exenatide and Fibrosis

To assess the efficacy of exenatide (EXE) once weekly + dapagliflozin once daily (DAPA) versus each drug alone in reducing biomarkers of fatty liver/steatosis and fibrosis in a post hoc analysis of DURATION-8, a 104-week study in 695 patients with type 2 diabetes uncontrolled by metformin monotherapy.. We evaluated the impact of the study treatments on non-invasive markers of hepatic steatosis (fatty liver index [FLI] and non-alcoholic fatty liver disease [NAFLD] liver fat score), fibrosis (fibrosis-4 index [FIB-4]) and severe fibrosis (NAFLD fibrosis score), along with liver enzymes and insulin resistance, at weeks 28 and 52. All outcomes in this analysis were exploratory, with nominal P values reported.. At week 28, biomarkers of fatty liver/steatosis and fibrosis were reduced from baseline in all treatment groups. At week 28, EXE once weekly + DAPA effects for decrease in FLI were stronger than those of EXE once weekly + placebo (PLB; -2.92, 95% confidence interval [CI] -5.11, -0.73; P = 0.0092) or DAPA+PLB (-2.77 [95% CI -4.93, -0.62]; P = 0.0119), and stronger than those of EXE once weekly + PLB at week 52 (-3.23 [95% CI -5.79, -0.68]; P = 0.0134). FIB-4 showed reduction versus baseline only in the EXE once weekly + DAPA group at both week 28 (-0.06 [95% CI -0.11, -0.01]; P = 0.0135) and week 52 (-0.05 [95% CI -0.09, -0.004]; P = 0.0308).. The EXE once weekly + DAPA combination showed stronger effects than EXE once weekly + PLB or DAPA + PLB in ameliorating markers of hepatic steatosis and fibrosis in patients with type 2 diabetes. Prospective trials are needed to validate these findings.

Topics: Benzhydryl Compounds; Biomarkers; Diabetes Mellitus, Type 2; Exenatide; Fibrosis; Glucosides; Humans; Hypoglycemic Agents; Non-alcoholic Fatty Liver Disease; Prospective Studies

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, is a risk factor for endothelial dysfunction, a common pathophysiological denominator for both atherogenesis and cardiac fibrosis. We aimed to investigate whether the cardioprotective and antifibrotic effects of incretin drugs, exenatide and sitagliptin, may be associated with their ability to affect circulating and cardiac ADMA metabolism. Normal and fructose-fed rats were treated with sitagliptin (5.0/10 mg/kg) or exenatide (5/10 µg/kg) for 4 weeks. The following methods were used: LC-MS/MS, ELISA, Real-Time-PCR, colorimetry, IHC and H&E staining, PCA and OPLS-DA projections. Eight-week fructose feeding resulted in an increase in plasma ADMA and a decrease in NO concentration. Exenatide administration into fructose-fed rats reduced the plasma ADMA level and increased NO level. In the heart of these animals exenatide administration increased NO and PRMT1 level, reduced TGF-ß1, α-SMA levels and COL1A1 expression. In the exenatide treated rats renal DDAH activity positively correlated with plasma NO level and negatively with plasma ADMA level and cardiac α-SMA concentration. Sitagliptin treatment of fructose-fed rats increased plasma NO concentration, reduced circulating SDMA level, increased renal DDAH activity and reduced myocardial DDAH activity. Both drugs attenuated the myocardial immunoexpression of Smad2/3/P and perivascular fibrosis. In the metabolic syndrome condition both sitagliptin and exenatide positively modulated cardiac fibrotic remodeling and circulating level of endogenous NOS inhibitors but had no effects on ADMA levels in the myocardium.

Topics: Amidohydrolases; Animals; Arginine; Biomarkers; Chromatography, Liquid; Dipeptidyl-Peptidase IV Inhibitors; Exenatide; Fibrosis; Fructose; Glucagon-Like Peptide 1; Hypoglycemic Agents; Metabolic Syndrome; Nitric Oxide; Protease Inhibitors; Rats; Sitagliptin Phosphate; Tandem Mass Spectrometry

The role of exendin-4 in brown adipose tissue (BAT) activation was not very clear. This study is to verify the role of BAT involved in renal benefits of exendin-4 in diabetes mellitus (DM).. In vivo, C57BL/6 mice were randomly divided into nondiabetic (control) and diabetic groups (DM). The diabetic mice were randomized into a control group (DM-Con), BAT-excision group (DM+Exc), exendin-4-treated group (DM+E4), and BAT-excision plus exendin-4-treated group (DM+Exc+E4). The weight, blood glucose and lipids, 24 h urine albumin and 8-OH-dG, and renal fibrosis were analyzed. In vitro, we investigated the role of exendin-4 in the differentiation process of 3T3-L1 and brown preadipocytes and its effect on the rat mesangial cells induced by oleate.. The expressions of UCP-1, PGC-1. Exendin-4 could decrease the renal lipid deposit and improve diabetic nephropathy via activating the renal AMPK pathway independent of BAT activation.

Topics: 3T3-L1 Cells; 8-Hydroxy-2'-Deoxyguanosine; Adenylate Kinase; Adipocytes, Brown; Adipogenesis; Adipose Tissue, Brown; Albuminuria; Animals; Blood Glucose; Blotting, Western; Body Weight; CD36 Antigens; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Disease Models, Animal; Exenatide; Fibrosis; Gene Expression; Incretins; Kidney; Lipase; Mesangial Cells; Mice; Mice, Inbred C57BL; Myofibroblasts; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Random Allocation; Rats; Real-Time Polymerase Chain Reaction; Triglycerides; Uncoupling Protein 1

Sirt1 is a potent inhibitor of both poly(ADP-ribose) polymerases1 (PARP1) and NF-kB. This study investigated the cardioprotective effect of exendin-4 on cardiac function and remodeling in rats after an expreimentally-induced myocardial infarction (MI) and explored if this protection involves SIRT1/PARP1 axis. Rats were divided into five groups (n = 10/each): sham, sham + exendin-4 (25 nmol/kg/day i.p.), MI (induced by LAD occlusion), MI + exendin-4, and sham + exendin-4 + EX527 (5 mg/2×/week) (a SIRT1 inhibitor). All treatments were given for 6 weeks post the induction of MI. In sham-operated and MI-induced rats, exendin-4 significantly upregulated Bcl-2 levels, enhanced activity, mRNA, and levels of SIRT1, inhibited activity, mRNA, and levels of PARP1, and reduced ROS generation and PARP1 acetylation. In MI-treated rats, these effects were associated with improved cardiac architectures and LV function, reduced collagen deposition, and reduced mRNA and total levels of TNF-α and IL-6, as well as, the activation of NF-κB p65. In addition, exendin-4 inhibited the interaction of PARP1 with p300, TGF-β1, Smad3, and NF-κB p65 and signficantly reduced mRNA and protein levels of collagen I/III and protein levels of MMP2/9. In conclusion, exendin-4 is a potent cardioprotective agent that prevents post-MI inflammation and cardiac remodeling by activating SIRT1-induced inhibition of PARP1.

Topics: Acetylation; Animals; Anti-Inflammatory Agents; Apoptosis; Disease Models, Animal; Exenatide; Fibrosis; Glucagon-Like Peptide-1 Receptor; Incretins; Male; Myocardial Infarction; Myocytes, Cardiac; NF-kappa B; Poly (ADP-Ribose) Polymerase-1; Rats, Wistar; Signal Transduction; Sirtuin 1; Ventricular Function, Left; Ventricular Remodeling

Exenatide (Exe) is a glucagon-like peptide (GLP)-1 receptor agonist that enhances insulin secretion and is associated with induction of satiety with weight loss. As mitochondrial dysfunction and lipotoxicity are central features of nonalcoholic steatohepatitis (NASH), we tested whether Exe improved mitochondrial function in this setting. We studied C57BL/6J mice fed for 24 weeks either a control- or high-fructose, high-trans-fat (TFD)-diet (i.e., a NASH model previously validated by our laboratory). For the final 8 weeks, mice were treated with Exe (30 µg/kg/day) or vehicle. Mitochondrial metabolism was assessed by infusion of [13C3]propionate, [3,4-13C2]glucose and NMR-based 13C-isotopomer analysis. Exenatide significantly decreased fasting plasma glucose, free fatty acids and triglycerides, as well as adipose tissue insulin resistance. Moreover, Exe reduced 23% hepatic glucose production, 15% tri-carboxylic acid (TCA) cycle flux, 20% anaplerosis and 17% pyruvate cycling resulting in a significant 31% decrease in intrahepatic triglyceride content (P = 0.02). Exenatide improved the lipidomic profile and decreased hepatic lipid byproducts associated with insulin resistance and lipotoxicity, such as diacylglycerols (TFD: 111 ± 13 vs Exe: 64 ± 13 µmol/g protein, P = 0.03) and ceramides (TFD: 1.6 ± 0.1 vs Exe: 1.3 ± 0.1 µmol/g protein, P = 0.03). Exenatide lowered expression of hepatic lipogenic genes (Srebp1C, Cd36) and genes involved in inflammation and fibrosis (Tnfa, Timp1). In conclusion, in a diet-induced mouse model of NASH, Exe ameliorates mitochondrial TCA cycle flux and significantly decreases insulin resistance, steatosis and hepatocyte lipotoxicity. This may have significant clinical implications to the potential mechanism of action of GLP-1 receptor agonists in patients with NASH. Future studies should elucidate the relative contribution of direct vs indirect mechanisms at play.

Topics: Adipose Tissue; Animals; Blood Glucose; Citric Acid Cycle; Diet, High-Fat; Exenatide; Fatty Acids, Nonesterified; Fibrosis; Gene Expression Profiling; Glucagon-Like Peptide 1; Hepatocytes; Hypoglycemic Agents; Inflammation; Insulin Resistance; Lipid Metabolism; Lipidomics; Lipids; Liver; Male; Mice; Mice, Inbred C57BL; Mitochondria; Non-alcoholic Fatty Liver Disease; Triglycerides

Extracellular vesicles (EVs), which contain microRNA (miRNA), constitute a novel means of cell communication that may contribute to the inevitable expansion of renal fibrosis during diabetic kidney disease (DKD). Exendin-4 is effective for treating DKD through its action on GLP1R. However, the effect of exendin-4 on EV miRNA expression and renal cell communication during the development of DKD remains unknown. In this study, we found that EVs derived from HK-2 cells pre-treated with exendin-4 and high glucose (Ex-HG), which were taken up by normal HK-2 cells, resulted in decreased levels of FN and Col-I compared with EVs from HK-2 cells pre-treated with HG alone. Furthermore, we found that pretreatment with HG and exendin-4 may have contributed to a decrease in miR-192 in both HK-2 cells and EVs in a p53-dependent manner. Finally, we demonstrated that the amelioration of renal fibrosis by exendin-4 occurred through a miR-192-GLP1R pathway, indicating a new pathway by which exendin-4 regulates GLP1R. The results of this study suggest that exendin-4 inhibits the transfer of EV miR-192 from HG-induced renal tubular epithelial cells to normal cells, thus inhibiting GLP1R downregulation and protecting renal cells. This study reports a new mechanism by which exendin-4 exerts a protective effect against DKD.

Topics: 3' Untranslated Regions; Cell Line; Down-Regulation; Epithelial Cells; Exenatide; Extracellular Vesicles; Fibrosis; Gene Knockdown Techniques; Glucagon-Like Peptide-1 Receptor; Glucose; Humans; Kidney Tubules; MicroRNAs; Models, Biological

We have demonstrated that glucagon like peptide-1 (GLP-1) protects the heart against ischemic injury. However, the physiological mechanism by which GLP-1 receptor (GLP-1R) initiates cardioprotection remains to be determined. The objective of this study is to elucidate the functional roles of MAPK kinase 3 (MKK3) and Akt-1 in mediating exendin-4-elicited protection in the infarcted hearts. Adult mouse myocardial infarction (MI) was created by ligation of the left descending artery. Wild-type, MKK3(-/-), Akt-1(-/-), and Akt-1(-/-);MKK3(-/-) mice were divided into one of several groups: 1) sham: animals underwent thoracotomy without ligation; 2) MI: animals underwent MI and received a daily dose of intraperitoneal injection of vehicle (saline); 3) MI + exendin-4: infarcted mice received daily injections of exendin-4, a GLP-1R agonist (0.1 mg/kg, ip). Echocardiographic measurements indicate that exendin-4 treatment resulted in the preservation of ventricular function and increases in the survival rate, but these effects were diminished in MKK3(-/-), Akt-1(-/-), and Akt-1(-/-);MKK3(-/-) mice. Exendin-4 treatments suppressed cardiac hypotrophy and reduced scar size and cardiac interstitial fibrosis, respectively, but these beneficial effects were lost in genetic elimination of MKK3, Akt-1, or Akt-1(-/-);MKK3(-/-) mice. GLP-1R stimulation stimulated angiogenic responses, which were also mitigated by deletion of MKK3 and Akt-1. Exendin-4 treatment increased phosphorylation of MKK3, p38, and Akt-1 at Ser129 but decreased levels of active caspase-3 and cleaved poly (ADP-ribose) polymerase; these proteins were diminished in MKK3(-/-), Akt-1(-/-), and Akt-1(-/-);MKK3(-/-) mice. These results reveal that exendin-4 treatment improves cardiac function, attenuates cardiac remodeling, and promotes angiogenesis in the infarcted myocardium through MKK3 and Akt-1 pathway.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Cardiomegaly; Cardiotonic Agents; Disease Models, Animal; Enzyme Activation; Exenatide; Fibrosis; MAP Kinase Kinase 3; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardium; Neovascularization, Physiologic; Peptides; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Stroke Volume; Time Factors; Venoms; Ventricular Function, Left; Ventricular Remodeling

The objective of this article is to investigate the renoprotecive effects of exendin-4 in a mouse model of unilateral ureteral obstruction (UUO) and explore the putative mechanisms.. Male Balbc mice underwent sham operation or UUO surgery, and then received intraperitoneal injection of vehicle or exendin-4, respectively. After 14 days, mice were sacrificed and the left kidneys were collected and analyzed by histology, immunohistochemistry, Western blot, quantitative real-time reverse transcription polymerase chain reaction, radioimmunoassay and enzyme-linked immunosorbent assay.. As compared to the sham group, mice that underwent UUO surgery developed more severe tubular injury and interstitial fibrosis, as well as higher expression of fibronectin (FN), collagen-1 (Col-1) and α-smooth muscle actin (α-SMA). Also, we observed higher expression of angiotensin-converting enzyme (ACE) while lower expression of angiotensin-converting enzyme 2 (ACE2), higher levels of intrarenal angiotensin II (Ang II) while lower levels of intrarenal angiotensin-(1-7), and higher expression of transforming growth factor β1 (TGF-β1) and phosphorylation of Smad3 (p-Smad3) in the obstructed kidneys. Impressively, these pathologic changes were significantly attenuated in the mice group of UUO treated with exendin-4.. Our present study indicates for the first time that exendin-4 exerts renoprotective effects in an experimental model of UUO, partly through regulating the balance of the intrarenal renin-angiotensin system and then inhibiting the Ang II-mediated TGF-β1/Smad3 signaling pathway.

Topics: Actins; Angiotensin I; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Collagen Type I; Exenatide; Fibronectins; Fibrosis; Kidney; Male; Mice, Inbred BALB C; Peptide Fragments; Peptides; Peptidyl-Dipeptidase A; Renin-Angiotensin System; RNA, Messenger; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta1; Ureteral Obstruction; Venoms

Pancreatic stellate cells (PSCs) play a major role to fibrotic islet destruction observed in diabetic patients and animal model of diabetes. Exendin-4 (Ex-4) is a potent insulinotropic agent and has been approved for the treatment of type 2 diabetes. However, there have been no reports demonstrating the effects of Ex-4 on pancreatic islet fibrosis. In this study, Ex-4 treatment clearly attenuated fibrotic islet destruction and improved glucose tolerance and islet survival. GLP-1 receptor expression was upregulated during activation and proliferation of PSCs by hyperglycemia. The activation of PKA pathway by Ex-4 plays a role in ROS production and angiotensin II (Ang II) production. Exposure to high glucose stimulated ERK activation and Ang II-TGF- β1 production in PSCs. Interestingly, Ex-4 significantly reduced Ang II and TGF-β1 production by inhibition of ROS production but not ERK phosphorylation. Ex-4 may be useful not only as an anti-diabetic agent but also as an anti-fibrotic agent in type 2 diabetes due to its ability to inhibit PSC activation and proliferation and improve islet fibrosis in OLETF rats.

Topics: Angiotensin II; Animals; Cell Survival; Cyclic AMP-Dependent Protein Kinases; Exenatide; Fibrosis; Glucose; Glucose Intolerance; Islets of Langerhans; Pancreatic Stellate Cells; Peptides; Rats; Rats, Inbred OLETF; Reactive Oxygen Species; Signal Transduction; Transforming Growth Factor beta1; Venoms

Glucagon-like peptide-1 receptor (GLP-1R) agonist exendin-4 (Ex-4) is a remedy for type 2 diabetes mellitus (T2DM). Ex-4 ameliorates cardiac dysfunction induced by myocardial infarction in preclinical and clinical settings. However, it remains unclear whether Ex-4 may modulate diabetic cardiomyopathy. We tested the impact of Ex-4 on two types of diabetic cardiomyopathy models, genetic (KK) and acquired T2DM induced by high-fat diet [diet-induced obesity (DIO)], to clarify whether Ex-4 may combat independently of etiology. Each type of mice was divided into Ex-4 (24 nmol·kg(-1)·day(-1) for 40 days; KK-ex4 and DIO-ex4) and vehicle (KK-v and DIO-v) groups. Ex-4 ameliorated systemic and cardiac insulin resistance and dyslipidemia in both T2DM models. T2DM mice exhibited systolic (DIO-v) and diastolic (DIO-v and KK-v) left ventricular dysfunctions, which were restored by Ex-4 with reduction in left ventricular hypertrophy. DIO-v and KK-v exhibited increased myocardial fibrosis and steatosis (lipid accumulation), in which were observed cardiac mitochondrial remodeling and enhanced mitochondrial oxidative damage. Ex-4 treatment reversed these cardiac remodeling and oxidative stress. Cytokine array revealed that Ex-4-sensitive inflammatory cytokines were ICAM-1 and macrophage colony-stimulating factor. Ex-4 ameliorated myocardial oxidative stress via suppression of NADPH oxidase 4 with concomitant elevation of antioxidants (SOD-1 and glutathione peroxidase). In conclusion, GLP-1R agonism reverses cardiac remodeling and dysfunction observed in T2DM via normalizing imbalance of lipid metabolism and related inflammation/oxidative stress.

Topics: Animals; Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Diet, High-Fat; Disease Models, Animal; Dyslipidemias; Echocardiography, Doppler; Exenatide; Fibrosis; Glucagon-Like Peptide-1 Receptor; Glutathione Peroxidase; Hypertrophy, Left Ventricular; Hypoglycemic Agents; Inflammation Mediators; Infusions, Subcutaneous; Insulin Resistance; Intercellular Adhesion Molecule-1; Lipid Metabolism; Macrophage Colony-Stimulating Factor; Male; Mice; Mitochondria, Heart; Myocardium; NADPH Oxidase 4; NADPH Oxidases; Oxidative Stress; Peptides; Receptors, Glucagon; Superoxide Dismutase; Superoxide Dismutase-1; Time Factors; Venoms; Ventricular Dysfunction, Left; Ventricular Function, Left; Ventricular Remodeling