RESUMO
G protein-coupled receptor (GPR) 120 is expressed in enteroendocrine cells secreting glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide/gastric inhibitory polypeptide (GIP), and cholecystokinin (CCK). Although GPR120 signaling in adipose tissue and macrophages has been reported to ameliorate obesity and insulin resistance in a high long-chain triglyceride (LCT) diet, intestine-specific roles of GPR120 are unclear. To clarify the metabolic effect of GPR120 in the intestine, we generated intestine-specific GPR120-knockout (GPR120int-/-) mice. In comparison with floxed GPR120 (WT) mice, GPR120int-/- mice exhibited reduced GIP secretion and CCK action without change of insulin, GLP-1, or peptide YY (PYY) secretion after a single administration of LCT. Under a high-LCT diet, GPR120int-/- mice showed a mild reduction of body weight and substantial amelioration of insulin resistance and fatty liver. Moreover, liver and white adipose tissue (WAT) of GPR120int-/-mice exhibited increased Akt phosphorylation and reduced gene expression of suppressor of cytokine signaling (SOCS) 3, which inhibits insulin signaling. In addition, gene expression of inflammatory cytokines in WAT and lipogenic molecules in liver were reduced in GPR120int-/- mice. These findings suggest that inhibition of GPR120 signaling in intestine ameliorates insulin resistance and fatty liver under high-LCT diet feeding.NEW & NOTEWORTHY We generated novel intestine-specific GPR120-knockout (GPR120int-/-) mice and investigated the metabolic effect of GPR120 in the intestine. GPR120int-/- mice exhibited a reduction of GIP secretion and CCK action after a single administration of LCT. Under a high-LCT diet, GPR120int-/- mice showed mild improvement in obesity and marked amelioration of insulin resistance and hepatic steatosis. Our results indicate an important role of intestinal GPR120 on insulin resistance and hepatic steatosis.
Assuntos
Dieta Hiperlipídica , Intestinos , Receptores Acoplados a Proteínas G , Transdução de Sinais , Animais , Camundongos , Camundongos Endogâmicos C57BL , Intestinos/metabolismo , Resistência à Insulina , Triglicerídeos/administração & dosagem , Fígado Gorduroso/metabolismo , Camundongos Knockout , Glucose/administração & dosagem , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Obesidade/metabolismo , Óleo de Milho/administração & dosagemRESUMO
BACKGROUND: Effects of antihyperglycemic therapies on cardiovascular and heart failure (HF) risks have varied widely across cardiovascular outcome trials (CVOTs), and underlying factors remain incompletely understood. We aimed to determine the relationships of glycated hemoglobin (HbA1c) or bodyweight changes with these outcomes in all CVOTs of antihyperglycemic therapies. METHODS: We searched PubMed and EMBASE up to 25 January 2023 for all randomized controlled CVOTs of antihyperglycemic therapies reporting both major adverse cardiovascular events (MACE) and HF outcomes in patients with type 2 diabetes or prediabetes. We performed meta-regression analyses following random-effects meta-analyses to evaluate the effects of HbA1c or bodyweight reductions on each outcome. RESULTS: Thirty-five trials comprising 256,524 patients were included. Overall, antihyperglycemic therapies reduced MACE by 9% [risk ratio (RR): 0.91; 95% confidence interval (CI) 0.88-0.94; P < 0.001; I2 = 36.5%]. In meta-regression, every 1% greater reduction in HbA1c was associated with a 14% reduction in the RR of MACE (95% CI 4-24; P = 0.010), whereas bodyweight change was not associated with the RR of MACE. The magnitude of the reduction in MACE risk associated with HbA1c reduction was greater in trials with a higher baseline prevalence of atherosclerotic cardiovascular disease. On the other hand, antihyperglycemic therapies showed no overall significant effect on HF (RR: 0.95; 95% CI 0.87-1.04; P = 0.28; I2 = 75.9%). In a subgroup analysis based on intervention type, sodium-glucose cotransporter-2 inhibitors (SGLT2i) conferred the greatest HF risk reduction (RR: 0.68; 95% CI 0.62-0.75; P < 0.001; I2 = 0.0%). In meta-regression, every 1 kg bodyweight reduction, but not HbA1c reduction, was found to reduce the RR of HF by 7% (95% CI 4-10; P < 0.001); however, significant residual heterogeneity (P < 0.001) was observed, and SGLT2i reduced HF more than could be explained by HbA1c or bodyweight reductions. CONCLUSIONS: Antihyperglycemic therapies reduce MACE in an HbA1c-dependent manner. These findings indicate that HbA1c can be a useful marker of MACE risk reduction across a wide range of antihyperglycemic therapies, including drugs with pleiotropic effects. In contrast, HF is reduced not in an HbA1c-dependent but in a bodyweight-dependent manner. Notably, SGLT2i have shown class-specific benefits for HF beyond HbA1c or bodyweight reductions.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Insuficiência Cardíaca , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/epidemiologia , Hipoglicemiantes/efeitos adversos , Análise de Regressão , Inibidores do Transportador 2 de Sódio-Glicose/efeitos adversos , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
A tyrosine (Tyr)- or tryptophan (Trp)-selective metal-free C-H sulfenylation reaction using an acid-activated S-acetamidomethyl cysteine (Cys) sulfoxide, Cys(Acm)(O), has been achieved. The dually protonated intermediate produced from Cys(Acm)(O) under acidic conditions allows the sulfenylation of Tyr. Significantly, the reaction in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf) mainly affords a Cys-Tyr-linked peptide even in the presence of Trp residues. In contrast, a Cys-Trp-linked peptide was selectively obtained from the reaction in the presence of guanidine hydrochloride (Gn â HCl) under acidic conditions. Established Tyr- and Trp-selective sulfenylation methods were used in the Cys-Tyr stapling and Trp lipidation of glucagon-like peptides 1 in a one-pot/stepwise manner. Investigation of the mechanism showed that orbital- and charge-controlled reactions are responsible for the Trp and Tyr selectivity, respectively.
Assuntos
Cisteína , Peptídeos , Cisteína/química , Peptídeos/química , Tirosina/química , Sulfóxidos , GuanidinaRESUMO
Immune checkpoint inhibitors (ICIs) are used for various malignancies, although they frequently cause immune-related adverse events involving the thyroid gland (thyroid irAEs). We conducted a retrospective cohort study to elucidate thyroid function outcomes. Fifty of 639 patients who received PD-1 blockade therapy met criteria and were divided into the following groups: thyrotoxicosis with subsequent hypothyroidism (Toxic-Hypo, n = 21); thyrotoxicosis without subsequent hypothyroidism (Toxic, n = 9); and hypothyroidism without prior thyrotoxicosis (Hypo, n = 20). The Toxic-Hypo group developed thyroid irAEs earlier than the Toxic group (26 vs. 91 days; p < 0.001), and had higher serum free T4 levels (3.210 vs. 1.880 ng/dL; p = 0.011). In addition, positive anti-thyroglobulin antibodies (TgAbs) at thyroid irAE onset were more common in the Toxic-Hypo group (93.3%) than in the Toxic group (0.0%; p = 0.005) and Hypo group (44.4%; p = 0.007). The Toxic-Hypo group developed severe hypothyroidism and required larger levothyroxine (LT4) doses than the Hypo group (75 vs. 25 µg/day; p = 0.007). We predicted that patients with positive TgAbs who developed severe thyrotoxicosis within 4 weeks after the first ICI administration would develop subsequent hypothyroidism. We treated 4 such patients with prompt LT4 replacement, characterized by LT4 initiation after thyrotoxicosis improvement and quick dose titration. Their euthyroid state was successfully maintained, in contrast with patients receiving conventional replacement. In conclusion, rapid-onset severe thyrotoxicosis in patients with TgAbs correlated with a high likelihood of subsequent hypothyroidism. Accordingly, prompt LT4 replacement is suggested to prevent a severely hypothyroid state.
Assuntos
Hipotireoidismo , Tireotoxicose , Humanos , Tiroxina/uso terapêutico , Estudos Retrospectivos , Hipotireoidismo/tratamento farmacológico , Tireotoxicose/induzido quimicamente , Tireotoxicose/tratamento farmacológicoRESUMO
AIM: To evaluate the cardiovascular and renal outcomes of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and the associations between these outcomes and HbA1c or weight reduction. MATERIALS AND METHODS: We searched PubMed/MEDLINE, EMBASE, and CENTRAL databases for randomized, placebo-controlled trials of GLP-1 RAs reporting major adverse cardiovascular events (MACE; a composite of cardiovascular mortality, stroke, and myocardial infarction) as the primary outcome. We conducted a meta-regression analysis of primary and secondary outcomes with HbA1c or weight reduction following a meta-analysis with a random-effects model for these outcomes. RESULTS: We extracted data of 60 800 individuals from eight eligible studies (ELIXA, LEADER, SUSTAIN-6, EXSCEL, HARMONY, PIONEER 6, REWIND, and AMPLITUDE-O). GLP-1 RAs reduced MACE (hazard ratio [HR] 0.86; 95% CI: 0.80-0.93; P < .001) and secondary outcomes including the composite renal outcome (0.80; 0.73-0.87; P < .001). In meta-regression analysis, every 1% reduction in HbA1c was associated with 26% and 35% decreases in the logarithm of HR of MACE (P = .044; R2 = 0.65) and the composite renal outcome (P = .040; R2 = 0.85), respectively. On the contrary, weight reduction was not associated with any outcome, including MACE (P = .390). CONCLUSIONS: The reduction in HbA1c, but not body weight, is associated with cardiovascular and renal outcomes. The magnitude of HbA1c reduction can be a surrogate for the cardiovascular and renal benefits of treatment with GLP-1 RAs.
Assuntos
Doenças Cardiovasculares , Diabetes Mellitus Tipo 2 , Doenças Cardiovasculares/complicações , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controle , Diabetes Mellitus Tipo 2/complicações , Peptídeo 1 Semelhante ao Glucagon , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Hemoglobinas Glicadas , Humanos , Hipoglicemiantes , Análise de Regressão , Redução de PesoRESUMO
Glucagon-like peptide-1 (GLP-1) is an incretin secreted from enteroendocrine preproglucagon (PPG)-expressing cells (traditionally known as L cells) in response to luminal nutrients that potentiates insulin secretion. Augmentation of endogenous GLP-1 secretion might well represent a novel therapeutic target for diabetes treatment in addition to the incretin-associated drugs currently in use. In this study, we found that PPG cells substantially express carbonic anhydrase 8 (CAR8), which has been reported to inhibit inositol 1,4,5-trisphosphate (IP3) binding to the IP3 receptor and subsequent Ca2+ efflux from the endoplasmic reticulum in neuronal cells. In vitro experiments using STC-1 cells demonstrated that Car8 knockdown increases long-chain fatty acid (LCFA)-stimulated GLP-1 secretion. This effect was reduced in the presence of phospholipase C (PLC) inhibitor; in addition, Car8 knockdown increased the intracellular Ca2+ elevation caused by α-linolenic acid, indicating that CAR8 exerts its effect on GLP-1 secretion via the PLC/IP3/Ca2+ pathway. Car8wdl null mutant mice showed significant increase in GLP-1 response to oral corn oil administration compared with that in wild-type littermates, with no significant change in intestinal GLP-1 content. These results demonstrate that CAR8 negatively regulates GLP-1 secretion from PPG cells in response to LCFAs, suggesting the possibility of augmentation of postprandial GLP-1 secretion by CAR8 inhibition.NEW & NOTEWORTHY This study focused on the physiological significance of carbonic anhydrase 8 (CAR8) in GLP-1 secretion from enteroendocrine preproglucagon (PPG)-expressing cells. We found an inhibitory role of CAR8 in LCFA-induced GLP-1 secretion in vitro and in vivo, suggesting a novel therapeutic approach to diabetes and obesity through augmentation of postprandial GLP-1 secretion by CAR8 inhibition.
Assuntos
Biomarcadores Tumorais/metabolismo , Óleo de Milho/farmacologia , Células Enteroendócrinas/efeitos dos fármacos , Ácidos Graxos/farmacologia , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Biomarcadores Tumorais/genética , Sinalização do Cálcio , Linhagem Celular , Células Enteroendócrinas/enzimologia , Glucagon/genética , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Proteínas do Tecido Nervoso/genética , Via Secretória , Fosfolipases Tipo C/metabolismoRESUMO
Our previous study demonstrated that sphingosine kinase 1-interacting protein (SKIP, or Sphkap) is expressed in pancreatic ß-cells, and depletion of SKIP enhances glucose-stimulated insulin secretion. We find here that SKIP is also expressed in intestinal K- and L-cells and that secretion of gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) as well as insulin are significantly increased, and blood glucose levels are decreased in SKIP-deficient (SKIP-/-) mice compared with those in wild-type mice. Plasma triglyceride (Tg), LDL cholesterol, and mRNA levels of proinflammatory cytokines in adipose tissues, livers, and intestines were found to be significantly decreased in SKIP-/- mice. The phenotypic characteristics of SKIP-/- mice, including adiposity and attenuation of basal inflammation, were abolished by genetic depletion of GIP. The improvement of glucose tolerance and lipid profiles in SKIP-/- mice were cancelled by GLP-1 receptor antagonist exendin-(9-39) treatment. In summary, depletion of SKIP ameliorates glucose tolerance by enhancing secretion of insulin and incretins, improves lipid metabolism, and reduces basal inflammation levels. Thus, inhibition of SKIP action may emerge as a new option for treatment of type 2 diabetes mellitus with metabolic dysfunction.-Liu, Y., Harashima, S., Wang, Y., Suzuki, K., Tokumoto, S., Usui, R., Tatsuoka, H., Tanaka, D., Yabe, D., Harada, N., Hayashi, Y., Inagaki, N. Sphingosine kinase 1-interacting protein is a dual regulator of insulin and incretin secretion.
Assuntos
Glicemia/metabolismo , Incretinas/metabolismo , Secreção de Insulina , Monoéster Fosfórico Hidrolases/metabolismo , Tecido Adiposo/metabolismo , Animais , Colesterol/sangue , Citocinas/genética , Citocinas/metabolismo , Feminino , Polipeptídeo Inibidor Gástrico/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Insulina/metabolismo , Mucosa Intestinal/citologia , Mucosa Intestinal/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Monoéster Fosfórico Hidrolases/genéticaRESUMO
Gastric inhibitory polypeptide (GIP) is an incretin secreted from enteroendocrine K cells and potentiates insulin secretion from pancreatic ß-cells. GIP also enhances long-chain triglyceride (LCT) diet-induced obesity and insulin resistance. Long-term intake of medium-chain triglyceride (MCT) diet is known to induce less body weight and fat mass gain than that of LCT diet. However, the effect of MCT diet feeding on GIP secretion and the effect of GIP on body weight and fat mass under MCT diet-feeding condition are unknown. In this study, we evaluated the effect of single MCT oil administration on GIP secretion and compared the effect of long-term MCT and LCT diet on body weight and fat mass gain in wild-type (WT) and GIP-knockout (GIP KO) mice. Single administration of LCT oil induced GIP secretion but that of MCT oil did not in WT mice. Long-term intake of LCT diet induced GIP hypersecretion and significant body weight and fat mass gain compared with that of control fat (CF) diet in WT mice. In contrast, MCT diet did not induce GIP hypersecretion, and MCT diet-fed mice showed smaller increase in body weight and fat mass gain compared with CF diet-fed mice. In GIP KO mice, body weight and fat mass were markedly attenuated in LCT diet-fed mice but not in MCT diet-fed mice. Our results suggest that long-term intake of MCT diet stimulates less GIP secretion and suppresses body weight and fat mass gain compared with that of LCT diet.
Assuntos
Tecido Adiposo/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Gorduras na Dieta/farmacologia , Polipeptídeo Inibidor Gástrico/metabolismo , Triglicerídeos/farmacologia , Tecido Adiposo/metabolismo , Adiposidade/efeitos dos fármacos , Animais , Peso Corporal/genética , Dieta , Gorduras na Dieta/classificação , Polipeptídeo Inibidor Gástrico/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Triglicerídeos/química , Aumento de Peso/efeitos dos fármacosRESUMO
Both high-fat (HFD) and high-carbohydrate (ST) diets are known to induce weight gain. Glucose-dependent insulinotropic polypeptide (GIP) is secreted mainly from intestinal K cells upon stimuli by nutrients such as fat and glucose, and it potentiates glucose-induced insulin secretion. GIP is well known to contribute to HFD-induced obesity. In this study, we analyzed the effect of ST feeding on GIP secretion and metabolic parameters to explore the role of GIP in ST-induced weight gain. Both wild-type (WT) and GIP receptor deficient ( GiprKO) mice were fed normal chow (NC), ST, or moderate (m)HFD for 22 wk. Body weight was measured, and then glucose tolerance tests were performed. Insulin secretion from isolated islets also was analyzed. WT mice fed ST or mHFD displayed weight gain concomitant with increased plasma GIP levels compared with WT mice fed NC. WT mice fed mHFD showed improved glucose tolerance due to enhanced insulin secretion during oral glucose tolerance tests compared with WT mice fed NC or ST. GiprKO mice fed mHFD did not display weight gain. On the other hand, GiprKO mice fed ST showed weight gain and did not display obvious glucose intolerance. Glucose-induced insulin secretion was enhanced during intraperitoneal glucose tolerance tests and from isolated islets in both WT and GiprKO mice fed ST compared with those fed NC. In conclusion, enhanced GIP secretion induced by mHFD-feeding contributes to increased insulin secretion and body weight gain, whereas GIP is marginally involved in weight gain induced by ST-feeding.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Gorduras na Dieta/farmacologia , Polipeptídeo Inibidor Gástrico/fisiologia , Aumento de Peso/efeitos dos fármacos , Animais , Carboidratos da Dieta/efeitos adversos , Glucose/metabolismo , Intolerância à Glucose/genética , Intolerância à Glucose/metabolismo , Teste de Tolerância a Glucose/métodos , Insulina/metabolismo , Resistência à Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores dos Hormônios Gastrointestinais/genética , Receptores dos Hormônios Gastrointestinais/metabolismoRESUMO
Fat accumulation with aging is a serious problem; glucose-dependent insulinotropic polypeptide/gastric inhibitory polypeptide (GIP) is an incretin that plays an important role in fat accumulation. GIP receptor knockout mice show reduced fat mass and improved insulin sensitivity associated with aging. Therefore, GIP is involved in fat accumulation and insulin resistance with aging. However, age-related changes of GIP secretion remain unclear. The present study aimed to elucidate age-related changes of GIP secretion and enteroendocrine K cells using GIP reporter [GIP-green fluorescent protein (GFP) knock-in heterozygous (GIPgfp/+)] mice. Aged 1-yr-old GIPgfp/+ mice exhibited a phenotype of fat accumulation, insulin resistance, and GIP hypersecretion compared with young (3-4 mo old) GIPgfp/+ mice. In aged mice, K-cell number in the small intestine and the mRNA expression levels of GIP and transcriptional factor pancreatic and duodenal homeobox-1 (Pdx1) in K cells were increased. K-cell number, GIP mRNA expression and content in small intestine, and GIP secretion were decreased after posteriori suppression of Pdx1 using intestine-specific gene transfer. Thus, Pdx1 positively regulates GIP mRNA and K-cell number in small intestine. Increased Pdx1 expression might be involved in GIP hypersecretion with aging. NEW & NOTEWORTHY Age-related changes of glucose-dependent insulinotropic polypeptide/gastric inhibitory polypeptide (GIP) secretion and K cells were investigated. We found that K-cell number and GIP and pancreatic and duodenal homeobox-1 (Pdx1) expression in K cells were increased in aged mice, which showed greater GIP secretion compared with young mice. In addition, we have succeeded in posteriori suppression of Pdx1 in small intestine using the method of intestine-specific gene transfer, and showed that K-cell number, GIP expression, and GIP secretion were decreased in the Pdx1-knockdown intestine.
Assuntos
Envelhecimento/fisiologia , Polipeptídeo Inibidor Gástrico , Proteínas de Homeodomínio , Receptores dos Hormônios Gastrointestinais , Transativadores , Tecido Adiposo/metabolismo , Animais , Células Enteroendócrinas , Polipeptídeo Inibidor Gástrico/genética , Polipeptídeo Inibidor Gástrico/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Insulina/metabolismo , Resistência à Insulina , Intestino Delgado/metabolismo , Camundongos , Camundongos Knockout , Receptores dos Hormônios Gastrointestinais/genética , Receptores dos Hormônios Gastrointestinais/metabolismo , Transativadores/genética , Transativadores/metabolismoRESUMO
AIMS/HYPOTHESIS: O-GlcNAcylation is characterised by the addition of N-acetylglucosamine to various proteins by O-GlcNAc transferase (OGT) and serves in sensing intracellular nutrients by modulating various cellular processes. Although it has been speculated that O-GlcNAcylation is associated with glucose metabolism, its exact role in whole body glucose metabolism has not been fully elucidated. Here, we investigated whether loss of O-GlcNAcylation globally and in specific organs affected glucose metabolism in mammals under physiological conditions. METHODS: Tamoxifen-inducible global Ogt-knockout (Ogt-KO) mice were generated by crossbreeding Ogt-flox mice with R26-Cre-ERT2 mice. Liver, skeletal muscle, adipose tissue and pancreatic beta cell-specific Ogt-KO mice were generated by crossbreeding Ogt-flox mice with Alb-Cre, Mlc1f-Cre, Adipoq-Cre and Pdx1 PB-CreER™ mice, respectively. Glucose metabolism was evaluated by i.p. glucose and insulin tolerance tests. RESULTS: Tamoxifen-inducible global Ogt-KO mice exhibited a lethal phenotype from 4 weeks post injection, suggesting that O-GlcNAcylation is essential for survival in adult mice. Tissue-specific Ogt deletion from insulin-sensitive organs, including liver, skeletal muscle and adipose tissue, had little impact on glucose metabolism under physiological conditions. However, pancreatic beta cell-specific Ogt-KO mice displayed transient hypoglycaemia (Ogt-flox 5.46 ± 0.41 vs Ogt-ßKO 3.88 ± 0.26 mmol/l) associated with about twofold higher insulin secretion and accelerated adiposity, followed by subsequent hyperglycaemia (Ogt-flox 6.34 ± 0.32 vs Ogt-ßKO 26.4 ± 2.37 mmol/l) with insulin depletion accompanied by beta cell apoptosis. CONCLUSIONS/INTERPRETATION: These findings suggest that O-GlcNAcylation has little effect on glucose metabolism in insulin-sensitive tissues but plays a crucial role in pancreatic beta cell function and survival under physiological conditions. Our results provide novel insight into O-GlcNAc biology and physiology in glucose metabolism.
Assuntos
Insulina/metabolismo , N-Acetilglucosaminiltransferases/metabolismo , Animais , Apoptose/fisiologia , Glucose/metabolismo , Resistência à Insulina/fisiologia , Células Secretoras de Insulina/metabolismo , Camundongos , Camundongos Knockout , Processamento de Proteína Pós-TraducionalRESUMO
Gastric inhibitory polypeptide (GIP) is an incretin released from enteroendocrine K cells in response to nutrient intake, especially fat. GIP is one of the contributing factors inducing fat accumulation that results in obesity. A recent study shows that fatty acid-binding protein 5 (FABP5) is expressed in murine K cells and is involved in fat-induced GIP secretion. We investigated the mechanism of fat-induced GIP secretion and the impact of FABP5-related GIP response on diet-induced obesity (DIO). Single oral administration of glucose and fat resulted in a 40% reduction of GIP response to fat but not to glucose in whole body FABP5-knockout (FABP5(-/-)) mice, with no change in K cell count or GIP content in K cells. In an ex vivo experiment using isolated upper small intestine, oleic acid induced only a slight increase in GIP release, which was markedly enhanced by coadministration of bile and oleic acid together with attenuated GIP response in the FABP5(-/-) sample. FABP5(-/-) mice exhibited a 24% reduction in body weight gain and body fat mass under a high-fat diet compared with wild-type (FABP5(+/+)) mice; the difference was not observed between GIP-GFP homozygous knock-in (GIP(gfp/gfp))-FABP5(+/+) mice and GIP(gfp/gfp)-FABP5(-/-) mice, in which GIP is genetically deleted. These results demonstrate that bile efficiently amplifies fat-induced GIP secretion and that FABP5 contributes to the development of DIO in a GIP-dependent manner.
Assuntos
Dieta Hiperlipídica , Gorduras na Dieta/farmacologia , Células Enteroendócrinas/efeitos dos fármacos , Células Enteroendócrinas/metabolismo , Proteínas de Ligação a Ácido Graxo/fisiologia , Polipeptídeo Inibidor Gástrico/metabolismo , Proteínas de Neoplasias/fisiologia , Obesidade/genética , Animais , Células Cultivadas , Dieta Hiperlipídica/efeitos adversos , Ingestão de Alimentos , Glucose/farmacologia , Camundongos , Camundongos Transgênicos , Obesidade/metabolismoRESUMO
Trelagliptin is the first once-weekly dipeptidyl peptidase-4(DPP-4) inhibitor in the world. Trelagliptin inhibits DPP-4 activity with lower drug concentration compared with other once- (or twice-) daily DPP-4 inhibitors in in vitro study. More than 70 % of DPP-4 activity is inhibited even 1 week after administration of trelagliptin administration in human study. 24-week trelagliptin monotherapy improved HbA1c(-0.33%) and fasting plasma glucose levels in Japanese patients with type 2 diabetes. Trelagliptin did not affect body weight and frequency of hypoglycemic events in this study. 52-week monotherapy and add-on therapy of trelagliptin also improved HbA1c levels without body weight gain and severe hypoglycemia. Therefore, trelagliptin has high efficacy and safety on glucose control in Japanese patients with type 2 diabetes.
Assuntos
Diabetes Mellitus/tratamento farmacológico , Dipeptidil Peptidase 4/metabolismo , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Ensaios Clínicos como Assunto , Inibidores da Dipeptidil Peptidase IV/administração & dosagem , Inibidores da Dipeptidil Peptidase IV/economia , Quimioterapia Combinada , Hemoglobinas Glicadas/análise , HumanosRESUMO
Gastric inhibitory polypeptide (GIP) is an incretin released from enteroendocrine K-cells in response to nutrient ingestion. GIP potentiates glucose-stimulated insulin secretion and induces energy accumulation into adipose tissue, resulting in obesity. Plasma GIP levels are reported to be increased in the obese state. However, the molecular mechanisms of GIP secretion and high fat diet (HFD)-induced GIP hypersecretion remain unclear, primarily due to difficulties in separating K-cells from other intestinal epithelial cells in vivo. In this study, GIP-GFP knock-in mice that enable us to visualize K-cells by enhanced GFP were established. Microarray analysis of isolated K-cells from these mice revealed that transcriptional regulatory factor X6 (Rfx6) is expressed exclusively in K-cells. In vitro experiments using the mouse intestinal cell line STC-1 showed that knockdown of Rfx6 decreased mRNA expression, cellular content, and secretion of GIP. Rfx6 bound to the region in the gip promoter that regulates gip promoter activity, and overexpression of Rfx6 increased GIP mRNA expression. HFD induced obesity and GIP hypersecretion in GIP-GFP heterozygous mice in vivo. Immunohistochemical and flow cytometry analysis showed no significant difference in K-cell number between control fat diet-fed (CFD) and HFD-fed mice. However, GIP content in the upper small intestine and GIP mRNA expression in K-cells were significantly increased in HFD-fed mice compared with those in CFD-fed mice. Furthermore, expression levels of Rfx6 mRNA were increased in K-cells of HFD-fed mice. These results suggest that Rfx6 increases GIP expression and content in K-cells and is involved in GIP hypersecretion in HFD-induced obesity.
Assuntos
Tecido Adiposo/metabolismo , Proteínas de Ligação a DNA/genética , Células Enteroendócrinas/metabolismo , Polipeptídeo Inibidor Gástrico/genética , Obesidade/genética , Fatores de Transcrição/genética , Tecido Adiposo/patologia , Animais , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/metabolismo , Dieta Hiperlipídica/efeitos adversos , Células Enteroendócrinas/patologia , Polipeptídeo Inibidor Gástrico/metabolismo , Expressão Gênica , Técnicas de Introdução de Genes , Genes Reporter , Glucose/metabolismo , Proteínas de Fluorescência Verde , Insulina/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Camundongos , Camundongos Transgênicos , Obesidade/etiologia , Obesidade/metabolismo , Obesidade/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Cultura Primária de Células , Regiões Promotoras Genéticas , Ligação Proteica , RNA Interferente Pequeno , Fatores de Transcrição de Fator Regulador X , Transdução de Sinais , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismoRESUMO
Wang et al. report that clinical dipeptidyl peptidase-4 (DPP-4) inhibitors show little effect on microbial DPP-4 produced by Bacteroides genus. Furthermore, oral administration of microbial DPP-4 to high-fat diet-fed mice was found to reduce plasma active glucagon-like peptide-1 levels through an increase in extraluminal intestinal tissular DPP-4 activity, resulting in reduced glucose-induced insulin levels and exacerbated glucose tolerance.
Assuntos
Dipeptidil Peptidase 4 , Inibidores da Dipeptidil Peptidase IV , Microbioma Gastrointestinal , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Inibidores da Dipeptidil Peptidase IV/farmacologia , Animais , Microbioma Gastrointestinal/efeitos dos fármacos , Humanos , Dipeptidil Peptidase 4/metabolismo , Camundongos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/microbiologia , Dieta HiperlipídicaRESUMO
Glycogen storage disease type 1a (GSD-1a) is a rare congenital disease. Recently, life expectancy with GSD-1a has been improved by its early diagnosis and management. Complications of diabetes with GSD-1a are extremely rare. The optimal treatment for glucose control using this disease combination remains unclear. The existence of GSD-1a and diabetes can cause both hypoglycemia and hyperglycemia, making glucose control especially problematic. In the present report, α-glucosidase inhibitor (α-GI) and dipeptidyl peptidase-4 (DPP-4) inhibitors improved hyperglycemia without symptoms of hypoglycemia in a patient with diabetes and GSD-1a using intermittent continuous glucose monitoring (isCGM).
Assuntos
Doença de Depósito de Glicogênio Tipo I , Inibidores de Glicosídeo Hidrolases , Humanos , Doença de Depósito de Glicogênio Tipo I/complicações , Doença de Depósito de Glicogênio Tipo I/diagnóstico , Inibidores de Glicosídeo Hidrolases/uso terapêutico , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Masculino , Glicemia/metabolismo , Feminino , Hipoglicemiantes/uso terapêutico , Adulto , Hiperglicemia/complicações , Hiperglicemia/diagnósticoRESUMO
Introduction: Incretin-based drugs are extensively utilized in the treatment of type 2 diabetes (T2D), with remarkable clinical efficacy. These drugs were developed based on findings that the incretin effect is reduced in T2D. The incretin effect in East Asians, whose pancreatic ß-cell function is more vulnerable than that in Caucasians, however, has not been fully examined. In this study, we investigated the effects of incretin in Japanese subjects. Methods: A total of 28 Japanese subjects (14 with normal glucose tolerance [NGT], 6 with impaired glucose tolerance, and 8 with T2D) were enrolled. Isoglycemic oral (75 g glucose tolerance test) and intravenous glucose were administered. The numerical incretin effect and gastrointestinally-mediated glucose disposal (GIGD) were calculated by measuring the plasma glucose and entero-pancreatic hormone concentrations. Results and discussion: The difference in the numerical incretin effect among the groups was relatively small. The numerical incretin effect significantly negatively correlated with the body mass index (BMI). GIGD was significantly lower in participants with T2D than in those with NGT, and significantly negatively correlated with the area under the curve (AUC)-glucose, BMI, and AUC-glucagon. Incretin concentrations did not differ significantly among the groups. We demonstrate that in Japanese subjects, obesity has a greater effect than glucose tolerance on the numerical incretin effect, whereas GIGD is diminished in individuals with both glucose intolerance and obesity. These findings indicate variances as well as commonalities between East Asians and Caucasians in the manifestation of incretin effects on pancreatic ß-cell function and the integrated capacity to handle glucose.
Assuntos
Glicemia , Diabetes Mellitus Tipo 2 , Intolerância à Glucose , Teste de Tolerância a Glucose , Incretinas , Obesidade , Humanos , Incretinas/sangue , Intolerância à Glucose/sangue , Masculino , Feminino , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/epidemiologia , Obesidade/sangue , Pessoa de Meia-Idade , Glicemia/metabolismo , Japão/epidemiologia , Adulto , Idoso , Povo Asiático , Índice de Massa Corporal , População do Leste AsiáticoRESUMO
The Japan Diabetes Society (JDS) adopted a sweeping decision to release consensus statements on relevant issues in diabetes management that require updating from time to time and launched a "JDS Committee on Consensus Statement Development." In March 2020, the committee's first consensus statement on "Medical Nutrition Therapy and Dietary Counseling for People with Diabetes" was published. In September 2022, a second consensus "algorithm for pharmacotherapy in people with type 2 diabetes" was proposed. In developing an algorithm for diabetes pharmacotherapy in people with type 2 diabetes, the working concept was that priority should be given to selecting such medications as would appropriately address the diabetes pathology in each patient while simultaneously weighing the available evidence for these medications and the prescribing patterns in clinical practice in Japan. These consensus statements are intended to present the committee's take on diabetes management in Japan, based on the evidence currently available for each of the issues addressed. It is thus hoped that practicing diabetologists will not fail to consult these statements to provide the best available practice in their respective clinical settings. Given that the persistent dual GIP/GLP-1 receptor agonist tirzepatide was approved in April 2023, these consensus statements have been revised1). In this revision, specifically, tirzepatide was added to the end of [likely involving insulin resistance] of "Obese patients" in Step 1: "Select medications to address the diabetes pathology involved" in Fig. 2. While the sentence, "Insulin insufficiency and resistance can be assessed by referring to the various indices listed in the JDS 'Guide to Diabetes Management.' was mentioned in the previous edition as well, "While insulin resistance is analogized based on BMI, abdominal obesity, and visceral fat accumulation, an assessment of indicators (e.g., HOMA-IR) is desirable" was added as information in order to more accurately recognize the pathology. Regarding Step 2: "Give due consideration to safety," "For renal excretion" was added to the "Rule of thumb 2: Avoid glinides in patients with renal impairment." The order of the medications in "rule of thumb 3: Avoid thiazolidinediones and biguanides in patients with heart failure (in whom they are contraindicated)." to thiazolidinediones then biguanides. In the description of the lowest part of Fig. 2, for each patient failing to achieve his/her HbA1c control goal, "while reverting to step 1" was changed to "while reverting to the opening" and "including reassessment if the patient is indicated for insulin therapy" was added. In the separate table, the column for tirzepatides was added, while the two items, "Characteristic side effects" and "Persistence of effect" were added to the area of interest. The revision also carried additional descriptions of the figure and table such as tirzepatides and "Characteristic side effects" in the statement, and while not mentioned in the proposed algorithm figure, nonalcoholic fatty liver disease (NAFLD) is covered from this revision for patients with comorbidities calling for medical attention. Moreover, detailed information was added to the relative/absolute indication for insulin therapy, the Kumamoto Declaration 2013 for glycemic targets, and glycemic targets for older people with diabetes. Again, in this revision, it is hoped that the algorithm presented here will not only contribute to improved diabetes management in Japan, but will continue to evolve into a better algorithm over time, reflecting new evidence as it becomes available.
RESUMO
This algorithm was issued for the appropriate use of drugs for the treatment of type 2 diabetes mellitus in Japan. The revisions include safety considerations, fatty liver disease as a comorbidity to be taken into account and the position of tirzepatide.