; Receptors, Interleukin-6; Recombinant Fusion Proteins; Signal Transduction; Transcription Factors; Weight Gain; YAP-Signaling Proteins

Perturbations in hepatic lipid and very-low-density lipoprotein (VLDL) metabolism are involved in the pathogenesis of obesity and hepatic insulin resistance. The objective of this study is to delineate the mechanism of subdiaphragmatic vagotomy in preventing obesity, hyperlipidemia, and insulin resistance.. By subjecting the complete subdiaphragmatic vagotomized mice to various nutritional conditions and investigating hepatic de novo lipogenesis pathway, we found that complete disruption of subdiaphragmatic vagal signaling resulted in a significant decrease of circulating VLDL-triglyceride compared with the mice obtained sham procedure. Vagotomy further prevented overproduction of VLDL-triglyceride induced by an acute fat load and a high-fat diet-induced obesity, hyperlipidemia, hepatic steatosis, and glucose intolerance. Mechanistic studies revealed that plasma glucagon-like peptide-1 was significantly raised in the vagotomized mice, which was associated with significant reductions in mRNA and protein expression of SREBP-1c (sterol regulatory element-binding protein 1c), SCD-1 (stearoyl-CoA desaturase-1), and FASN (fatty acid synthase), as well as enhanced hepatic insulin sensitivity. In vitro, treating mouse primary hepatocytes with a glucagon-like peptide-1 receptor agonist, exendin-4, for 48 hours inhibited free fatty acid, palmitic acid treatment induced de novo lipid synthesis, and VLDL secretion from hepatocytes.. Elevation of glucagon-like peptide-1 in vagotomized mice may prevent VLDL overproduction and insulin resistance induced by high-fat diet. These novel findings, for the first time, delineate an intrinsic gut-liver regulatory circuit that is mediated by glucagon-like peptide-1 in regulating hepatic energy metabolism.

Topics: Animals; Biomarkers; Blood Glucose; Cells, Cultured; Diet, High-Fat; Disease Models, Animal; Exenatide; Fatty Acid Synthase, Type I; Fatty Liver; Gene Expression Regulation; Glucagon-Like Peptide 1; Hepatocytes; Hyperlipidemias; Incretins; Insulin; Insulin Resistance; Intestinal Mucosa; Intestines; Lipoproteins, VLDL; Liver; Male; Mice, Inbred C57BL; Obesity; Peptides; RNA, Messenger; Signal Transduction; Stearoyl-CoA Desaturase; Sterol Regulatory Element Binding Protein 1; Time Factors; Triglycerides; Up-Regulation; Vagotomy; Vagus Nerve; Venoms

We previously showed that parenteral nutrition (PN) compared with formula feeding results in hepatic insulin resistance and steatosis in neonatal pigs. The current aim was to test whether the route of feeding (intravenous [IV] vs enteral) rather than other feeding modalities (diet, pattern) had contributed to the outcome.. Neonatal pigs were fed enterally or parenterally for 14 days with 1 of 4 feeding modalities as follows: (1) enteral polymeric formula intermittently (FORM), (2) enteral elemental diet (ED) intermittently (IEN), (3) enteral ED continuously (CEN), and (4) parenteral ED continuously (PN). Subgroups of pigs underwent IV glucose tolerance tests (IVGTT) and hyperinsulinemic-euglycemic clamps (CLAMP). Following CLAMP, pigs were euthanized and tissues collected for further analysis.. Insulin secretion during IVGTT was significantly higher and glucose infusion rates during CLAMP were lower in CEN and PN than in FORM and IEN. Endogenous glucose production rate was suppressed to zero in all groups during CLAMP. In the fed state, plasma glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide (GLP)-1, and GLP-2 were different between feeding modalities. Insulin receptor phosphorylation in liver and muscle was decreased in IEN, CEN, and PN compared with FORM. Liver weight was highest in PN. Steatosis and myeloperoxidase (MPO) activity tended to be highest in PN and CEN. Enterally fed groups had higher plasma GLP-2 and jejunum weight compared with PN.. PN and enteral nutrition (EN) when given continuously as an elemental diet reduces insulin sensitivity and the secretion of key gut incretins. The intermittent vs continuous pattern of EN produced the optimal effect on metabolic function.

Topics: Administration, Intravenous; Animals; Animals, Newborn; Blood Glucose; Endpoint Determination; Enteral Nutrition; Fatty Liver; Female; Food, Formulated; Glucagon-Like Peptide 1; Glucagon-Like Peptide 2; Incretins; Inflammation; Insulin; Insulin Resistance; Insulin Secretion; Intestine, Small; Liver; Metabolic Diseases; Nonlinear Dynamics; Organ Size; Parenteral Nutrition; Swine

Given the scarcity of donors, moderately fatty livers (FLs) are currently being considered as possible grafts for orthotopic liver transplantation (OLT), notwithstanding their poor tolerance to conventional cold preservation. The behaviour of parenchymal and sinusoidal liver cells during transplantation is being studied worldwide. Much less attention has been paid to the biliary tree, although this is considered the Achille's heel even of normal liver transplantation. To evaluate the response of the biliary compartment of FLs to the various phases of OLT reliable markers are necessary. Previously we demonstrated that Alkaline Phosphatase was scarcely active in bile canaliculi of FLs and thus ruled it out as a marker. As an alternative, dipeptidylpeptidase-IV (DPP-IV), was investigated. This ecto-peptidase plays an important role in glucose metabolism, rapidly inactivating insulin secreting hormones (incretins) that are important regulators of glucose metabolism. DPP-IV inhibitors are indeed used to treat Type II diabetes. Neuropeptides regulating bile transport and composition are further important substrates of DPP-IV in the enterohepatic axis. DPP-IV activity was investigated with an azo-coupling method in the liver of fatty Zucker rats (fa/fa), using as controls lean Zucker (fa/+) and normal Wistar rats. Protein expression was studied by immunofluorescence with the monoclonal antibody (clone 5E8). In Wistar rat liver, DPP-IV activity and expression were high in the whole biliary tree, and moderate in sinusoid endothelial cells, in agreement with the literature. Main substrates of DPP-IV in hepatocytes and cholangiocytes could be incretins GLP-1 and GIP, and neuropeptides such as vasoactive intestinal peptide (VIP) and substance P, suggesting that these substances are inactivated or modified through the biliary route. In lean Zucker rat liver the enzyme reaction and protein expression patterns were similar to those of Wistar rat. In obese rat liver the patterns of DPP-IV activity and expression in hepatocytes reflected the morphological alterations induced by steatosis as lipid-rich hepatocytes had scarce activity, located either in deformed bile canaliculi or in the sinusoidal and lateral domains of the plasma membrane. These findings suggest that bile canaliculi in steatotic cells have an impaired capacity to inactivate incretins and neuropeptides. Incretin and/or neuropeptide deregulation is indeed thought to play important roles in obesity and insul

Topics: Animals; Dipeptidyl Peptidase 4; Fatty Liver; Fluorescent Antibody Technique; Gene Expression Regulation, Enzymologic; Incretins; Liver; Male; Neuropeptides; Obesity; Rats; Rats, Wistar; Rats, Zucker

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) have been recognized as a metabolic disorder characterized by fatty accumulation of the liver without alcohol consumption. The progression of the diseases has been considered to link to metabolic syndrome, consisting of obesity, diabetes mellitus(DM), dyslipidemia and hypertension. Glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide(GIP) function as incretin and stimulate glucose-mediated insulin production by pancreatic beta cells. Incretin was also reported to have various kinds of extrapancreatic effects including the regulation of hepatic glucose production, the inhibition of pancreatic exocrine secretion, cardioprotective and cardiotropic effects, the regulation of appetite and satiety, and stimulation of afferent sensory nerves. Therefore, incretins are also expected as therapeutic agents for NFLD and NASH.

Topics: Fatty Liver; Glucagon-Like Peptide-1 Receptor; Hepatocytes; Humans; Incretins; Lipid Metabolism; Non-alcoholic Fatty Liver Disease; Receptors, Glucagon