RESUMO
Anesthetics, particularly volatile anesthetics, have been shown to impair glucose metabolism and cause hyperglycemia, closely linking them with mortality and morbidity as related to surgery. Beyond being an anesthetic used for general anesthesia and sedation, intravenous hypnotic propofol displays an effect on glucose metabolism. To extend the scope of propofol studies, its effects on glucose metabolism were evaluated in male Sprague-Dawley rats of various ages. Unlike chloral hydrate and isoflurane, propofol had little effect on basal glucose levels in rats at 2 months of age, although it did reduce chloral hydrate- and isoflurane-induced hyperglycemia. Propofol reduced postload glucose levels after either intraperitoneal or oral administration of glucose in both 7- and 12-month-old rats, but not those at 2 months of age. These improved effects regarding propofol on glucose metabolism were accompanied by an increase in insulin, fibroblast growth factor-21 (FGF-21), and glucagon-like peptide-1 (GLP-1) secretion. Additionally, an increase in hepatic FGF-21 expression, GLP-1 signaling, and FGF-21 signaling, along with a decrease in endoplasmic reticulum (ER) stress, were noted in propofol-treated rats at 7 months of age. Current findings imply that propofol may turn into insulin-sensitizing molecules during situations of existing insulin resistance, which involve FGF-21, GLP-1, and ER stress.
Assuntos
Glicemia/efeitos dos fármacos , Fatores de Crescimento de Fibroblastos/biossíntese , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Glucose/metabolismo , Propofol/farmacologia , Animais , Modelos Animais de Doenças , Teste de Tolerância a Glucose , Hiperglicemia/sangue , Hiperglicemia/diagnóstico , Hiperglicemia/tratamento farmacológico , Hiperglicemia/etiologia , Insulina/metabolismo , Fígado , Masculino , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacosRESUMO
OBJECTIVES: Our study shows that glucagon-like peptide-1 (GLP-1) is secreted within human islets and may play an unexpectedly important paracrine role in islet physiology and pathophysiology. It is known that α cells within rodent and human pancreatic islets are capable of secreting GLP-1, but little is known about the functional role that islet-derived GLP-1 plays in human islets. METHODS: We used flow cytometry, immunohistochemistry, perifusions, and calcium imaging techniques to analyse GLP-1 expression and function in islets isolated from cadaveric human donors with or without type 2 diabetes. We also used immunohistochemistry to analyse GLP-1 expression within islets from pancreatic biopsies obtained from living donors. RESULTS: We have demonstrated that human islets secrete â¼50-fold more GLP-1 than murine islets and that â¼40% of the total human α cells contain GLP-1. Our results also confirm that dipeptidyl peptidase-4 (DPP4) is expressed in α cells. Sitagliptin increased GLP-1 secretion from cultured human islets but did not enhance glucose-stimulated insulin secretion (GSIS) in islets from non-diabetic (ND) or type 2 diabetic (T2D) donors, suggesting that ß cell GLP-1 receptors (GLP-1R) may already be maximally activated. Therefore, we tested the effects of exendin-9, a GLP-1R antagonist. Exendin-9 was shown to reduce GSIS by 39% and 61% in ND islets and T2D islets, respectively. We also observed significantly more GLP-1+ α cells in T2D islets compared with ND islets obtained from cadaveric donors. Furthermore, GLP-1+ α cells were also identified in pancreatic islet sections obtained from living donors undergoing surgery. CONCLUSIONS: In summary, we demonstrated that human islets secrete robust amounts of GLP-1 from an α cell subpopulation and that GLP-1R signalling may support GSIS to a greater extent in T2D islets.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Células Secretoras de Glucagon/metabolismo , Ilhotas Pancreáticas/metabolismo , Animais , Biomarcadores , Diabetes Mellitus Tipo 2/etiologia , Expressão Gênica , Glucagon/metabolismo , Peptídeo 1 Semelhante ao Glucagon/genética , Glucose/metabolismo , Humanos , Imunofenotipagem , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Ilhotas Pancreáticas/citologia , CamundongosRESUMO
Maintenance of glucose homeostasis is reciprocally regulated by insulin and glucagon-like peptide-1 (GLP-1). We previously reported that GLP-1 secretion in response to an oral glucose load was impaired following an administration of 3-deoxyglucosone (3DG), an independent factor associated with the development of pre-diabetes. Here we investigated the effects of 3DG on insulin signaling and insulin-induced GLP-1 secretion under high-glucose conditions in the enteroendocrine L cell line STC-1. STC-1 cells were exposed to 3DG (80, 300, and 1000 ng/ml) in the presence of 10-7 M insulin and 25 mM glucose. GLP-1 secretion was determined by ELISA, glucose uptake was monitored with 2-NBDG (2-(N(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxyglucose), glucose consumption was detected by glucoseoxidase, and protein expression of insulin signaling molecules was examined by western blot. Results showed a decrease in insulin-induced GLP-1 secretion and insulin receptor phosphorylation after 3DG treatment. Concomitantly, 3DG treatment inhibited insulin-induced phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) pathway activation. In the presence, but not absence, of insulin, 3DG treatment decreased insulin-stimulated glucose consumption. Inhibition of PI3K with Wortmannin attenuated insulin-induced increment in glucose transporter 2 (GLUT2) expression and 2-NBDG uptake. Accordingly, insulin-induced increase in GLUT2 expression and 2-NBGD uptake was significantly inhibited by 3DG treatment. 3DG-mediated reduction in GLUT2 expression contributes to the attenuation of insulin-induced GLP-1 secretion under high-glucose conditions in part through the insulin-PI3K/Akt/GLUT2 pathway in STC-1 cells. We conclude that 3DG interferes with insulin signaling and attenuates insulin action on glucose-induced GLP-1 secretion in STC-1 cells.
Assuntos
Desoxiglucose/análogos & derivados , Células Enteroendócrinas/metabolismo , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Glucose/metabolismo , Insulina/metabolismo , Transdução de Sinais , Animais , Linhagem Celular , Desoxiglucose/metabolismo , Transportador de Glucose Tipo 2/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor de Insulina/metabolismoRESUMO
5rolGLP-HV is a promising dual-function peptide for the treatment of diabetes and thrombosis simultaneously. For investigating the therapeutic mechanism of 5rolGLP-HV for type 2 diabetes mellitus (T2DM), STZ-induced diabetic mice were established and treated with 5rolGLP-HV. The results showed that daily water and food intake, blood glucose, serum and pancreatic insulin levels significantly decreased after 5rolGLP-HV treatment with various oral concentrations, and 16 mg/kg was the optimal dose for controlling diabetes. 5rolGLP-HV treatment decreased the MDA levels and the T-SOD activity in serum and pancreatic of diabetic mice (but not up to significant difference), and significantly increased the expression of signal pathways related genes of rolGLP-1, also the density of insulin expression and the numbers of apoptosis cells in islets of diabetic mice were significantly decreased in comparison to the negative diabetic mice. These effects above may be clarified the hypoglycemic mechanisms of 5rolGLP-HV, and 5rolGLP-HV may be as a potential drug for diabetes in future.
Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Hipoglicemiantes/farmacologia , Insulina/sangue , Proteínas Recombinantes/farmacologia , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Ingestão de Líquidos/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Ingestão de Alimentos/efeitos dos fármacos , Regulação da Expressão Gênica , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Hirudinas/química , Hipoglicemiantes/metabolismo , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Ilhotas Pancreáticas/patologia , MAP Quinase Quinase Quinases/genética , MAP Quinase Quinase Quinases/metabolismo , Masculino , Malondialdeído/antagonistas & inibidores , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Recombinantes/biossíntese , Estreptozocina , Superóxido Dismutase/metabolismoRESUMO
A new strategy under development for the treatment of type 2 diabetes and obesity is to mimic some of the effects of bariatric surgery by delivering food-related stimuli to the distal gastrointestinal tract where they should enhance the release of gut hormones such as glucagon-like peptide-1 (GLP-1) and peptideYY (PYY). Methods include inhibition of food digestion and absorption in the upper GI tract, or oral delivery of stimuli in capsules or pelleted form to protect them against gastric degradation. A variety of agents have been tested in humans using capsules, microcapsules or pellets, delivering nutrients, bile acids, fatty acids and bitter compounds. This review examines the outcomes of these different approaches and supporting evidence from intestinal perfusion studies.
Assuntos
Diabetes Mellitus Tipo 2/tratamento farmacológico , Trato Gastrointestinal/efeitos dos fármacos , Incretinas/uso terapêutico , Obesidade/tratamento farmacológico , Cirurgia Bariátrica , Diabetes Mellitus Tipo 2/metabolismo , Interações Alimento-Droga , Trato Gastrointestinal/metabolismo , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Peptídeo 1 Semelhante ao Glucagon/efeitos dos fármacos , Humanos , Incretinas/química , Obesidade/metabolismo , Peptídeo YY/efeitos dos fármacos , Peptídeo YY/metabolismo , SecretagogosRESUMO
AIMS: Enhancement of glucagon-like peptide-1 (GLP-1) reduces glucose levels and preserves pancreatic ß-cell function, but its effect against restenosis is unknown. METHODS AND RESULTS: We investigated the effect of subcutaneous injection of exenatide or local delivery of a recombinant adenovirus expressing GLP-1 (rAd-GLP-1) into carotid artery, in reducing the occurrence of restenosis following balloon injury. As a control, we inserted ß-galactosidase cDNA in the same vector (rAd-ßGAL). Otsuka Long-Evans Tokushima rats were assigned to three groups (n = 12 each): (1) normal saline plus rAd-ßGAL delivery (NS + rAd-ßGAL), (2) exenatide plus rAd-ßGAL delivery (Exenatide + rAd-ßGAL), and (3) normal saline plus rAd-GLP-1 delivery (NS + rAd-GLP-1). Normal saline or exenatide were administered subcutaneously from 1 week before to 2 weeks after carotid injury. After 3 weeks, the NS + rAd-ßGAL group showed the highest intima-media ratio (IMR; 3.73 ± 0.90), the exenatide + rAd-ßGAL treatment was the next highest (2.80 ± 0.51), and NS + rAd-GLP-1 treatment showed the lowest IMR (1.58 ± 0.48, P < 0.05 vs. others). The proliferation and migration of vascular smooth muscle cells and monocyte adhesion were decreased significantly after rAd-GLP-1 treatment, showing the same overall patterns as the IMR. In injured vessels, the apoptosis was greater and MMP2 expression was less in the NS + rAd-GLP-1 than in the exenatide or rAd-ßGAL groups. In vitro expressions of matrix metalloproteinases-2 and monocyte chemoattractant protein-1 and nuclear factor-kappa-B-p65 translocation were decreased more in the NS + rAd-GLP-1 group than in the other two groups (all P < 0.05). CONCLUSION: Direct GLP-1 overexpression showed better protection against restenosis after balloon injury via suppression of vascular smooth muscle cell migration, increased apoptosis, and decreased inflammatory processes than systemic exenatide treatment. This has potential therapeutic implications for treating macrovascular complications in diabetes.
Assuntos
Adenoviridae/genética , Lesões das Artérias Carótidas/terapia , Artéria Carótida Externa/metabolismo , Estenose Coronária/prevenção & controle , Diabetes Mellitus/terapia , Técnicas de Transferência de Genes , Terapia Genética , Vetores Genéticos , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Neointima , Animais , Apoptose , Lesões das Artérias Carótidas/genética , Lesões das Artérias Carótidas/metabolismo , Lesões das Artérias Carótidas/patologia , Artéria Carótida Externa/patologia , Adesão Celular , Movimento Celular , Proliferação de Células , Células Cultivadas , Estenose Coronária/genética , Estenose Coronária/metabolismo , Estenose Coronária/patologia , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Modelos Animais de Doenças , Exenatida , Peptídeo 1 Semelhante ao Glucagon/genética , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/patologia , Hipoglicemiantes/administração & dosagem , Incretinas/administração & dosagem , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Peptídeos/administração & dosagem , Ratos Endogâmicos OLETF , Fator de Transcrição RelA/metabolismo , Transfecção , Peçonhas/administração & dosagemRESUMO
Restoration of dysbiosed gut microbiota through probiotic may have profound effect on type 2 diabetes. In the present study, rats were fed high fat diet (HFD) for 3 weeks and injected with low dose streptozotocin to induce type 2 diabetes. Diabetic rats were then fed Lactobacillus rhamnosus NCDC 17 and L. rhamnosus GG with HFD for six weeks. L. rhamnosus NCDC 17 improved oral glucose tolerance test, biochemical parameters (fasting blood glucose, plasma insulin, glycosylated haemoglobin, free fatty acids, triglycerides, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol), oxidative stress (thiobarbituric acid reactive substance and activities of catalase, superoxide dismutase and glutathione peroxidase in blood and liver), bifidobacteria and lactobacilli in cecum, expression of glucagon like peptide-1 producing genes in cecum, and adiponection in epididymal fat, while decreased propionate proportions (%) in caecum, and expression of tumour necrosis factor-α and interlukin-6 in epididymal fat of diabetic rats as compared to diabetes control group. These findings offered a base for the use of L. rhamnosus NCDC 17 for the improvement and early treatment of type 2 diabetes.
Assuntos
Produtos Fermentados do Leite/microbiologia , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 2/terapia , Lacticaseibacillus rhamnosus , Probióticos/uso terapêutico , Adiponectina/biossíntese , Animais , Glicemia/metabolismo , Ceco/microbiologia , Diabetes Mellitus Tipo 2/induzido quimicamente , Dieta Hiperlipídica , Suplementos Nutricionais/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Teste de Tolerância a Glucose , Interleucina-6/biossíntese , Masculino , Estresse Oxidativo , Propionatos/metabolismo , Ratos , Ratos Wistar , Estreptozocina , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Glucagon-like peptide-1 (GLP-1) is a product of proglucagon cleavage synthesized in L cells in the intestinal mucosa, α-cells in the pancreatic islet, and neurons in the nucleus of the solitary tract. GLP-1 is essential for normal glucose tolerance and acts through a specific GLP-1 receptor that is expressed by islet ß-cells as well as other cell types. Because plasma concentrations of GLP-1 increase following meal ingestion it has been generally presumed that GLP-1 acts as a hormone, communicating information from the intestine to the endocrine pancreas through the circulation. However, there are a number of problems with this model including low circulating concentrations of GLP-1 in plasma, limited changes after meal ingestion and rapid metabolism in the plasma. Moreover, antagonism of systemic GLP-1 action impairs insulin secretion in the fasting state, suggesting that the GLP-1r is active even when plasma GLP-1 levels are low and unchanging. Consistent with these observations, deletion of the GLP-1r from islet ß-cells causes intolerance after IP or IV glucose, challenges that do not induce GLP-1 secretion. Taken together, these data support a model whereby GLP-1 acts through neural or paracrine mechanisms to regulate physiologic insulin secretion. In contrast, bariatric surgery seems to be a condition in which circulating GLP-1 could have an endocrine effect. Both gastric bypass and sleeve gastrectomy are associated with substantial increases in postprandial GLP-1 release and in these conditions interference with GLP-1r signaling has a significant impact on glucose regulation after eating. Thus, with either bariatric surgery or treatment with long-acting GLP-1r agonists, circulating peptide mediates insulinotropic activity. Overall, a case can be made that physiologic actions of GLP-1 are not hormonal, but that an endocrine mechanism of GLP-1r activation can be co-opted for therapeutics.
Assuntos
Peptídeo 1 Semelhante ao Glucagon/fisiologia , Receptor do Peptídeo Semelhante ao Glucagon 1/fisiologia , Insulina/metabolismo , Animais , Jejum , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Células Secretoras de Glucagon/metabolismo , Humanos , Incretinas/fisiologia , Secreção de Insulina , Proglucagon/metabolismoRESUMO
BACKGROUND & AIMS: Glucose-dependent insulinotropic peptide (GIP) induces production of interleukin 6 (IL6) by adipocytes. IL6 increases production of glucagon-like peptide (GLP)-1 by L cells and α cells, leading to secretion of insulin from ß cells. We investigated whether GIP regulates GLP1 and glycemia via IL6. METHODS: We obtained samples of human pancreatic islets and isolated islets from mice; human α cells and ß cells were sorted by flow cytometry and incubated with GIP. Islets were analyzed by quantitative polymerase chain reaction and immunohistochemistry. BKS.Cg-Dock7m+/+ Leprdb/J db/db mice (diabetic mice) and db/+ mice, as well as C57BL/6J IL6-knockout mice (IL6-KO) and C57BL/6J mice with the full-length Il6 gene (controls), were fed a chow or a high-fat diet; some mice were given injections of recombinant GIP, IL6, GLP, a neutralizing antibody against IL6 (anti-IL6), lipopolysaccharide, and/or IL1B. Mice were given a glucose challenge and blood samples were collected and analyzed. RESULTS: Incubation of mouse and human pancreatic α cells with GIP induced their production of IL6, leading to production of GLP1 and insulin secretion from pancreatic islets. This did not occur in islets from IL6-KO mice or in islets incubated with anti-IL6. Incubation of islets with IL1B resulted in IL6 production but directly reduced GLP1 production. Incubation of mouse islets with the sodium glucose transporter 2 inhibitor dapagliflozin induced production of GLP1 and IL6. Injection of control mice with GIP increased plasma levels of GLP1, insulin, and glucose tolerance; these effects were amplified in mice given lipopolysaccharide but reduced in IL6-KO mice or in mice given anti-IL6. Islets from diabetic mice had increased levels of IL1B and IL6, compared with db/+ mice, but injection of GIP did not lead to production of GLP1 or reduce glycemia. CONCLUSIONS: In studies of pancreatic islets from human beings and mice, we found that GIP induces production of IL6 by α cells, leading to islet production of GLP1 and insulin. This process is regulated by inflammation, via IL1B, and by sodium glucose transporter 2. In diabetic mice, increased islet levels of IL6 and IL1B might increase or reduce the production of GLP1 and affect glycemia.
Assuntos
Polipeptídeo Inibidor Gástrico/metabolismo , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Células Secretoras de Glucagon/metabolismo , Células Secretoras de Insulina/metabolismo , Interleucina-6/metabolismo , Animais , Glicemia/metabolismo , Diabetes Mellitus Experimental/etiologia , Diabetes Mellitus Experimental/metabolismo , Humanos , Insulina/metabolismo , Secreção de Insulina , Camundongos , Camundongos Endogâmicos C57BLRESUMO
INTRODUCTION: The gastrointestinal hormone GLP-1 is released from enteroendocrine L-cells and augments postprandial insulin secretion. In patients with type 2 diabetes, the incretin effect is markedly diminished. It is unclear, whether this is due to a reduction in the abundance of L-cells in the intestine. METHODS: Ileal tissue samples from 10 patients with and 10 patients without diabetes that underwent surgery for the removal of colon tumors were included. Tissue sections were stained for GLP-1, Ki67, TUNEL and chromogranin A. RESULTS: The number of L-cells was not different between patients with and without diabetes in either crypts (1.81±0.21% vs. 1.49±0.24%, respectively; p=0.31) or villi (1.07±0.16% vs. 0.83±0.10%, respectively; p=0.23). L-cell number was higher in crypts than in villi (p<0.0001). L-cell replication was detected rarely and not different between the groups. L-cell apoptosis was similar in patients with and without diabetes in both crypts (7.84±2.77% vs. 8.65±3.77%, p=0.85) and villi (4.48±2.89% vs. 8.62±4.64%, p=0.42). Chromogranin A staining was found in a subset of L-cells only. CONCLUSIONS: Intestinal L-cell density is higher in crypts than in villi. Chromogranin A is not a prerequisite for GLP-1 production. L-cell density and turnover are not different between patients with and without diabetes. Thus, alterations in the number of GLP-1 producing cells do not explain the reduced incretin effect in patients with type 2 diabetes.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Células Enteroendócrinas/metabolismo , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Íleo/metabolismo , Mucosa Intestinal/metabolismo , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/metabolismo , Contagem de Células , Cromogranina A/análise , Cromogranina A/metabolismo , Feminino , Humanos , Íleo/citologia , Mucosa Intestinal/citologia , Antígeno Ki-67 , Masculino , Pessoa de Meia-IdadeRESUMO
The physiological role of the TGR5 receptor in the pancreas is not fully understood. We previously showed that activation of TGR5 in pancreatic ß cells by bile acids induces insulin secretion. Glucagon released from pancreatic α cells and glucagon-like peptide 1 (GLP-1) released from intestinal L cells regulate insulin secretion. Both glucagon and GLP-1 are derived from alternate splicing of a common precursor, proglucagon by PC2 and PC1, respectively. We investigated whether TGR5 activation in pancreatic α cells enhances hyperglycemia-induced PC1 expression thereby releasing GLP-1, which in turn increases ß cell mass and function in a paracrine manner. TGR5 activation augmented a hyperglycemia-induced switch from glucagon to GLP-1 synthesis in human and mouse islet α cells by GS/cAMP/PKA/cAMP-response element-binding protein-dependent activation of PC1. Furthermore, TGR5-induced GLP-1 release from α cells was via an Epac-mediated PKA-independent mechanism. Administration of the TGR5 agonist, INT-777, to db/db mice attenuated the increase in body weight and improved glucose tolerance and insulin sensitivity. INT-777 augmented PC1 expression in α cells and stimulated GLP-1 release from islets of db/db mice compared with control. INT-777 also increased pancreatic ß cell proliferation and insulin synthesis. The effect of TGR5-mediated GLP-1 from α cells on insulin release from islets could be blocked by GLP-1 receptor antagonist. These results suggest that TGR5 activation mediates cross-talk between α and ß cells by switching from glucagon to GLP-1 to restore ß cell mass and function under hyperglycemic conditions. Thus, INT-777-mediated TGR5 activation could be leveraged as a novel way to treat type 2 diabetes mellitus.
Assuntos
Ácidos Cólicos/farmacologia , Diabetes Mellitus Experimental/genética , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Glucose/metabolismo , Comunicação Parácrina/genética , Receptores Acoplados a Proteínas G/agonistas , Animais , Derivados de Benzeno/farmacologia , Benzenossulfonatos/farmacologia , Linhagem Celular , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Estrenos/farmacologia , Regulação da Expressão Gênica , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Peptídeo 1 Semelhante ao Glucagon/genética , Células Secretoras de Glucagon/efeitos dos fármacos , Células Secretoras de Glucagon/metabolismo , Células Secretoras de Glucagon/patologia , Homeostase/efeitos dos fármacos , Humanos , Resistência à Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pró-Proteína Convertase 1/genética , Pró-Proteína Convertase 1/metabolismo , Pró-Proteína Convertase 2/genética , Pró-Proteína Convertase 2/metabolismo , Pirrolidinonas/farmacologia , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Sulfonas/farmacologiaRESUMO
PURPOSE: Sleeve gastrectomy is an effective technique for the treatment of severe obesity, and its effects on the improved ß-cell function have not yet been fully understood. MATERIALS AND METHODS: From February 2014 to July 2015, sleeve gastrectomy was performed in 5 patients with T2D, who were assessed before and after sleeve gastrectomy (SG). Moreover, a high-fat-diet (HFD) mouse model was also used to study the molecular mechanisms of ß-cell functional improvement after SG. RESULTS: The glucose-stimulated acute insulin response was restored in the T2D patients after SG. The expression of GLP-1 in colonic tissue as well as ß-cell specific transcription factors (TFs), Pdx1, and MafA in islets was significantly increased after SG. CONCLUSION: ß-cell dysfunction can be ameliorated by SG. The re-activation of key TFs contributes to the improvement of ß cell function.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Gastrectomia , Proteínas de Homeodomínio/biossíntese , Células Secretoras de Insulina/metabolismo , Fatores de Transcrição Maf Maior/biossíntese , Obesidade Mórbida/cirurgia , Transativadores/biossíntese , Idoso , Animais , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/cirurgia , Dieta Hiperlipídica , Modelos Animais de Doenças , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade Mórbida/complicações , Obesidade Mórbida/metabolismo , Fatores de Transcrição/biossíntese , Regulação para CimaRESUMO
Selective GLP-1 secretagogues represent a novel potential therapy for type 2 diabetes mellitus. This study examined the GLP-1 secretory activity of the ethnomedicinal plant, Fagonia cretica, which is postulated to possess anti-diabetic activity. After extraction and fractionation extracts and purified compounds were tested for GLP-1 and GIP secretory activity in pGIP/neo STC-1 cells. Intracellular levels of incretin hormones and their gene expression were also determined. Crude F. cretica extracts stimulated both GLP-1 and GIP secretion, increased cellular hormone content, and upregulated gene expression of proglucagon, GIP and prohormone convertase. However, ethyl acetate partitioning significantly enriched GLP-1 secretory activity and this fraction underwent bioactivity-guided fractionation. Three isolated compounds were potent and selective GLP-1 secretagogues: quinovic acid (QA) and two QA derivatives, QA-3ß-O-ß-D-glycopyranoside and QA-3ß-O-ß-D-glucopyranosyl-(28â1)-ß-D-glucopyranosyl ester. All QA compounds activated the TGR5 receptor and increased intracellular incretin levels and gene expression. QA derivatives were more potent GLP-1 secretagogues than QA. This is the first time that QA and its naturally-occurring derivatives have been shown to activate TGR5 and stimulate GLP-1 secretion. These data provide a plausible mechanism for the ethnomedicinal use of F. cretica and may assist in the ongoing development of selective GLP-1 agonists.
Assuntos
Células Enteroendócrinas/efeitos dos fármacos , Polipeptídeo Inibidor Gástrico/agonistas , Peptídeo 1 Semelhante ao Glucagon/agonistas , Hipoglicemiantes/farmacologia , Proglucagon/agonistas , Zygophyllaceae/química , Linhagem Celular , Células Enteroendócrinas/citologia , Células Enteroendócrinas/metabolismo , Polipeptídeo Inibidor Gástrico/biossíntese , Polipeptídeo Inibidor Gástrico/genética , Polipeptídeo Inibidor Gástrico/metabolismo , Regulação da Expressão Gênica , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Peptídeo 1 Semelhante ao Glucagon/genética , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Glicosídeos/isolamento & purificação , Glicosídeos/farmacologia , Humanos , Hipoglicemiantes/isolamento & purificação , Incretinas/agonistas , Incretinas/genética , Incretinas/metabolismo , Componentes Aéreos da Planta/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Proglucagon/biossíntese , Proglucagon/genética , Pró-Proteína Convertases/genética , Pró-Proteína Convertases/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Triterpenos/isolamento & purificação , Triterpenos/farmacologiaRESUMO
BACKGROUND AND IMPORTANCE: Local biological drug delivery in the brain is an innovative field of medicine that developed rapidly in recent years. Our report illustrates a unique case of de novo development of a cerebral arteriovenous malformation (AVM) after implantation of genetically modified allogeneic mesenchymal stem cells in the brain. CLINICAL PRESENTATION: A 50-year-old man was included in a prospective clinical study (study ID number CM GLP-1/01, 2007-004516-31) investigating a novel neuroprotective approach in stroke patients to prevent perihematomal neuronal damage. In this study, alginate microcapsules containing genetically modified allogeneic mesenchymal stem cells producing the neuroprotective glucagon-like peptide-1 (GLP-1) were implanted. Three years later, the patient presented with aphasia and a focal seizure due to a new left frontal intracerebral hemorrhage. Angiography revealed a de novo left frontal AVM. CONCLUSION: The development of an AVM within a period of 3 years after implantation of the glucagon-like peptide-1-secreting mesenchymal stem cells suggests a possible relationship. This case exemplifies that further investigations are necessary to assess the safety of genetically modified cell lines for local biological drug delivery in the brain.
Assuntos
Encéfalo/patologia , Malformações Arteriovenosas Intracranianas/etiologia , Malformações Arteriovenosas Intracranianas/patologia , Transplante de Células-Tronco Mesenquimais/efeitos adversos , Afasia/etiologia , Cápsulas , Hemorragia Cerebral/etiologia , Terapia Genética/efeitos adversos , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Peptídeo 1 Semelhante ao Glucagon/genética , Humanos , Malformações Arteriovenosas Intracranianas/cirurgia , Masculino , Pessoa de Meia-Idade , Neurônios/patologia , Convulsões/etiologia , Acidente Vascular Cerebral/cirurgia , Resultado do TratamentoRESUMO
Protein engineering has been successfully applied in protein drug discovery. Using this technology, we previously have constructed a fusion protein by linking the globular domain of adiponectin to the C-terminus of a glucagon-like peptide-1 (GLP-1) analog. Herein, to further improve its bioactivity, we reconstructed this fusion protein by introducing linker peptides of different length and flexibility. The reconstructed fusion proteins were overexpressed in Escherichia coli and purified using nickel affinity chromatography. Their agonist activity towards receptors of GLP-1 and adiponectin were assessed in vitro by using luciferase assay and AMP-activated protein kinase (AMPK) immunoblotting, respectively. The effects of the selected fusion protein on glucose and lipid metabolism were evaluated in mice. The fusion protein reconstructed using a linker peptide of AMGPSSGAPGGGGS showed high potency in activating GLP-1 receptor and triggering AMPK phosphorylation via activating the adiponectin receptor. Remarkably, the optimized fusion protein was highly effective in lowering blood glucose and lipids in mice. Collectively, these findings demonstrate that the bioactivity of this GLP-1 fusion protein can be significantly promoted by linker engineering, and indicate that the optimized GLP-1 fusion protein is a promising lead structure for anti-diabetic drug discovery.
Assuntos
Adiponectina/genética , Peptídeo 1 Semelhante ao Glucagon/genética , Engenharia de Proteínas/métodos , Proteínas Quinases Ativadas por AMP/metabolismo , Adiponectina/biossíntese , Adiponectina/farmacologia , Adiponectina/uso terapêutico , Animais , Gorduras na Dieta/metabolismo , Escherichia coli , Genes Reporter , Genes Sintéticos , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Peptídeo 1 Semelhante ao Glucagon/farmacologia , Peptídeo 1 Semelhante ao Glucagon/uso terapêutico , Receptor do Peptídeo Semelhante ao Glucagon 1/efeitos dos fármacos , Hiperglicemia/sangue , Hiperglicemia/tratamento farmacológico , Hiperlipidemias/sangue , Hiperlipidemias/tratamento farmacológico , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Lipídeos/sangue , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Azeite de Oliva/metabolismo , Peptídeos/genética , Fosforilação , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/farmacologia , Proteínas Recombinantes de Fusão/uso terapêuticoRESUMO
The incretin hormones glucagon-like peptide-1 (GLP1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from intestinal endocrine cells, the so-called L- and K-cells. The cells are derived from a common precursor and are highly related, and co-expression of the two hormones in so-called L/K-cells has been reported. To investigate the relationship between the GLP1- and GIP-producing cells more closely, we generated a transgenic mouse model expressing a fluorescent marker in GIP-positive cells. In combination with a mouse strain with fluorescent GLP1 cells, we were able to estimate the overlap between the two cell types. Furthermore, we used primary cultured intestinal cells and isolated perfused mouse intestine to measure the secretion of GIP and GLP1 in response to different stimuli. Overlapping GLP1 and GIP cells were rare (â¼5%). KCl, glucose and forskolin+IBMX increased the secretion of both GLP1 and GIP, whereas bombesin/neuromedin C only stimulated GLP1 secretion. Expression analysis showed high expression of the bombesin 2 receptor in GLP1 positive cells, but no expression in GIP-positive cells. These data indicate both expressional and functional differences between the GLP1-producing 'L-cell' and the GIP-producing 'K-cell'.
Assuntos
Células Enteroendócrinas/classificação , Células Enteroendócrinas/metabolismo , Polipeptídeo Inibidor Gástrico/biossíntese , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Receptores da Bombesina/análise , Animais , Cálcio/análise , Separação Celular , Células Cultivadas , Células Enteroendócrinas/química , Feminino , Citometria de Fluxo , Corantes Fluorescentes , Polipeptídeo Inibidor Gástrico/análise , Polipeptídeo Inibidor Gástrico/metabolismo , Peptídeo 1 Semelhante ao Glucagon/análise , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Integrases/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptores da Bombesina/genéticaRESUMO
Previous reports indicate that caloric restriction attenuates anxiety and other behavioral responses to acute stress, and blunts the ability of stress to increase anterior pituitary release of adrenocorticotropic hormone. Since hindbrain glucagon-like peptide-1 (GLP-1) neurons and noradrenergic prolactin-releasing peptide (PrRP) neurons participate in behavioral and endocrine stress responses, and are sensitive to the metabolic state, we examined whether overnight food deprivation blunts stress-induced recruitment of these neurons and their downstream hypothalamic and limbic forebrain targets. A single overnight fast reduced anxiety-like behavior assessed in the elevated-plus maze and acoustic startle test, including marked attenuation of light-enhanced startle. Acute stress [i.e., 30 min restraint (RES) or 5 min elevated platform exposure] robustly activated c-Fos in GLP-1 and PrRP neurons in fed rats, but not in fasted rats. Fasting also significantly blunted the ability of acute stress to activate c-Fos expression within the anterior ventrolateral bed nucleus of the stria terminalis (vlBST). Acute RES stress suppressed dark-onset food intake in rats that were fed ad libitum, whereas central infusion of a GLP-1 receptor antagonist blocked RES-induced hypophagia, and reduced the ability of RES to activate PrRP and anterior vlBST neurons in ad libitum-fed rats. Thus, an overnight fast "silences" GLP-1 and PrRP neurons, and reduces both anxiety-like and hypophagic responses to acute stress. The partial mimicking of these fasting-induced effects in ad libitum-fed rats after GLP-1 receptor antagonism suggests a potential mechanism by which short-term negative energy balance attenuates neuroendocrine and behavioral responses to acute stress. SIGNIFICANCE STATEMENT: The results from this study reveal a potential central mechanism for the "metabolic tuning" of stress responsiveness. A single overnight fast, which markedly reduces anxiety-like behavior in rats, reduces or blocks the ability of acute stress to activate hindbrain neurons that are immunoreactive for either prolactin-releasing peptide or glucagon-like peptide 1, and attenuates the activation of their stress-sensitive projection targets in the limbic forebrain. In nonfasted rats, central antagonism of glucagon-like peptide 1 receptors partially mimics the effect of an overnight fast by blocking the ability of acute stress to inhibit food intake, and by attenuating stress-induced activation of hindbrain and limbic forebrain neurons. We propose that caloric restriction attenuates behavioral and physiological responses to acute stress by "silencing" central glucagon-like peptide 1 signaling pathways.
Assuntos
Privação de Alimentos/fisiologia , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Rombencéfalo/metabolismo , Transdução de Sinais/fisiologia , Estresse Psicológico/metabolismo , Animais , Ansiedade/metabolismo , Restrição Calórica , Modelos Animais de Doenças , Imuno-Histoquímica , Masculino , Aprendizagem em Labirinto/fisiologia , Proteínas Proto-Oncogênicas c-fos/biossíntese , Ratos , Ratos Sprague-DawleyRESUMO
BACKGROUND: Obesity induces cardiovascular alterations, including cardiac hypertrophy, impaired relaxation, and heart rate variability (HRV), which are associated with increased mortality. Gastric bypass surgery (GBP) reduces cardiovascular mortality, but the mechanisms involved are not clearly established. To date, the implication of postsurgical hormonal changes has not been tested. Our aim was to study the relationships between the evolution of cardiovascular functions after GBP and changes in metabolic and hormonal parameters, including glucagon-like peptide-1 (GLP-1) and brain natriuretic peptide (N-terminal pro-brain natriuretic peptide (NT-proBNP)). METHODS: Echocardiographic parameters, 24-h rhythmic Holter recording, plasma concentrations of GLP-1 before and after a test meal, and fasting NT-proBNP were assessed in 34 patients (M/F 2/32, age 36 ± 11 years, BMI 46 ± 6 kg/m(2)), before and 1 year after GBP. RESULTS: After GBP, excess weight loss was 79 ± 20%. Blood pressure (BP), heart rate, and left ventricular mass decreased, while HRV and diastolic function (E/A ratio) improved. Plasma concentrations of NT-proBNP and postprandial (PP) GLP-1 increased. Changes in cardiovascular parameters were related to BMI and insulin sensitivity. Furthermore, the decrease in BP was independently associated with the increase of PP GLP-1 level and HRV was positively associated with NT-proBNP concentration after surgery. CONCLUSIONS: The increase in endogenous GLP-1 observed after GBP was associated with decreased BP but not with improvement of other cardiovascular parameters, whereas the increase in NT-proBNP, within the physiological range, was associated with improved HRV.
Assuntos
Derivação Gástrica , Peptídeo 1 Semelhante ao Glucagon/biossíntese , Peptídeo Natriurético Encefálico/biossíntese , Obesidade/metabolismo , Obesidade/cirurgia , Fragmentos de Peptídeos/biossíntese , Adulto , Pressão Sanguínea/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/fisiopatologia , Redução de Peso/fisiologiaRESUMO
According to the 2010 World Health Organization classification, all gastrointestinal neuroendocrine tumors (NETs) are classified as malignant except for L-cell-type (glucagon-like peptide [GLP] and peptide YY [PYY]-producing) NETs. However, L-cell immunophenotype in rectal NETs has not been widely studied previously. Immunohistochemical labeling of L-cell markers with GLP1 and PYY was performed in 208 surgically or endoscopically resected rectal NET cases with tissue microarrays and was compared with clinicopathologic features and patient survival. Rectal NETs with non-L-cell immunophenotype and large tumor size (>1 cm) were associated with increased tumor grading, advanced T category, lymphovascular and perineural invasions, and lymph node and distant metastases (P<0.001, each). Rectal NET patients with non-L-cell phenotype and measuring >1 cm had significantly worse survival outcome than other groups by univariate (P<0.001) and multivariate (P<0.001) analyses. In summary, non-L-cell immunophenotype and large tumor size are associated with increased tumor grading and staging, concurrently indicating that they are independently poor prognostic indicators in rectal NET patients. Therefore, combining L-cell phenotype and tumor size can demonstrate the clinical behavior of rectal NETs more precisely than use of L-cell immunophenotype alone.
Assuntos
Peptídeo 1 Semelhante ao Glucagon/biossíntese , Tumores Neuroendócrinos/patologia , Peptídeo YY/metabolismo , Neoplasias Retais/patologia , Adulto , Idoso , Feminino , Humanos , Imuno-Histoquímica , Imunofenotipagem , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Tumores Neuroendócrinos/metabolismo , Tumores Neuroendócrinos/mortalidade , Prognóstico , Modelos de Riscos Proporcionais , Neoplasias Retais/metabolismo , Neoplasias Retais/mortalidade , Análise Serial de Tecidos , Adulto JovemRESUMO
BACKGROUND: There have been a number of beneficial effects of incretin agonists on the cardiovascular system. Glycated albumin (GA) and tumor necrosis factor (TNFα) may lead to endothelial dysfunction. Due to reports of cardioprotective effects of incretin agonist, we wanted to determine if GLP-1 and exendin-4 can reverse diminished production of nitric oxide (NO) after treatment with TNFα and GA. The objective of our experiment was to study the interaction between incretin agonists and proinflammatory substances like TNFα and GA on production of NO in HCAEC. METHODS: Human vascular endothelial cells from the coronary artery (HCAEC) were used. The mRNA expression and protein level of endothelial nitric oxide synthase (eNOS) and inducible (iNOS) were quantified. NO production was measured in cells using DAF-FM/DA and flow cytometry. RESULTS: TNFα (10 ng/mL) decreased eNOS: mRNA by 90% and protein level by 31%. TNFα also decreased NO by 33%. GA (500 µg/mL) neither affected eNOS expression nor the protein level, but inhibited nearly all formation of NO in endothelium. GLP-1 (100 nM) and exendin-4 (1 and 10nM) decreased the amount of NO compared to control. Incubation of HCAEC with TNFα and incretin agonists did not change or moderately reduce the amount of NO compared to TNFα alone. CONCLUSIONS: TNFα and GA decrease production of NO in HCAEC, presumably by inducing reactive oxygen species or eNOS uncoupling. Incretin agonists in tested concentrations in the presence of l-arginine were not able to reverse this effect and instead led to a further reduction in NO production.