Glucagon-like Peptide-1 Levels Research Articles

Electroacupuncture improves obesity and promotes white adipose tissue browning by regulating central glucagon-like peptide-1

To observe the effect of electroacupuncture （EA） on white adipose tissue （WAT） browning by regulating central glucagon-like peptide-1 （GLP-1）, so as to explore the possible central mechanisms of EA in improving obesity. Thirty male Wistar rats were randomly divided into normal group, model group, EA group, HM3D group, and EA+HM4D group, with 6 rats in each group. The obesity rat model was obtained by feeding with high-fat diet for 8 weeks. Adeno-associated virus combined with DREADDs was injected into bilateral nucleus of solitary tract （NTS）, with rAAV-GLP-1+rAAV-4D applied to the EA+HM4D group, rAAV-GLP-1+rAAV-3D applied to the HM3D group, and rAAV-GLP-1+rAAV-GFP applied to other 3 groups. After modeling, rats in the EA and EA+HM4D groups received EA treatment at bilateral "Zusanli"（ST36）, "Fenglong"（ST40）, "Guanyuan"（CV4） and "Zhongwan"（CV12）, with successive waves （2 Hz, 1 mA） for 10 minutes, 3 times a week, for a total of 8 weeks. Body mass of rats in each group were measured before and 2, 4, 6, and 8 weeks after intervention. Abdominal and perirenal WAT mass was weighed, serum triglyceride （TG） and total cholesterol （TC） contents were detected by using automatic analyzer, and nonestesterified fatty acid （NEFA） content was detected by using colorimetric assay kit. The morphology of abdominal WAT lipid droplets was observed by HE staining. The mRNA expressions of GLP-1 in NTS, AMPK in ventromedial nucleus of hypothalamus（VMH）, UCP1 and PGC-1α in subcutaneous fat were detected by real-time PCR. The protein expression levels of GLP-1, AMPK, phosphorylated-AMPK, UCP1 and PGC-1α were detected by Western blot. The activation level of GLP-1 neurons in NTS was observed by immunofluorescence. Compared with the normal group, abdominal WAT lipid droplets were enlarged, body weight, serum TG, TC, NEFA contents, abdominal and perirenal WAT mass, mRNA and protein expression levels of AMPK were significantly increased（P<0.01, P<0.05）, while GLP-1 neurons activation level, mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α, and AMPK protein phosphorylation were decreased （P<0.01） in the model group. After EA intervention, body weight at 6 and 8 weeks after intervention and other indexes mentioned above were all significantly reversed （P<0.01, P<0.05） in the EA group in comparison with those of the model group. Compared with the EA group, the HM3D group had reduced abdominal WAT lipid droplets size, decreased serum TG, TC, and NEFA contents, and protein expression level of AMPK（P<0.01, P<0.05）, with increased mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α, and phosphorylation level of AMPK protein（P<0.01, P<0.05）, while the EA+HM4D group had enlarged abdominal WAT lipid droplets, increased body weight 6 and 8 weeks after intervention, abdominal and renal WAT mass, and NEFA content （P<0.01, P<0.05）, with decreased serum TG content, activation level of GLP-1 neurons in the NTS, mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α （P<0.01, P<0.05）, as well as down-regulated phosphorylation of AMPK protein and mRNA （P<0.01, P<0.05）. EA can effectively promote the browning of WAT, which may be related to the activation of GLP-1 neurons in the NTS, as well as the promotion of the phosphorylation of AMPK in the VMH and up-regulation of UCP1.

Electroacupuncture improves obesity and promotes white adipose tissue browning by regulating central glucagon-like peptide-1

To observe the effect of electroacupuncture （EA） on white adipose tissue （WAT） browning by regulating central glucagon-like peptide-1 （GLP-1）, so as to explore the possible central mechanisms of EA in improving obesity. Thirty male Wistar rats were randomly divided into normal group, model group, EA group, HM3D group, and EA+HM4D group, with 6 rats in each group. The obesity rat model was obtained by feeding with high-fat diet for 8 weeks. Adeno-associated virus combined with DREADDs was injected into bilateral nucleus of solitary tract （NTS）, with rAAV-GLP-1+rAAV-4D applied to the EA+HM4D group, rAAV-GLP-1+rAAV-3D applied to the HM3D group, and rAAV-GLP-1+rAAV-GFP applied to other 3 groups. After modeling, rats in the EA and EA+HM4D groups received EA treatment at bilateral "Zusanli"（ST36）, "Fenglong"（ST40）, "Guanyuan"（CV4） and "Zhongwan"（CV12）, with successive waves （2 Hz, 1 mA） for 10 minutes, 3 times a week, for a total of 8 weeks. Body mass of rats in each group were measured before and 2, 4, 6, and 8 weeks after intervention. Abdominal and perirenal WAT mass was weighed, serum triglyceride （TG） and total cholesterol （TC） contents were detected by using automatic analyzer, and nonestesterified fatty acid （NEFA） content was detected by using colorimetric assay kit. The morphology of abdominal WAT lipid droplets was observed by HE staining. The mRNA expressions of GLP-1 in NTS, AMPK in ventromedial nucleus of hypothalamus（VMH）, UCP1 and PGC-1α in subcutaneous fat were detected by real-time PCR. The protein expression levels of GLP-1, AMPK, phosphorylated-AMPK, UCP1 and PGC-1α were detected by Western blot. The activation level of GLP-1 neurons in NTS was observed by immunofluorescence. Compared with the normal group, abdominal WAT lipid droplets were enlarged, body weight, serum TG, TC, NEFA contents, abdominal and perirenal WAT mass, mRNA and protein expression levels of AMPK were significantly increased（P<0.01, P<0.05）, while GLP-1 neurons activation level, mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α, and AMPK protein phosphorylation were decreased （P<0.01） in the model group. After EA intervention, body weight at 6 and 8 weeks after intervention and other indexes mentioned above were all significantly reversed （P<0.01, P<0.05） in the EA group in comparison with those of the model group. Compared with the EA group, the HM3D group had reduced abdominal WAT lipid droplets size, decreased serum TG, TC, and NEFA contents, and protein expression level of AMPK（P<0.01, P<0.05）, with increased mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α, and phosphorylation level of AMPK protein（P<0.01, P<0.05）, while the EA+HM4D group had enlarged abdominal WAT lipid droplets, increased body weight 6 and 8 weeks after intervention, abdominal and renal WAT mass, and NEFA content （P<0.01, P<0.05）, with decreased serum TG content, activation level of GLP-1 neurons in the NTS, mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α （P<0.01, P<0.05）, as well as down-regulated phosphorylation of AMPK protein and mRNA （P<0.01, P<0.05）. EA can effectively promote the browning of WAT, which may be related to the activation of GLP-1 neurons in the NTS, as well as the promotion of the phosphorylation of AMPK in the VMH and up-regulation of UCP1.

An Association between Decreased Small Intestinal RNA Modification and Disturbed Glucagon-like Peptide-1 Secretion under High-Fat Diet Stress.

Unhealthy diets rich in fats and/or sugar are considered as the major external cause of the obesity epidemic, which is often accompanied by a significant decrease in gut hormone glucagon-like peptide-1 (GLP1) levels. Numerous studies have demonstrated notable contributions of the gut microbiota in this process. Nevertheless, the underlying mechanism still needs further investigation. The role of epigenetic modifications in gene expression and metabolism has been well demonstrated, with m6A methylation on RNAs being the most prevalent modification throughout their metabolism. In the present study, we found that the expressions of small intestinal Gcg and Pc3, two key genes regulating GLP1 expression, were significantly downregulated in obese mice, associated with reduced GLP1 level. Immunohistochemistry analysis indicated that a high-fat diet slightly increased the density of enteroendocrine L cells in the small intestine, implying that decreased GLP1 levels were not caused by the changes in L cell intensity. Instead, the small intestinal m6A level as well as the expression of known "writers", mettl3/14 and wtap, were found to be positively correlated with the expression of Gcg and Pc3. Fecal microbiota transplantation with feces from normal and obese mice daily to antibiotic-treated mice revealed that dysbiosis in diet-induced obesity was sufficient to reduce serum GLP1, small intestinal m6A level, and intestinal expressions of Gcg, Pc3, and writer genes (mettl3/14, wtap). However, as the most direct and universal methyl donor, the production of fecal S-adenosylmethionine was neither affected by the different dietary patterns nor their shaped microbiota. These results suggested that microbial modulation of the epitranscriptome may be involved in regulating GLP1 expression, and highlighted epitranscriptomic modifications as an additional level of interaction between diet and individual health.

Neprilysin deficiency reduces hepatic gluconeogenesis in high fat-fed mice

Neprilysin is a peptidase that cleaves glucoregulatory peptides, including glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK). Some studies suggest that its inhibition in diabetes and/or obesity improves glycemia, and that this is associated with enhanced insulin secretion, glucose tolerance and insulin sensitivity. Whether reduced neprilysin activity also improves hepatic glucose metabolism has not been explored. We sought to determine whether genetic deletion of neprilysin suppresses hepatic glucose production (HGP) in high fat-fed mice. Nep+/+ and Nep−/− mice were fed high fat diet for 16 weeks, and then underwent a pyruvate tolerance test (PTT) to assess hepatic gluconeogenesis. Since glycogen breakdown in liver can also yield glucose, we assessed liver glycogen content in fasted and fed mice. In Nep−/− mice, glucose excursion during the PTT was reduced when compared to Nep+/+ mice. Further, liver glycogen levels were significantly greater in fasted but not fed Nep−/− versus Nep+/+ mice. Since gut-derived factors modulate HGP, we tested whether gut-selective inhibition of neprilysin could recapitulate the suppression of hepatic gluconeogenesis observed with whole-body inhibition, and this was indeed the case. Finally, the gut-derived neprilysin substrates, GLP-1 and CCK, are well-known to suppress HGP. Having previously demonstrated elevated plasma GLP-1 levels in Nep−/− mice, we now measured plasma CCK bioactivity and reveal an increase in Nep−/− versus Nep+/+ mice, suggesting GLP-1 and/or CCK may play a role in reducing HGP under conditions of neprilysin deficiency. In sum, neprilysin modulates hepatic gluconeogenesis and strategies to inhibit its activity may reduce HGP in type 2 diabetes and obesity.

Cordyceps cicadae polysaccharides alleviate hyperglycemia by regulating gut microbiota and its mmetabolites in high-fat diet/streptozocin-induced diabetic mice.

The polysaccharides found in Cordyceps cicadae (C. cicadae) have received increasing academic attention owing to their wide variety of therapeutic activities. This study evaluated the hypoglycemic, antioxidant, and anti-inflammatory effects of polysaccharides from C. cicadae (CH-P). In addition, 16s rDNA sequencing and untargeted metabolomics analysis by liquid chromatography-mass spectrometry (LC-MS) were used to estimate the changes and regulatory relationships between gut microbiota and its metabolites. The fecal microbiota transplantation (FMT) was used to verify the therapeutic effects of microbial remodeling. The results showed that CH-P treatment displayed hypoglycemic, antioxidant, and anti-inflammatory effects and alleviated tissue damage induced by diabetes. The CH-P treatment significantly reduced the Firmicutes/Bacteroidetes ratio and increased the abundance of Bacteroides, Odoribacter, Alloprevotella, Parabacteroides, Mucispirillum, and significantly decreased the abundance of Helicobacter and Lactobacillus compared to the diabetic group. The alterations in the metabolic pathways were mostly related to amino acid biosynthesis and metabolic pathways (particularly those involving tryptophan) according to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Correlation analysis showed that Bacteroides, Odoribacter, Alloprevotella, Parabacteroides, and Mucispirillum were positively correlated with indole and its derivatives, such as 5-hydroxyindole-3-acetic acid. Indole intervention significantly improved hyperglycemic symptoms and insulin sensitivity, and increased the secretion of glucagon-like peptide-1 (GLP-1) in diabetic mice. FMT reduced blood glucose levels, improved glucose tolerance, and increased insulin sensitivity in diabetic mice. However, FMT did not significantly improve GLP-1 levels. This indicates that C. cicadae polysaccharides alleviate hyperglycemia by regulating the production of metabolites other than indole and its derivatives by gut microbiota. This study provides an important reference for the development of novel natural products.

Nutritive/non-nutritive sweeteners and high fat diet contribute to dysregulation of sweet taste receptors and metabolic derangements in oral, intestinal and central nervous tissues.

Overconsumption of non-nutritive sweeteners is associated with obesity, whereas the underlying mechanisms remain controversial. This study aimed to investigate the effects of long-term consumption of nutritive or non-nutritive sweeteners with or without high fat diet on sweet taste receptor expression in nutrient-sensing tissues and energy regulation dependent on sweet-sensing. 50 Male Sprague-Dawley rats (140-160g) were assigned to 10 groups (n = 5/group). All received fructose at 2.5% or 10%, sucralose at 0.01% or 0.015% or water with a normal chow diet or high fat diet for 12weeks. Food and drink intake were monitored daily. Oral glucose tolerance test and intraperitoneal glucose tolerance test were performed at week 10 and 11 respectively. Serum was obtained for measurement of biochemical parameters. Tongue, duodenum, jejunum, ileum, colon and hypothalamus were rapidly removed to assess gene expression. Long-term consumption of sweeteners impaired glucose tolerance, increased calorie intake and body weight. A significant upregulation of sweet taste receptor expression was observed in all the four intestinal segments in groups fed 0.01% sucralose or 0.015% sucralose, most strikingly in the ileum, accompanied by elevated serum glucagon-like peptide-1 levels and up-regulated expression of sodium-dependent glucose cotransporter 1 and glucose transporter 2. A significant down-regulation in the tongue and hypothalamus was observed in groups fed 10% fructose or 0.015% sucralose, with alterations in hypothalamic appetite signals. The presence of high fat diet differentially modulates sweet taste perception in nutrient-sensing tissues. Long-term consumption of whether nutritive sweeteners or non-nutritive sweeteners combined with high fat diet contribute to dysregulation of sweet taste receptor expression in oral, intestinal and central nervous tissues.

Safety and Efficacy of Liraglutide, 3.0 mg, Once Daily vs Placebo in Patients With Poor Weight Loss Following Metabolic Surgery

Metabolic surgery leads to weight loss and improved health, but these outcomes are highly variable. Poor weight loss is associated with lower circulating levels of glucagon-like peptide-1 (GLP-1). To assess the efficacy and safety of the GLP-1 receptor agonist, liraglutide, 3.0 mg, on percentage body weight reduction in patients with poor weight loss and suboptimal GLP-1 response after metabolic surgery. The Evaluation of Liraglutide 3.0 mg in Patients With Poor Weight Loss and a Suboptimal Glucagon-Like Peptide-1 Response (BARI-OPTIMISE) randomized placebo-controlled trial recruited adult patients at least 1 year after metabolic surgery who had experienced 20% or less body weight loss from the day of surgery and a suboptimal nutrient-stimulated GLP-1 response from 2 hospitals in London, United Kingdom, between October 2018 and November 2019. Key exclusion criteria were type 1 diabetes; severe concomitant psychiatric, gastrointestinal, cardiac, kidney or metabolic disease; and use of insulin, GLP-1 receptor analogues, and medication that can affect weight. The study period was 24 weeks followed by a 4-week follow-up period. Last participant follow-up was completed in June 2020. All participants and clinical study personnel were blinded to treatment allocation. Of 154 assessed for eligibility, 70 met trial criteria and were included in the study, and 57 completed follow-up. Liraglutide, 3.0 mg, once daily or placebo as an adjunct to lifestyle intervention with a 500-kcal daily energy deficit for 24 weeks, on a 1:1 allocation by computer-generated randomization sequence, stratified by surgery type (Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG]) and type 2 diabetes status. The primary outcome was change in percentage body weight from baseline to the end of the 24-week study period based on an intention-to-treat analysis. Participant safety was assessed through monitoring of biochemical parameters, including kidney and liver function, physical examination, and assessment for adverse events. A total of 70 participants (mean [SD] age, 47.6 [10.7] years; 52 [74%] female) with a poor weight loss response following RYGB or SG were randomized to receive 3.0-mg liraglutide (n = 35) or placebo (n = 35). All participants received at least 1 dose of the trial drug. Eight participants discontinued treatment (4 per group), and 2 in the 3.0-mg liraglutide group and 1 in the placebo group were lost to follow-up. Due to COVID-19 restrictions, 3 participants in the 3.0-mg liraglutide group and 7 in the placebo group were unable to attend their final in-person assessment. Estimated change in mean (SD) percentage body weight from baseline to week 24 was -8.82 (4.94) with liraglutide, 3.0 mg (n = 31), vs -0.54 (3.32) with placebo (n = 26). The mean difference in percentage body weight change for liraglutide, 3.0 mg, vs placebo was -8.03 (95% CI, -10.39 to -5.66; P < .001). Adverse events, predominantly gastrointestinal, were more frequent with liraglutide, 3.0 mg (28 events [80%]), than placebo (20 events [57%]). There were no serious adverse events and no treatment-related deaths. These findings support the use of adjuvant liraglutide, 3.0 mg, for weight management in patients with poor weight loss and suboptimal GLP-1 response after metabolic surgery. ClinicalTrials.gov Identifier: NCT03341429.

Microbial metabolite p-cresol inhibits gut hormone expression and regulates small intestinal transit in mice.

p-cresol is a metabolite produced by microbial metabolism of aromatic amino acid tyrosine. p-cresol and its conjugated forms, p-cresyl sulfate and p-cresyl glucuronide, are uremic toxins that correlate positively with chronic kidney disease and diabetes pathogenesis. However, how p-cresol affects gut hormones is unclear. Here, we expose immortalized GLUTag cells to increasing concentrations of p-cresol and found that p-cresol inhibited Gcg expression and reduced glucagon-like peptide-1 (GLP-1) secretion in vitro. In mice, administration of p-cresol in the drinking water for 2 weeks reduced the transcript levels of Gcg and other gut hormones in the colon; however, it did not affect either fasting or glucose-induced plasma GLP-1 levels. Furthermore, it did not affect glucose tolerance but promoted faster small intestinal transit in mice. Overall, our data suggest that microbial metabolite p-cresol suppresses transcript levels of gut hormones and regulates small intestinal transit in mice.

Involvement of the vagus nerve in the anorectic effect of monoacylglycerol acyltransferase 2 inhibition in mice.

Many of the drugs used for obesity treatment have adverse effects on the central nervous system. Therefore, novel treatments, such as peripherally acting drugs, are needed. Monoacylglycerol acyltransferase 2 (MGAT2), highly expressed in the small intestine, catalyzes the first step of triacylglycerol re-synthesis. MGAT2 inhibition suppresses food intake in high-fat diet (HFD)-fed mice, but the mechanisms remain unclear. Here, the involvement of the vagus nerve in MGAT2 inhibition-induced feeding suppression was investigated. Fasted mice were administered an MGAT2 inhibitor. Food intake was measured after HFD re-feeding, and the effect of capsaicin pretreatment on changes in food intake was evaluated. The number of c-fos-positive cells in the nucleus tractus solitarius and levels of appetite regulators were determined after HFD re-feeding or lipid gavage. The anorectic effect of the MGAT2 inhibitor was abolished when vagus nerve function was interrupted by capsaicin. MGAT2 inhibition increased the number of c-fos-positive cells in the nucleus tractus solitarius and elevated intestinal oleoylethanolamide, plasma peptide tyrosine-tyrosine and plasma glucagon-like peptide-1 levels. MGAT2 inhibition suppresses feeding behavior via peripheral vagus nerve signaling and may serve as a novel anti-obesity strategy with a low risk of unexpected central nervous system-related adverse effects.

A New Hope for Treating Obesity Pandemic

A new class of drugs is transforming obesity treatment in an unprecedented manner. Scientists are amazed by their potency in the treatment of obesity. Glucagon-like peptide 1 (GLP-1) analogs are a class of medications used to treat type 2 diabetes mellitus. These analogs mimic the action of GLP-1, a hormone released by the intestine in response to food intake. GLP-1 analogs have been extensively studied, and scientists have made several important discoveries about their effects and potential therapeutic applications. GLP-1 analogs have shown significant efficacy in improving glycemic control in patients with type 2 diabetes. They stimulate insulin secretion from pancreatic beta cells, suppress glucagon secretion (which reduces hepatic glucose production), and slow down gastric emptying, leading to reduced postprandial glucose levels. Apart from their controlling glycemic index, GLP-1 analogs are shown to offer cardio-protective, reno-protective, and neuroprotective benefits. However, their most surprising and potent effects have been observed in the context of weight loss. Two drugs from this class, semaglutide, and tripeptide, have shown efficacy in recent clinical trials. Tirzepatide was effective in significantly reducing body weight in about half of the participants in a recent clinical trial. In another trial, semaglutide was able to reduce 20% of the body weight of about one-third of the participants. However, not everyone is benefiting from these medications. There are still significant challenges in determining who will benefit from these medications and to what extent. These challenges are currently being addressed. It has been observed that the new drugs work best in people who become hungry in between meals. People with obesity can be classified into four categories; those who need to eat more to reach fullness; those who reach fullness with a regular-sized meal but feel hungry again soon (hungry gut); those who eat to cope with emotions; and those with a relatively slow metabolism. It is not known why people with a ‘hungry gut’ respond most effectively to the new drugs, but one hypothesis suggests that these patients have low levels of GLP-1 hormones, and that’s why they have obesity. When they get a replacement in the form of GLP-1 analogs, they do extremely well. Another study with a GLP-1-mimicking drug called liraglutide found that patients with low GLP-1 levels reduced twice as much weight compared to the general population after using the drug for one year. Both semaglutide and tripeptide are given once weekly, thus increasing treatment compliance. Because of their weekly regimen, the drugs will also help people with erratic schedules and work shifts. Some of the other medications have to be taken at a certain time of day, which can be difficult for those with irregular sleep schedules. Another important question is to find out how long these drugs' weight loss benefits remain. One study concluded that semaglutide’s weight-reducing effects last as long as the patients remain on medication. This means that these drugs will be given chronically to obese patients. Whether ‘chronic’ means ‘life-long’ in this context is still to be determined. Perhaps an even more important question that clinicians face is determining how much weight loss is too much, especially when muscle loss is also involved. More research is needed to find a balance where these drugs are used not only for weight reduction but to treat a person for health, prevent disease, and improve quality of life.

Metformin and sitagliptin fixed combination as the optimal choice in solving current problems in the type 2 diabetes mellitus treatment

The complex pathogenesis of type 2 diabetes mellitus (DM) is the basis for providing the therapeutic treatment for various disorders, which ensures a better glucose-lowering potential and maintenance of glycemic control as the disease progresses. A key reason for poor glycemic control is clinical inertia, which can be overcome by using antidiabetic fixed-dose combinations (FC). Their use improves glycemic control, as the multidirectional action of the combination components on the pathogenetic mechanisms of type 2 diabetes leads to increased pharmacological effects. The PK of metformin and sitagliptin is preferable in terms of glucose-lowering efficacy, safety and clinical benefits. The mechanism of action of metformin is not associated with the stimulation of insulin secretion by β-cells, but results from the drug’s effect on insulin sensitivity at the level of the liver, muscle and adipose tissue, although the effect on hepatic glucose production is the prevailing one. The mechanism of action of sitagliptin, a highly selective inhibitor of dipeptidyl peptidase-4, is additional to the basic pharmacological effects of metformin, which are caused by several mechanisms not associated with stimulation of insulin secretion by β-cells. The simultaneous use of sitagliptin and metformin has additive effects on the increase of glucagon-like peptide-1 levels. This action is implemented through various mechanisms, while metformin increases the release, and sitagliptin inhibits the active degradation of glucagon-like peptide-1. The article emphasizes the importance of rational combinations of glucose-lowering drugs, the need for a personalized approach to the choice of medicines. The current possibilities of sugar-reducing therapy, the issues of efficacy, safety and benefits of PK of metformin and sitagliptin are discussed using modern evidence-based data.

1753-P: Islet GLP-1R Protein Expression Is Reduced in Humans with Cystic Fibrosis–Related Diabetes

Impaired insulin secretion underlies the development of cystic fibrosis-related diabetes (CFRD). Glucagon like peptide-1 (GLP-1) is produced in islet α cells, and potentiates insulin secretion by binding GLP-1 receptors (GLP-1Rs) on β cells. In CFRD, α-cell mass is increased. Despite this, we hypothesized that levels of GLP-1 and/or its signaling components are reduced in CFRD, thereby contributing to deficits in insulin secretion. To address our hypothesis, paraffin-embedded pancreas sections from humans with CFRD and age-matched nondiabetic controls (from nPOD) underwent immunohistochemistry to quantify protein levels of active GLP-1 and GLP-1R (n=5-6/group). Spatial transcriptomics (NanoString) was also performed to assess differentially expressed α- and/or β-cell genes between CFRD and control pancreas (n=3/group; 15 CFRD + 9 control islets). GLP-1 immunoreactivity was unchanged between CFRD and control pancreas (0.33±0.15 vs 0.51±0.15, % GLP-1 area/pancreas area; p=0.4), however islet GLP-1R immunoreactivity was significantly reduced (4.35±1.21 vs 18.70±0.50, % GLP-1R area/islet area; p=0.004). Surprisingly, few α- or β-cell genes were differentially expressed between CFRD and control islets. However, a gene set test (ROAST) to assess transcripts involved in GLP-1 production/signaling revealed that those in α cells (GCG, PCSK1, PCSK2, DPP-4) significantly changed in mixed directions (up- or down-regulated; p=0.001). No such perturbation was seen in the β-cell gene set (INS, GLP1R, DPP-4, PLCG1, PIP4P2, ITPR3, ADCY1, ADCY6, PRKACA, RAPGEF4; p=0.4). In sum, our data suggest CFRD is not associated with altered intra-islet GLP-1 levels, however α-cell genes that modulate GLP-1 levels are dysregulated. Also, islet GLP-1R protein levels are reduced, though expression of genes downstream of GLP-1R is unchanged. Thus, interventions to restore protein levels of islet GLP-1R and/or promote intracellular signaling beyond GLP-1R may improve β-cell function in CFRD. Disclosure R. Vemireddy: None. J.J. Castillo: None. B.S. Fountaine: None. T.K. Bammler: None. J. MacDonald: None. R.L. Hull-Meichle: Research Support; Casma Therapeutics, Cystic Fibrosis Foundation, NIH - National Institutes of Health. Employee; Veterans Administration. Research Support; Veterans Administration. S. Gharib: None. S. Zraika: None. Funding National Institutes of Health (P30DK089507, P30DK017047)

1300-P: Glucagon-Like Peptide-1 Levels Mirror Insulin Resistant States in Treatment-Naïve Type 2 Diabetes Mellitus

Introduction: In some Asian populations incretin system has been shown to be preserved in type 2 diabetes mellitus (T2DM). The association between fasting and post-OGTT glucagon-like peptide-1 (GLP-1) levels and insulin resistance in treatment-naïve T2DM population has not been clearly defined. Aim: To assess the insulin resistant states (IRS) by means of insulin resistance index (HOMA-IR) and relate this to the fasting and post-OGTT GLP-1 responses in treatment-naïve T2DM. Methods : Thirty-one treatment-naive T2DM subject underwent a 75-g OGTT. Fasting plasma glucose and insulin levels were obtained for HOMA-IR analyses along with plasma total GLP-1 concentrations measured at 0, 30 and 120 min. Results: Majority of the treatment-naïve T2DM patients were newly-diagnosed (n=28, 96.6%). The GLP-1 levels at 0, 30- and 120-min were 25.59 ± 10.87 pmol/L, 46.86 ± 18.36 pmol/L and 27.02 ± 13.37 pmol/L respectively. Fasting GLP-1, incremental GLP-1 at 30 min (∆GLP-130min) and ∆GLP-1120min were positively correlated with HOMA-IR (r=0.654, p&amp;lt;0.001; r=0.421, p=0.018; r=0.574, p=0.001 respectively). Conclusions: The novel finding of this study is that fasting and post-OGTT GLP-1 levels increased proportionately to IRS. This suggests an adaptive compensatory GLP-1 responses to overcome the worsening insulin resistance in treatment-naïve newly-diagnosed T2DM patients. Disclosure S.Chong: None. N.Sukor: None. S.A.Robert: None. K.Ng: None. N.A.Kamaruddin: Advisory Panel; Zuellig Pharma Holdings Pte. Ltd., Other Relationship; American Association of Clinical Endocrinologists, Speaker's Bureau; AstraZeneca, Boehringer-Ingelheim, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novo Nordisk. Funding National University of Malaysia (GUP-2017-066); Malaysian Endocrine &amp; Metabolic Society (L12-MEMS6)

1299-P: Predictors of Glucagon-Like Peptide-1 Responses following OGTT in Treatment-Naïve Type 2 Diabetes Mellitus among Three Ethnic Groups in Malaysia

Introduction: Predictors of glucagon-like peptide-1 (GLP-1) responses following OGTT in treatment-naïve type 2 diabetes mellitus (T2DM) have not been fully elucidated. In this respect, we aim to investigate the various predictors of GLP-1 responses following OGTT in treatment-naïve T2DM. Aim: To assess the clinical and biochemical predictors of GLP-1 responses following OGTT in treatment-naïve T2DM among three ethnic groups in Malaysia. Methods : Thirty-one treatment-naive T2DM subjects underwent a 75-g OGTT. Total GLP-1 concentrations were measured at 0, 30 and 120 min. By using area under the curve (AUC) for GLP-1 (AUCGLP-1) as an index of GLP-1 secretory response, predictors of GLP-1 responses following OGTT were assessed using multiple linear regression analysis. Results: Majority of the treatment-naïve T2DM patients were newly-diagnosed (n=28, 96.6%). The GLP-1 levels at 0, 30- and 120-min were 25.59 ± 10.87 pmol/L, 46.86 ± 18.36 pmol/L and 27.02 ± 13.37 pmol/L respectively. There was a positive correlation between increasing age and AUCGLP-1 (Β = 8.55, p&amp;lt;0.001). Male had higher GLP-1 response to OGTT than female (Β = -303.04, p&amp;lt;0.001). The Indian ethnicity exhibited higher GLP-1 secretion than the Malays (Β = 244.17, p&amp;lt;0.001). Fasting insulin was positively correlated with AUCGLP-1 (Β = 8.73, p=0.001). AUCGLP-1 was positively correlated with increased systolic blood pressure (Β = 3.65, p=0.03), total cholesterol (Β = 174.32, p=0.004) and LDL-cholesterol (Β = 202.35, p=0.002). Conclusions: Older age, male and Indian ethnicity were independent predictors of GLP-1 responses following OGTT in treatment-naïve T2DM. The positive correlation between risk factors associated with insulin resistance and GLP-1 suggested that these risk factors are responsible for driving GLP-1 secretion. Disclosure S.Chong: None. N.Sukor: None. S.A.Robert: None. K.Ng: None. N.A.Kamaruddin: Advisory Panel; Zuellig Pharma Holdings Pte. Ltd., Other Relationship; American Association of Clinical Endocrinologists, Speaker's Bureau; AstraZeneca, Boehringer-Ingelheim, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novo Nordisk. Funding National University of Malaysia (GUP-2017-066); Malaysian Endocrine &amp; Metabolic Society (L12-MEMS6)

Effect of dipeptidyl peptidase-4 inhibitors on glycated hemoglobin levels relies on dietary sodium intake

AimsSodium load increases endogenous glucagon-like peptide-1 (GLP-1) levels in humans. Therefore, patients with an increased amount of dietary sodium intake are supposed to have higher endogenous GLP-1 levels compared to those with less dietary sodium intake. Therefore, it can be hypothesized that patients with type 2 diabetes mellitus (T2DM) with more dietary sodium intake show better dipeptidyl peptidase-4 inhibitor (DPP-4i) effect on glycemic control because of the expected higher GLP-1 level. Thus, we performed a single-center cohort study to explore this idea. MethodsMedical records of patients with T2DM prescribed DPP-4i in the last 11 years were investigated. Dietary sodium intake was measured before the DPP-4i prescription with Tanaka's formula using casual spot urine samples. The effect of DPP-4i on glycemic control was estimated by the subtraction of glycated hemoglobin (HbA1c) before DPP-4i initiation from HbA1c 1 year after DPP-4i administration. We analyzed 50 patients. ResultsDPP-4i improved HbA1c by −0.41% ± 0.66%. The effect of DPP-4i on glycemic control was significantly negatively correlated with the dietary sodium intake (r = −0.400). Thus, the more dietary sodium intake, the better the glycemic control by DPP-4i. ConclusionsThus, patients can expect better plasma glucose control by DPP-4is if patients are taking increased dietary sodium intake.

#4945 NEPHROPROTECTIVE EFFECTS OF DIPEPTIDYL PEPTIDASE–IV INHIBITORS FROM PHENOLIC RICH FRACTION OF TRIGONELLA FOENUM IN DIABETIC NEPHROPATHY RATS

Abstract Background and Aims The most common effect of renal disease in the world is diabetic nephropathy (DN). Dipeptidyl peptidase–IV (DPP-IV) enzyme is most abundant present in kidney, which is increased in diabetic nephropathy. A novel approach to treat type 2 diabetes mellitus (T2DM) along with DN, based on incretin hormones: glucagon-like peptide-1 (GLP-1) which regulated by DPP-IV. We hypothesized that DPP-IV inhibitors isolated from phenolic rich fraction of Trigonella foenum (TF) will regulate DPP-IV activity as well as DN: in-vivo; in-silico and kidney histology. Method DPP-IV inhibitors from phenolic rich fraction of TF in high sucrose diet along with dexamethasone induced T2DM was explored in-vivo in rat. Apart from serum glucose, DPP-IV, and inhibition activity, HbA1c, Insulin was estimated. We also examined GLP-1, albuminuria, and antioxidant properties in kidney tissue along with histology. Molecular docking of phenolic rich fraction (Gallic acid) of TF with DPP-IV Results High sucrose diet with Dexamethasone administration (1 mg /kg BW 45 days) increased concentration of serum glucose, DPP-IV and albuminuria, cholesterol and renal LPO with increase in tissue antioxidant to scavenging free radicals generated by oxidative stress, but after some time antioxidants such as SOD, CAT, GSH was decreased. However, after administration of phenolic rich fraction of TF, DPP-IV inhibition activity increase in TF (71.1%), as compared to Sitagliptin (89.5%) with significant reduction in levels of glucose, albuminuria, TC, TG and with increased Insulin and GLP-1. Kidney histology showed some significant change as compared to diabetes control. Isolated Gallic acid depicts the conformer and affinity energy was – 5.3 and distance from RMSD i.b was 38.669. Sitagliptin depicted the conformer and affinity energy was – 8.9 and distance from RMSD i.b was 3.826. Conclusion DPP-IV inhibitors isolated from TF are nephroprotective, antioxidant with novel antidiabetic properties. DPP-IV inhibition lower blood glucose by decreasing DPP-IV activity, albuminuria and increasing levels of GLP-1

Eicosapentaenoic acid mitigates ulcerative colitis-induced by acetic acid through modulation of NF-κB and TGF-β/ EGFR signaling pathways

BackgroundUlcerative colitis (UC) is a chronic mucosal inflammation of the large intestine that mostly affects the rectum and colon. The absence of safe and effective therapeutic agents encourages the discovery of novel therapeutic agents to effectively treat UC and its complications. The purpose of this research was to examine the protective impact of Eicosapentaenoic acid (EPA) in rats with UC induced by acetic acid (AA). MethodAA (2 ml, 3 % v/v) was injected intrarectally to cause UC. Before administering AA, EPA (300 and 1000 mg/kg) was given orally for 28 days. ResultsEPA inhibited AA-induced UC by enhancing colonic histopathological changes like inflammation, goblet cell loss, glandular hyperplasia and mucosal ulceration, concomitant with a reduction in colon weight, colon weight/length ratio, C-reactive protein (CRP), and serum lactate dehydrogenase (LDH). EPA also effectively restored the imbalance between oxidants and antioxidants caused by AA. In addition, EPA increased the levels of trefoil factor-3 (TFF-3) and glucagon-like peptide-1 (GLP-1), while significantly reducing the expression of nuclear factor kappa B (NF-κB), interferon-γ (IFN-γ), and interleukin-6 (IL-6), transforming growth factor-1(TGF-β1), and phosphorylated epidermal growth factor receptor (P-EGFR), phosphatidylinositol-3-kinase (PI3K) and protein kinase B (AKT) expression in colonic tissues. ConclusionEPA inhibited AA-induced UC in rats by modulating the TGF-β/P-EGFR and NF-κB inflammatory pathways, regulating the oxidant/antioxidant balance, and enhancing the colon barrier integrity.

Circulating levels of proglucagon-derived peptides are differentially regulated by the glucagon-like peptide-1 agonist liraglutide and the centrally acting naltrexone/bupropion and can predict future weight loss and metabolic improvements: A 6-month long interventional study.

To investigate the changes of circulating levels of all proglucagon-derived peptides (PGDPs) in individuals with overweight or obesity receiving liraglutide (3 mg) or naltrexone/bupropion (32/360 mg), and to explore the association between induced changes in postprandial PGDP levels and body composition, as well as metabolic variables, after 3 and 6 months on treatment. Seventeen patients with obesity or with overweight and co-morbidities, but without diabetes, were assigned to receive once-daily oral naltrexone/bupropion 32/360 mg (n = 8) or once-daily subcutaneous liraglutide 3 mg (n = 9). Participants were assessed before treatment initiation and after 3 and 6 months on treatment. At the baseline and 3-month visits, participants underwent a 3-hour mixed meal tolerance test to measure fasting and postprandial levels of PGDPs, C-peptide, hunger and satiety. Clinical and biochemical indices of metabolic function, magnetic resonance-assessed liver steatosis and ultrasound-assessed liver stiffness were measured at each visit. Both medications improved body weight and composition, carbohydrate and lipid metabolism, and liver fat and function. Naltrexone/bupropion produced a weight-independent increase in the levels of proglucagon (P < .001) and decreases in glucagon-like peptide-2 (GLP-2), glucagon and the major proglucagon fragment (P ≤ .01), whereas liraglutide markedly upregulated total glucagon-like peptide-1 (GLP-1) levels in a weight-independent manner (P = .04), and similarly downregulated the major proglucagon fragment, GLP-2 and glucagon (P < .01). PGDP levels at the 3-month visit were positively and independently correlated with improvements in fat mass, glycaemia, lipaemia and liver function, and negatively with reductions in fat-free mass, at both the 3- and 6-month visits. PGDP levels in response to liraglutide and naltrexone/bupropion are associated with improvements in metabolism. Our study provides support for the administration of the downregulated members of the PGDP family as replacement therapy (e.g. glucagon), in addition to the medications currently in use that induced their downregulation (e.g. GLP-1), and future studies should explore whether the addition of other PGDPs (e.g. GLP-2) could offer additional benefits.

CCK and GLP-1 response on enteroendocrine cells of semi-dynamic digests of hydrolyzed and intact casein

A semi-dynamic gastrointestinal device was employed to explore the link between protein structure and metabolic response upon digestion for two different substrates, a casein hydrolysate and the precursor micellar casein. As expected, casein formed a firm coagulum that remained until the end of the gastric phase while the hydrolysate did not develop any visible aggregate. Each gastric emptying point was subjected to a static intestinal phase where the peptide and amino acid composition changed drastically from that found during the gastric phase. Gastrointestinal digests from the hydrolysate were characterized by a high abundancy of resistant peptides and free amino acids. Although all gastric and intestinal digests from both substrates induced the secretion of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) in STC-1 cells, GLP-1 levels were maximum in response to gastrointestinal digests from the hydrolysate. The enrichment of protein ingredients with gastric-resistant peptides by enzymatic hydrolysis is proposed as strategy to deliver protein stimuli to the distal gastrointestinal tract to control food intake or type 2 diabetes.

Insulin secretory actions of ethanolic extract of Acacia arabica bark in high fat-fed diet-induced obese Type 2 diabetic rats.

Acacia arabica commonly known as 'babul' has been widely used for the treatment of numerous diseases, including diabetes due to their potential pharmacological actions. The aim of the present study was to investigate the insulinotropic and antidiabetic properties of ethanol extract of Acacia arabica (EEAA) bark through in vitro and in vivo studies in high fat-fed (HFF) rats. EEAA at 40-5000 µg/ml significantly increased (P<0.05-0.001) insulin secretion with 5.6 and 16.7 mM glucose, respectively, from clonal pancreatic BRIN BD11 β-cells. Similarly, EEAA at 10-40 µg/ml demonstrated a substantial (P<0.05-0.001) insulin secretory effect with 16.7 mM glucose from isolated mouse islets, with a magnitude comparable to 1 µM glucagon-like peptide-1 (GLP-1). Diazoxide, verapamil, and calcium-free conditions decreased insulin secretion by 25-26%. The insulin secretory effect was further potentiated (P<0.05-0.01) with 200 µM isobutylmethylxanthine (IBMX; 1.5-fold), 200 µM tolbutamide (1.4-fold), and 30 mM KCl (1.4-fold). EEAA at 40 µg/ml, induced membrane depolarization and elevated intracellular Ca2+ as well as increased (P<0.05-0.001) glucose uptake in 3T3L1 cells and inhibited starch digestion, glucose diffusion, dipeptidyl peptidase-IV (DPP-IV) enzyme activity, and protein glycation by 15-38%, 11-29%, 15-64%, and 21-38% (P<0.05, 0.001), respectively. In HFF rats, EEAA (250 mg/5 ml/kg) improved glucose tolerance, plasma insulin, and GLP-1 levels, and lowered DPP-IV enzyme activity. Phytochemical screening of EEAA revealed the presence of flavonoids, tannins and anthraquinone. These naturally occurring phytoconstituents may contribute to the potential antidiabetic actions of EEAA. Thus, our finding suggests that EEAA, as a good source of antidiabetic constituents, would be beneficial for Type 2 diabetes patients.