OBJECTIVE: To elucidate the effect of Huanglian-Renshen-Decoction (HRD) on ameliorating type 2 diabetes mellitus by maintaining islet β -cell identity through regulating paracrine and endocrine glucagon-like peptide-1 (GLP-1)/GLP-1 receptor (GLP-1R) in both islet and intestine. METHODS: The db/db mice were divided into the model (distilled water), low-dose HRD (LHRD, 3 g/kg), high-dose HRD (HHRD, 6 g/kg), and liraglutide (400 µ g/kg) groups using a random number table, 8 mice in each group. The db/m mice were used as the control group (n=8, distilled water). The entire treatment of mice lasted for 6 weeks. Blood insulin, glucose, and GLP-1 levels were quantified using enzyme-linked immunosorbent assay kits. The proliferation and apoptosis factors of islet cells were determined by immunohistochemistry (IHC) and immunofluorescence (IF) staining. Then, GLP-1, GLP-1R, prohormone convertase 1/3 (PC1/3), PC2, v-maf musculoaponeurotic fibrosarcoma oncogene homologue A (MafA), and pancreatic and duodenal homeobox 1 (PDX1) were detected by Western blot, IHC, IF, and real-time quantitative polymerase chain reaction, respectively. RESULTS: HRD reduced the weight and blood glucose of the db/db mice, and improved insulin sensitivity at the same time (P<0.05 or P<0.01). HRD also promoted mice to secrete more insulin and less glucagon (P<0.05 or P<0.01). Moreover, it also increased the number of islet β cell and decreased islet α cell mass (P<0.01). After HRD treatment, the levels of GLP-1, GLP-1R, PC1/3, PC2, MafA, and PDX1 in the pancreas and intestine significantly increased (P<0.05 or P<0.01). CONCLUSION HRD can maintain the normal function and identity of islet β cell, and the underlying mechanism is related to promoting the paracrine and endocrine activation of GLP-1 in pancreas and intestine.
Animals ; Glucagon-Like Peptide 1/metabolism* ; Diabetes Mellitus, Type 2/metabolism* ; Glucagon-Like Peptide-1 Receptor/metabolism* ; Insulin-Secreting Cells/pathology* ; Drugs, Chinese Herbal/pharmacology* ; Male ; Blood Glucose/metabolism* ; Insulin/blood* ; Mice ; Intestinal Mucosa/pathology* ; Apoptosis/drug effects* ; Cell Proliferation/drug effects* ; Islets of Langerhans/pathology*

This study aims to observe the effects of different doses of Astragali Radix on the expression of glucagon(GLP-1) in se-rum and glucagon receptor(GLP-1R) in cartilage tissue in rats with knee osteoarthritis(KOA), explore the effect of Astragali Radix on the inflammation and apoptosis of KOA by regulating GLP-1/GLP-1R signaling axis, and investigate the mechanism of its action in alleviating KOA. Forty-eight male SD rats were randomly divided into six groups: blank group, model group, low-, medium-, and high-dose Astragali Radix groups(3.125, 6.25, and 12.5 g·kg~(-1)), and glucosamine sulfate group(0.1 g·kg~(-1)). Except for the blank group, rats in other groups were injected with sodium iodoacetate(MIA) into the knee joint to establish KOA models. After successful modeling, the rats were continuously treated for five weeks. Enzyme-linked immunosorbent assay(ELISA) was used to detect the levels of GLP-1, tumor necrosis factor-alpha(TNF-α), and interleukin-1β(IL-1β) in rat serum. Pathological examination was utilized to observe the pathological changes in knee joint cartilage. The mRNA levels of TNF-α and MMP13 in knee joint cartilage were detected by qRT-PCR, and the protein expression levels of GLP-1R, MMP13, and caspase-8 in knee joint cartilage were detected by Western blot. The expression of GLP-1R and MMP13 in the knee joint was detected by immunohistochemistry. Tunel staining was used to observe the apoptosis of chondrocytes in the knee joint. The above experimental results showed that Astragali Radix may raise the serum levels of GLP-1, reduce serum levels of TNF-α and IL-1, and decrease the relative mRNA expression of TNF-α and MMP13 through the GLP-1/GLP-1R axis. It thus activated GLP-1R, reduced the protein expression of MMP13 and caspase-8 in cartilage, and regulated their related signaling pathways to improve inflammation and apoptosis, so as to protect cartilage and improve KOA.
Animals ; Male ; Rats, Sprague-Dawley ; Osteoarthritis, Knee/genetics* ; Rats ; Drugs, Chinese Herbal/pharmacology* ; Glucagon-Like Peptide 1/metabolism* ; Glucagon-Like Peptide-1 Receptor/metabolism* ; Astragalus propinquus/chemistry* ; Humans ; Matrix Metalloproteinase 13/metabolism* ; Signal Transduction/drug effects* ; Tumor Necrosis Factor-alpha/metabolism* ; Astragalus Plant/chemistry* ; Apoptosis/drug effects*

Humans ; Glucagon-Like Peptide-1 Receptor/agonists* ; Diabetic Cardiomyopathies/drug therapy* ; Diabetes Mellitus, Type 2

Obesity is an important risk factor of type 2 diabetes (T2D), which has become an important factor threatening human health. However, no perfect drug choice for obesity exists. Semaglutide is a kind of human glucagon-like peptide-1 (GLP-1) analog that promotes insulin secretion while inhibiting glucagon secretion through a glucose concentration-dependent mechanism. GLP-1 can also delay stomach emptying and suppress appetite to help lose weight. This review summarizes clinical evidence of the semaglutide effect on T2D and obesity and establishes expectations on future clinical trials for obesity treatment.
Diabetes Mellitus, Type 2/drug therapy* ; Glucagon-Like Peptide-1 Receptor/therapeutic use* ; Glucagon-Like Peptides ; Humans ; Hypoglycemic Agents/therapeutic use* ; Motivation ; Obesity/drug therapy*

The Korean Ministry of Food and Drug Safety has approved three anti-obesity drugs for long-term management in the past decade. In addition, since 2019, bariatric surgery has been financially supported by National Health Insurance Service in Korea. In this review, the mechanisms of action and the clinical implications of the recently approved anti-obesity drugs, lorcaserin, naltrexone/bupropion, and liraglutide are explained. Lorcaserin stimulates proopiomelanocortin (POMC)/cocaine- and amphetamine-regulated transcript (CART) neurons and inhibits neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons, which results in the activation of melanocortin 3/4 receptors. Naltrexone/bupropion stimulates POMC neurons through bupropion; this stimulation is augmented by blocking the autoinhibitory mechanism of POMC with naltrexone. The hypophagic effect of liraglutide is mediated through the direct activation of POMC/CART neurons and the indirect suppression of NPY/AgRP neurons through γ-aminobutyric acid-dependent signaling, with adjunctive suppression of the mesolimbic dopamine reward system. In addition to liraglutide, another glucagon-like peptide-1 receptor agonist, semaglutide, is expected to be added to the list of anti-obesity drugs in the near future. In patients with obesity and high cardiovascular risk, lorcaserin was considered neutral and liraglutide was considered favorable, whereas inconclusive results were obtained for naltrexone/bupropion.
Anti-Obesity Agents ; Bariatric Surgery ; Bupropion ; Dopamine ; Glucagon-Like Peptide-1 Receptor ; Humans ; Korea ; Liraglutide ; Naltrexone ; National Health Programs ; Neurons ; Neuropeptide Y ; Obesity ; Pro-Opiomelanocortin ; Reward

Glucagon-like peptide-1 (GLP-1) expression is shared by both intestinal cells and neurons of brainstem, which plays anorexigenic role on food intake. However, the exact source of physiological GLP-1 influencing food intake and pertinent mechanism of GLP-1 receptor agonists (GLP-1RA) remain unelucidated. In this study, the immediate early gene product c-Fos was chosen as the specific antigen for immunohistochemistry to show the certain areas of central nervous system (CNS) activation by the GLP-1RA. Thirty normal SD rats were randomly assigned to 3 groups, which were single intraperitoneally injected with Liraglutide (200 μg/kg), Exenatide (10 μg/kg) and saline, respectively. After injection, the amount of food intake and acute glycemic variation were assessed for comparison. The results showed that acute pharmacological dosage of GLP-1RA (Liraglutide or Exenatide) could significantly influence food intake. However, glycemic change indicated that the anorexic effect was dissociated with change in blood glucose in normal rats. Moreover, c-Fos was expressed significantly higher in major critical nuclei related to food intake in GLP-1RA groups when compared with the control group, and its expression was also found in spinal cord. The results suggested that acute administration of pharmacological doses of GLP-1 influences CNS via circulation and vagal pathways, especially on the arcuate nucleus (ARC) and the nucleus of solitary tract (NTS), and GLP-1 modulates autonomic nervous activities.
Animals ; Eating ; drug effects ; Exenatide ; pharmacology ; Glucagon-Like Peptide-1 Receptor ; agonists ; Liraglutide ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley

Weight loss is an important goal in the management of several chronic conditions, including type 2 diabetes mellitus, and pharmacological therapies that aid weight loss are appealing. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2is) are novel glucose-lowering therapies that have been shown to induce clinically significant reductions in body weight. However, this weight loss may not be attributed solely to fat mass (FM). Given the importance of skeletal muscle and lean body mass (LBM) on cardio-metabolic health and physical function, we reviewed the available literature reporting the effects of GLP-1RAs and SGLT2is on body composition. Results demonstrate that, in most circumstances, the weight loss associated with both therapies predominantly comprises a reduction in FM, although significant heterogeneity exists between studies. In over half of the studies identified, the proportion of LBM reduction ranged between 20% and 50% of total weight lost, which is consistent with diet-induced weight loss and bariatric surgery. No clear differences existed between GLP-1RAs and SGLT2is. Consequently, the loss of LBM and skeletal muscle associated with weight loss induced by GLP-1RAs and SGLT2is warrants attention. Strategies to preserve skeletal muscle and improve physical function, for example through structured exercise, are of great importance.
Bariatric Surgery ; Body Composition ; Body Weight ; Diabetes Mellitus, Type 2 ; Glucagon-Like Peptide 1 ; Glucagon-Like Peptide-1 Receptor ; Humans ; Muscle, Skeletal ; Population Characteristics ; Weight Loss

OBJECTIVE: To study the effect of exendin-4(Ex-4) on the differentiation of neural stem cells(NSCs) in adult mouse subventricular zone(SVZ)and its mechanism . METHODS: NSCs in the SVZ were derived from 5-week C57BL/6J mice and the expression of nestin was detected by immunofluorescence. The cell morphology was observed after the cells treatmed with 100 nmol/L Ex-4 for 14 days.The expressions of nestin and glucagon-like peptide-1 receptor (GLP-1R) were detected by immunofluorescence. GLP-1R was knocked down by using shRNA and the study was divided into four groups: control group, Ex-4 group, GLP-1R knockdown group, GLP-1R knockdown + Ex-4 group. After treatment with 100 nmol/L Ex-4 for 14 d, β-tublin III and glial fibrillary acidic protein (GFAP) were labeled by immunofluorescence and then the proportion of β-tublin III positive cells were counted. Western blot was used to detect the activation of cAMP-response element binding protein (CREB) in NSCs. In order to further study the effects of Ex-4 on mitogen-activated protein kinase(MAPK) and phosphatidylinositol 3-hydroxy kinase (PI3K) pathways, the cells were pretreated with MAPK inhibitor U0126 at a concentration of 0.07 μmol/L for 30 min or PI3K inhibitor LY294002 at 50 μmol for 2 h, respectively. The study was divided into six groups: control group, Ex-4 group, U0126 group, U0126 + Ex-4 group, LY294002 group, LY294002 + Ex-4 group. The activation of CREB in each group was detected by Western blot. The experiment was repeated three times independently. RESULTS: NSCs were successfully extracted from SVZ of C57BL/6J mice. Immunofluorescence showed that nestin and GLP-1R were positive in NSCs. Compared with the control group, the proportion of neurons differentiated from Ex-4 group was higher. The percentage of neurons in GLP-1R knockdown + Ex-4 group was basically the same as that in control group (P＜0.01). The positive cells of beta-tublin III showed positive activation of GLP-1R and CREB. Western blot showed that CREB was significantly activated in the Ex-4 group, and knockdown of GLP-1R abolished its activation (P＜0.01). U0126 did not affect Ex-4-mediated CERB activation, and LY294002 significantly reduced Ex-4-mediated CREB activation (P＜0.01). CONCLUSION Ex-4 promotes the differentiation of NSCs into neurons in SVZ of adult mice through GLP-1R receptor, which may be achieved through PI3K/CREB pathway.
Animals ; Cell Differentiation ; Cells, Cultured ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Exenatide ; pharmacology ; Gene Knockdown Techniques ; Glucagon-Like Peptide-1 Receptor ; genetics ; metabolism ; Lateral Ventricles ; cytology ; Mice ; Mice, Inbred C57BL ; Neural Stem Cells ; cytology ; Phosphatidylinositol 3-Kinases

In 2018, the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) published a consensus recommendation on management of hyperglycemia. This consensus report emphasized the need for patient-centered management considering multimorbidity and individual patient preferences and barriers. Patients with type 2 diabetes with established atherosclerotic cardiovascular disease who fail to control blood glucose with the initial glucose-lowering medication are recommended a sodium-glucose cotransporter 2 (SGLT2) inhibitor or a glucagon-like peptide 1 (GLP-1) receptor agonist. For patients with chronic kidney disease and heart failure, SGLT2 inhibitors are recommended. In patients who need an injectable medication, GLP-1 receptor agonists are the preferred choice over insulin. In this section, we summarize “Management of Hyperglycemia in Type 2 Diabetes, 2018. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD).”
Atherosclerosis ; Blood Glucose ; Cardiovascular Diseases ; Comorbidity ; Consensus ; Diabetes Mellitus ; Glucagon-Like Peptide 1 ; Glucagon-Like Peptide-1 Receptor ; Heart Failure ; Humans ; Hyperglycemia ; Insulin ; Patient Preference ; Patient-Centered Care ; Renal Insufficiency, Chronic

According to the American Diabetes Association (ADA) and the European Association for the Study of Diabetes guideline for treatment of diabetes, glucagon-like peptide-1 receptor agonist (GLP-1 RA) is recommended in diabetic patients with established atherosclerotic cardiovascular disease. This recommendation is based on the results of recent cardiovascular outcome trials of this kind of medications. GLP-1 RAs have a glucose lowering effect with weight loss and a lower incidence of hypoglycemia, and can improve cardiovascular outcomes such as three-point major cardiovascular events composed of death from cardiovascular causes, non-fatal myocardial infarction, and non-fatal stroke. Also, several GLP-1 RAs have beneficial effects on renal outcomes, mainly due to improvement in macroalbuminuria. In addition, high-dose liraglutide (3 mg/day subcutaneous injection) showed efficacy for reducing body weight. Therefore GLP-1 RA may be effective in patients with established cardiovascular disease, chronic kidney disease, and/or metabolic syndrome.
Body Weight ; Cardiovascular Diseases ; Diabetes Mellitus ; Glucagon-Like Peptide 1 ; Glucagon-Like Peptide-1 Receptor ; Glucose ; Humans ; Hypoglycemia ; Incidence ; Kidney Diseases ; Liraglutide ; Myocardial Infarction ; Obesity ; Renal Insufficiency, Chronic ; Stroke ; Weight Loss