GLP-1 based therapies: clinical implications for gastroenterologists

Incretin-based drugs and the risk of gallbladder or biliary tract diseases among patients with type 2 diabetes across categories of body mass index: a nationwide cohort study

Background

Despite emerging evidence of gallbladder or biliary tract diseases (GBD) risk regarding incretin-based drugs, population-specific safety profile considering obesity is lacking. We aimed to assess whether stratification by body mass index (BMI) modifies the measures of association between incretin-based drugs and the risk of GBD.

Methods

We conducted an active-comparator, new-user cohort study using a nationwide claims data (2013-2022) of Korea. We included type 2 diabetes (T2D) patients stratified by Asian BMI categories: Normal, 18.5 to <23 kg/m2; Overweight, 23 to <25 kg/m2; Obese, ≥25 kg/m2. The primary outcome was a composite of GBD, including cholelithiasis, cholecystitis, obstruction of the gallbladder or bile duct, cholangitis, and cholecystectomy. We used 1:1 propensity score (PS) matching and estimated hazard ratios (HR) with 95% confidence intervals (CI) using Cox models.

Findings

New users of DPP4i and SGLT2i were 1:1 PS matched (n = 251,420 pairs; 186,697 obese, 39,974 overweight, and 24,749 normal weight pairs). The overall HR for the risk of GBD with DPP4i vs. SGLT2i was 1.21 (95% CI 1.14-1.28), with no effect modification by BMI (p-value: 0.83). For the second cohort, new users of GLP1RA and SGLT2i were 1:1 PS matched (n = 45,443 pairs; 28,011 obese, 8948 overweight, and 8484 normal weight pairs). The overall HR for the risk of GBD with GLP1RA vs. SGLT2i was 1.27 (1.07-1.50), with no effect modification by BMI (p-value: 0.73).

Interpretation

The increased risks of GBD were presented in both cohorts with no evidence of effect heterogeneity by BMI.

Funding

Ministry of Food and Drug Safety, Health Fellowship Foundation.

Perioperative Use of GLP-1 Receptor Agonists in Patients Undergoing Cardiac Procedures: A Scoping Review

BACKGROUND

Glucagon-like peptide-1 receptor agonist (GLP-1RA) therapies are increasingly used for the treatment of type 2 diabetes mellitus and obesity. Despite growing awareness of potentially increased risk of pulmonary aspiration due to delayed gastric emptying, the risks and benefits of their perioperative use in patients undergoing cardiac procedures remains unexplored. A scoping review was performed to investigate the perioperative GLP-1RA use in patients undergoing cardiac procedures and recommendations.

METHOD

PubMed and Ovid MEDLINE were searched up to April 2024 to identify English-language studies on the perioperative use of weekly and daily dosed GLP-1RAs in adult patients undergoing cardiac procedures (including cardiac surgery, trans-oesophageal echocardiograms, and cardiac catheterisation procedures).

RESULTS

Three studies were identified, which investigated daily dosed GLP-1RAs in patients undergoing cardiac surgery. No studies were found investigating GLP-1RA use in cardiac catheterisation or trans-oesophageal echocardiograms procedures, and none which specifically examined risk of pulmonary aspiration in patients using GLP-1RAs undergoing cardiac procedures.

CONCLUSIONS

GLP-1RAs are beneficial for perioperative weight loss, glycaemic control, and cardiovascular health. Existing guidelines and consensus recommendations are highly contradictory on perioperative GLP-1RA management. Although no known published case reports exist to date of pulmonary aspiration in patients using GLP-1RAs undergoing cardiac procedures, non-cardiac surgical literature strongly suggests that patients are at theoretical risk and a cautious approach is advised in the absence of robust evidence informing recommendations for optimal withholding periods.

Glucagon-like peptide-1 receptor agonists and type 1 diabetes: a potential game changer?

This mini review explores the increasing prevalence of obesity in type 1 diabetes (T1D) and the challenges patients face in achieving optimal glycemic control with current treatments. It discusses the evidence supporting the use of glucagon-like peptide-1 receptor agonists (GLP-1RA) as potential adjunctive therapy in T1D to reduce weight and improve insulin resistance. Potential benefits need to be weighed against the risk of hypoglycemia and lack of long-term data.

The relative risk of clinically relevant cholelithiasis among glucagon-like peptide-1 receptor agonists in patients with type 2 diabetes mellitus, real-world study

BACKGROUND AND AIM

The association between biliary disorders with weight reduction enhanced by GLP-1RAs was observed frequently, nevertheless, the relative risk of the clinically relevant cholelithiasis was not specified clearly among different GLP-1RAs.

METHODS

308 patients with type 2 diabetes mellitus (T2D) were recruited and divided into 4 groups; liraglutide, dulaglutide, semaglutide, versus control group; comprised of 69, 76, 71, and 92, respectively. Clinical history, examination, laboratory, and radiology tests were implemented.

RESULTS

Cholelithiasis significantly associates GLP1-RAs (p = 0.033). Overall cholelithiasis was evident in 31.2% of our participants. Symptomatic cholelithiasis prevails in 60.4% of patients with cholelithiasis. Symptomatic complicated cholelithiasis prevailed in 33.3%; distributed in 28.1%, 28.1%, 21.9%, and 21.9% in liraglutide, semaglutide, dulaglutide, and control groups, respectively. Meanwhile, symptomatic uncomplicated cholelithiasis was observed in 27.1%; distributed in 34.6%, 30.8%, 15.4%, and 19.2% in Liraglutide, semaglutide, dulaglutide, and control groups, respectively. Asymptomatic cholelithiasis was noted in 36.8%, 21.1%, 10.5%, and 31.6% of patients with dulaglutide, semaglutide, liraglutide, and control groups, respectively. Specifically, 81.1%, 68%, and 44% of patients with liraglutide, semaglutide, and dulaglutide experienced symptomatic cholelithiasis. The relative risk of cholelithiasis was 1.2, 1.3, and 1.4 in liraglutide, dulaglutide, and semaglutide with number needed to harm of 17.25, 14.69, and 10.96, respectively. The relative risk of symptomatic cholelithiasis was 1.6, 0.9, and 1.4 in liraglutide, dulaglutide, and semaglutide with number needed to harm of 3.14, 16.67, and 5.56, respectively.

CONCLUSION

Liraglutide was associated with the highest risk of clinically relevant cholelithiasis than semaglutide, and dulaglutide in patients with T2D.

A Specific Collagen Hydrolysate Improves Postprandial Glucose Tolerance in Normoglycemic and Prediabetic Mice and in a First Proof of Concept Study in Healthy, Normoglycemic and Prediabetic Humans

In response to nutrients, intestinal L- and K-cells naturally secrete glucagon-like peptide 1 (GLP-1). GLP-1 regulates postprandial blood glucose by increasing insulin secretion, slowing down gastric emptying and inducing satiety. A selection of specifically developed collagen hydrolysates was screened for their ability to enhance natural GLP-1 production in vitro. The best performing hydrolysate, H80 (Nextida GC), was orally administered at different doses to lean, normoglycemic mice and overweight, prediabetic mice. Lean mice were acutely challenged 45 min before an oral glucose load. While daily supplemented for 6 weeks, prediabetic mice were acutely challenged at day 21 and 34. Oral glucose tolerance, plasma insulin and GLP-1 levels were assessed, and a gastric emptying assay performed in prediabetic mice. H80 significantly lowered the blood glucose response in lean and prediabetic mice, at a 4 g/kg dose (-25% and -36%, respectively), compared to vehicle. In chronically supplemented, prediabetic mice, acute H80 administration slowed down gastric emptying (-60%) after 21 days and increased plasma insulin (+166%) after 35 days of supplementation. H80 increased plasma active GLP-1 in lean (+217%) and prediabetic (+860%) mice. Overall, the data indicate that the specific collagen hydrolysate, H80, has significant GLP-1-mediated effects on oral glucose tolerance in lean and prediabetic mice. Furthermore, effects on postprandial glucose tolerance were evaluated in a small, human, proof of concept study. H80 reduced the postprandial glucose response at a 5 g dose in healthy, normoglycemic and prediabetic participants. Oral supplementation with H80 might thus be a promising strategy to maintain normal glucose tolerance.

Achyranthes bidentata polysaccharide ameliorates type 2 diabetes mellitus by gut microbiota-derived short-chain fatty acids-induced activation of the GLP-1/GLP-1R/cAMP/PKA/CREB/INS pathway

Gut microbiota variances reflecting the severity type 2 diabetes mellitus (T2DM). Achyranthes bidentata polysaccharide (ABP) can regulate gut microbiota. However, the hypoglycemic effect and underlying mechanism of ABP remain unclear. Herein, we characterized the structure of ABP and revealed the hypoglycemic effect of ABP in mice with T2DM. ABP repaired the intestinal barrier in T2DM mice and regulated the composition and abundance of gut microbiota, especially increasing bacteria which producing short-chain fatty acids (SCFAs), then increasing glucagon-like peptide-1 (GLP-1) level. The abundance of these bacteria was positively correlated with blood lipid and INS levels, negatively correlated with FBG levels. Colon transcriptome data and immunohistochemistry demonstrated that the alleviating T2DM effect of ABP was related to activation of the GLP-1/GLP-1 receptor (GLP-1R)/cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA)/cAMP-response element binding protein (CREB)/INS pathway. Fecal microbiota transplantation (FMT) confirmed the transmissible efficacy of ABP through gut microbiota. Overall, our research shows that ABP plays a hypoglycemic role by increasing gut microbiota-derived SCFAs levels, and activating the GLP-1/GLP-1R/cAMP/PKA/CREB/INS pathway, emphasizing ABP as promising T2DM therapeutic candidates.

Vertical sleeve gastrectomy improves glucose-insulin homeostasis by enhancing β-cell function and survival via FGF15/19

Vertical sleeve gastrectomy (VSG) restores glucose homeostasis in obese mice and humans. In addition, the increased fibroblast growth factor (FGF)15/19 circulating level postsurgery has been implicated in this effect. However, the impact of FGF15/19 on pancreatic islets remains unclear. Using a diet-induced obese mice model, we demonstrate that VSG attenuates insulin hypersecretion in isolated pancreatic islets, likely due to morphological alterations in the endocrine pancreas such as reduction in islet, β-cell, and α-cell mass. In addition, VSG relieves gene expression of endoplasmic reticulum (ER) stress and inflammation markers in islets from obese mice. Incubation of INS-1E β-cells with serum from obese mice induced dysfunction and cell death, whereas these conditions were not induced with serum from obese mice submitted to VSG, implicating the involvement of a humoral factor. Indeed, VSG increased FGF15 circulating levels in obese mice, as well as the expression of FGF receptor 1 (Fgfr1) and its coreceptor β-klotho (Klb), both in pancreatic islets from VSG mice and in INS-1E cells treated with the serum from these mice. Moreover, exposing INS-1E cells to an FGFR inhibitor abolished the effects of VSG serum on insulin secretion and cell death. Also, recombinant FGF19 prevents INS-1E cells from dysfunction and death induced by serum from obese mice. These findings indicate that the amelioration of glucose-insulin homeostasis promoted by VSG is mediated, at least in part, by FGF15/19. Therefore, approaches promoting FGF15/19 release or action may restore pancreatic islet function in obesity.NEW & NOTEWORTHY Vertical sleeve gastrectomy (VSG) decreases insulin secretion, endoplasmic reticulum (ER) stress, and inflammation in pancreatic islets from obese mice. In addition, VSG increased fibroblast growth factor (FGF)15 circulating levels in obese mice, as well as the expression of FGF receptor 1 (Fgfr1) and its coreceptor β-klotho (Klb), both in pancreatic islets from VSG mice and in INS-1E β-cells treated with the serum from these mice. Serum from operated mice protects INS-1E cells from dysfunction and apoptosis, which was mediated by FGF15/19.

The Antidepressant Effects of GLP-1 Receptor Agonists: A Systematic Review and Meta-Analysis

AIM/HYPOTHESIS

Emerging evidence suggests that glucagon-like peptide-1 receptor agonists (GLP-1RAs) may exert positive effects in patients with depression. Our aim was to conduct a systematic review and meta-analysis to examine the antidepressant effects of GLP-1RAs.

METHODS

Randomized controlled trials and prospective cohort studies investigating the effects of GLP-1RAs versus placebo or other antidiabetic therapies on depressive symptoms were searched for using multiple electronic sources (CENTRAL, PubMed, EMBASE, PsycINFO, World Health Organization International Clinical Trials Registry Platform, ClinicalTrials.gov, China Network Knowledge Infrastructure, China Biomedical Database, Wan Fang data, and Chinese Scientific Journals Database) from inception to February 16, 2023. We utilized a random effects model to analyze standardized mean differences for the change in depression rating scales comparing GLP-1RA treated groups with control treated groups.

RESULTS

The meta-analysis comprising 2,071 participants included 5 randomized controlled trials and 1 prospective cohort study. The meta-analysis indicated that the change from baseline in depression rating scale scores decreased significantly when patients received treatment with GLP-1RAs compared to control treatments (SMD = -0.12, 95% CI [-0.21, -0.03], pSMD <0.01, I2 = 0%, pQ = 0.52). The subgroup analysis showed that the effects of GLP-1RAs on depressive symptoms were consistent in patients with Type 2 diabetes mellitus (SMD = -0.12, 95% CI [-0.21, -0.03], pSMD <0.01, I2 = 2%, pQ = 0.40).

CONCLUSIONS

Adults treated with GLP-1RAs showed significant reductions in the depression rating scale scores compared to those treated with control substances. Our findings suggest that GLP-1RAs may be a potential treatment for alleviating depressive symptoms in humans.

Particulate Gastric Contents in Patients Prescribed Glucagon-Like Peptide 1 Receptor Agonists After Appropriate Perioperative Fasting: A Report of 2 Cases

Glucagon-like peptide 1 (GLP-1) receptor agonists have surged in popularity for the treatment of both diabetes mellitus and obesity. While GLP-1 reduces proximal gastrointestinal motility and delays gastric emptying, the impact of these medications on adequate fasting before surgery is not clear. We present 2 cases of particulate gastric contents after following appropriate presurgical fasting in diabetic patients taking GLP-1 receptor agonists and review current literature regarding perioperative implications of these drugs.

Pancreatic exocrine insufficiency after bariatric surgery

BACKGROUND

Chronic abdominal complaints after bariatric surgery may be explained by pancreatic exocrine insufficiency (PEI).

OBJECTIVES

We aimed to evaluate the clinical value of the Pancreatic Exocrine Insufficiency Questionnaire (PEI-Q) as a screening tool to identify patients with a high probability of having PEI.

SETTING

Outpatient clinic for bariatric surgery.

METHODS

Patients scheduled for a screening or follow-up appointment were asked to complete the PEI-Q and the Gastrointestinal Quality of Life Index questionnaire (GIQLI). Postoperative patients with a high PEI-Q score (0,6) were offered a fecalelastase (FE) test (abnormal if <200 μg/g).

RESULTS

Between June 2020 and February 2021, a total of 1600 of 1629 PEI-Qs were completed, 1073 (67%) of which after surgery. The postoperative group consisted mostly of females (81.9%), aged 49.0 ± 10.6 years, with a total weight loss of 30.3% ± 8.8%. Among them, 63.4% had abnormal PEI-Q scores compared with 34.9% before surgery (P < .01). In contrast, the median GIQLI score increased (119 [interquartile range (IQR), 107-129.25] versus 110 [IQR, 95-121.75]) before surgery (P < .01). Additionally, 310 FE tests were performed, of which only 11.9% was suggestive of PEI. No correlation was found between the PEI-Q scores and FE levels (c-index .55).

CONCLUSION

The PEI-Q in its current version is not able to distinguish complaints of PEI and bariatric surgery itself and therefore cannot be used as a screening tool for PEI. The specificity of the FE test seems to be reduced after surgery. Future research should include a more direct pancreatic function test, which may provide more insight into PEI after bariatric surgery.

GLP-1 Receptor Agonists in Diabetic Kidney Disease: From Physiology to Clinical Outcomes

Diabetic kidney disease (DKD) is one of the most common complications in type 2 diabetes mellitus (T2D) and a major cause of morbidity and mortality in diabetes. Despite the widespread use of nephroprotective treatment of T2D, the incidence of DKD is increasing, and it is expected to become the fifth cause of death worldwide within 20 years. Previous studies have demonstrated that GLP-1 receptor agonists (GLP-1 RA) have improved macrovascular and microvascular outcomes independent of glycemic differences, including DKD. GLP-1Ras’ improvement on kidney physiology is mediated by natriuresis, reduction in hyperfiltration and renin-angiotensin-aldosterone system (RAAS) activity and anti-inflammatory properties. These findings translate into improved clinical outcomes such as an enhanced urine albumin-to-creatinine ratio (UACR) and a reduction in renal impairment and the need for renal replacement therapies (RRT). In this article, we review the role of GLP-1RAs on the mechanisms and effect in DKD and their clinical efficacy.

Renoprotection in diabetic kidney disease: can incretin-based therapies deliver?

PURPOSE OF REVIEW

Incretin-based therapies mimic or augment the gut-hormone glucagon-like peptide (GLP)-1 and, due to their glucose-lowering potential and beneficial safety profile, as well as their cardiovascular safety and/or protection, are prescribed on a large scale to treat individuals with type 2 diabetes (T2D). However, whether the two drug-classes that belong to this category, respectively GLP-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors, also reduce the risk of diabetic kidney disease (DKD) is at present heavily debated. This review aims to discuss the current evidence.

RECENT FINDINGS

Evidence from land-mark cardiovascular safety trials, conducted in people with T2D at high-cardiovascular risk but with normal kidney function, suggest that both drug-classes have excellent renal safety profiles. In contrast to DPP-4 inhibitors, it seems that GLP-1 receptor agonists reduce albuminuria and possibly induce a reduction of estimated glomerular filtration rate decline. However, the trials were not properly designed to test renal outcomes.

SUMMARY

A dedicated renal trial involving a GLP-1 receptor agonist has recently commenced and will answer the question whether these drugs will be effective to reduce DKD. Moreover, ongoing mechanism-of-action studies are focusing on the renal physiological effects of GLP-1, as the effects on particularly albuminuria reduction remain currently unexplained.

Intestinal fatty acid-binding protein, a biomarker of intestinal barrier dysfunction, increases with the progression of type 2 diabetes

OBJECTIVE

To investigate serum intestinal fatty acid-binding protein (I-FABP) in two groups of patients with different duration of hyperglycemia in a cross-sectional study.

MATERIALS AND METHODS

In the present study, a total of 280 individuals (158 outpatients and 122 inpatients) suffering from hyperglycemia were recruited between May and September 2019. The clinical information of all participants was collected from the hospital information system, including the duration of hyperglycemia, age, gender, hemoglobin A1c (HbA1c), 75-g oral glucose tolerance test including fasting plasma glucose (FPG), 2-hour plasma glucose (2hPG), fasting C-peptide (FC-pep), 2-hour C-peptide (2hC-pep), fasting insulin (FIns), and 2-hour insulin (2hIns). In addition, the morbidity of diabetic complications (retinopathy, neuropathy, and nephropathy) in the inpatient group was determined. Furthermore, the difference between 2hPG and FPG (ΔPG), the difference between 2hC-pep and FC-pep (ΔC-pep), and the difference between 2hIns and FIns (ΔIns) were calculated. The level of serum I-FABP, a biomarker of intestinal barrier (IB) dysfunction, was estimated by an enzyme-linked immunosorbent assay.

RESULTS

For the outpatient group, the median duration of hyperglycemia was less than a year; the serum I-FABP level was positively correlated with age (R = 0.299, P < 0.001). For the inpatient group, the median duration of hyperglycemia was ten years; correlation analysis showed that the serum I-FABP level was positively associated with age and ΔPG (R = 0.286, P = 0.001; R = 0.250, P = 0.006, respectively) while negatively associated with FC-pep and 2hC-pep (R =  - 0.304, P = 0.001; R =  - 0.241, P = 0.008, respectively); multiple linear regression analysis showed that the serum I-FABP level was positively associated with the duration of hyperglycemia (β = 0.362, P < 0.001); moreover, patients with retinopathy had a significantly higher I-FABP level than those without retinopathy (P = 0.001).

CONCLUSIONS

In the outpatients whose duration of hyperglycemia was less than a year, the serum I-FABP level was positively associated with age. In the inpatients with different courses of diabetes, the serum I-FABP level was positively associated with the duration of hyperglycemia and glycemic variability but negatively associated with islet beta-cell function; moreover, the serum I-FABP level was higher in patients with retinopathy than in those without retinopathy, suggesting that the IB dysfunction got worse with the progression of diabetes.

Liraglutide or insulin glargine treatments improves hepatic fat in obese patients with type 2 diabetes and nonalcoholic fatty liver disease in twenty-six weeks: A randomized placebo-controlled trial

BACKGROUND

Type 2 diabetes mellitus is closely related to nonalcoholic fatty liver disease(NAFLD). More and more attention has been paid to the efficacy of liraglutide in the treatment of NAFLD, but the clinical evidence is still insufficient.

OBJECTIVE

The purpose of this study was to use proton magnetic resonance spectroscopy (H-MRS) assessment of metformin alone poor blood glucose control of obese patients type 2 diabetes with NAFLD, added with insulin glargine, liraglutide or placebo effect in improving the fatty liver.

METHODS

This is a 26-week, single-center, prospective, randomized placebo-controlled study. From September 2016 to July 2018, 128 patients with type 2 diabetes and NAFLD were enrolled in the China joint logistics team 900 hospital. The primary endpoints were the changes in intrahepatic content of lipid (IHCL), abdominal adiposity [subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT)], from baseline to week 26 (end of treatment) and the changes in liraglutide group or insulin glargine group versus change in placebo group. Secondary endpoints included the changes in liver function (AST and ALT), glycemia (HbA1c and FPG), body weight, and BMI.

RESULTS

A total of 96 patients with type 2 diabetes and NAFLD under inadequate glycemic control by metformin were randomized (1:1:1) to receive add-on insulin glargine, liraglutide, or placebo. After 26 weeks of treatment, compared to the placebo group, in the liraglutide and insulin glargine groups, IHCL significantly decreased from baseline to week 26 (liraglutide 26.4% ± 3.2% to 20.6% ± 3.9%, P < 0.05; insulin glargine 25.0% ± 4.3% to 22.6% ± 5.8%, P > 0.05). SAT and VAT decreased significantly in the liraglutide group and in the insulin glargine group (P < 0.05). ΔSAT and ΔVAT were greater with liraglutide than insulin glargine, they were significantly different between the two groups (ΔSAT, -36 vs. - 24.5, P < 0.05; and ΔVAT, -47 vs. - 16.6, P > 0.05). In the liraglutide group, AST, ALT, and HOMA-IR decreased significantly from baseline. There was no significant difference in glucose-lowering among the three groups. During the treatment, the safety of the three groups performed well.

CONCLUSION

Compared with placebo, treatment with liraglutide plus an adequate dose of metformin (2000 g/ day) for 26 weeks is more effective in reducing IHCL, SAT and VAT in patients with type 2 diabetes and NAFLD. And it has additional advantages in weight loss, waist circumference reduction and liver function improvement.

Cardiovascular effects of glucagon-like peptide 1 receptor agonists: from mechanistic studies in humans to clinical outcomes

Type 2 diabetes mellitus (T2DM) is currently one of the most prevalent diseases, with as many as 415 million patients worldwide. T2DM is characterized by elevated blood glucose levels and is often accompanied by several comorbidities, such as cardiovascular disease. Treatment of T2DM is focused on reducing glucose levels by either lifestyle changes or medical treatment. One treatment option for T2DM is based on the gut-derived hormone glucagon-like peptide 1 (GLP-1). GLP-1 reduces blood glucose levels by stimulating insulin secretion, however, it is rapidly degraded, and thereby losing its glycaemic effect. GLP-1 receptor agonists (GLP-1RAs) are immune to degradation, prolonging the glycaemic effect. Lately, GLP-1RAs have spiked the interest of researchers and clinicians due to their beneficial effects on cardiovascular disease. Preclinical and clinical data have demonstrated that GLP-1 receptors are abundantly present in the heart and that stimulation of these receptors by GLP-1 has several effects. In this review, we will discuss the effects of GLP-1RA on heart rate, blood pressure, microvascular function, lipids, and inflammation, as measured in human mechanistic studies, and suggest how these effects may translate into the improved cardiovascular outcomes as demonstrated in several trials.

Effects of dipeptidyl peptidase-4 inhibitor linagliptin versus sulphonylurea glimepiride on systemic haemodynamics in overweight patients with type 2 diabetes: A secondary analysis of an 8-week, randomized, controlled, double-blind trial

AIM

To determine the glucose-independent effect of the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin versus the sulphonylurea glimepiride on systemic haemodynamics in the fasting and postprandial state in patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this prespecified secondary analysis of a phase IV, double-blind trial, 46 metformin-treated, overweight patients with T2D were included and randomly assigned (1:1) to once-daily linagliptin (5 mg) or glimepiride (1 mg) for 8 weeks. In a sub-study involving 26 patients, systemic haemodynamics were also assessed following a standardized liquid meal (Nutridrink Yoghurt style). Systemic haemodynamics (oscillometric device and finger photoplethysmography), arterial stiffness (applanation tonometry) and cardiac sympathovagal balance (heart rate variability [HRV]) were measured in the fasting state and repetitively following the meal. Ewing tests were performed in the fasting state.

RESULTS

From baseline to week 8, linagliptin compared with glimepiride did not affect systemic haemodynamics, arterial stiffness or HRV in the fasting state. Linagliptin increased parasympathetic nervous activity, as measured by the Valsalva manoeuvre (P = .021) and deep breathing test (P = .027) compared with glimepiride. Postprandially, systolic blood pressure (SBP) dropped an average of 7.6 ± 1.6 mmHg. Linagliptin reduced this decrease to 0.7 ± 2.3 mmHg, which was significant to glimepiride (P = .010).

CONCLUSIONS

When compared with glimepiride, linagliptin does not affect fasting blood pressure. However, linagliptin blunted the postprandial drop in SBP, which could benefit patients with postprandial hypotension.

Effects of Liraglutide Compared With Placebo on Events of Acute Gallbladder or Biliary Disease in Patients With Type 2 Diabetes at High Risk for Cardiovascular Events in the LEADER Randomized Trial

OBJECTIVE

To explore gallbladder- and biliary tract-related events reported for the liraglutide and placebo groups in the Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) trial.

RESEARCH DESIGN AND METHODS

LEADER was an international, randomized, double-blind, controlled cardiovascular (CV) outcomes trial. Participants with type 2 diabetes at high risk for CV events (n = 9,340) were randomized 1:1 to receive either liraglutide (≤1.8 mg daily; n = 4,668) or placebo (n = 4,672), with both groups also receiving standard care (treatment period: 3.5-5 years). Acute gallstone disease was a medical event of special interest. This post hoc analysis categorized captured events of acute gallbladder or biliary disease into four groups: uncomplicated gallbladder stones, complicated gallbladder stones, cholecystitis, and biliary obstruction. Time to first event by treatment group was analyzed using Cox regression.

RESULTS

There was an increased risk of acute gallbladder or biliary disease with liraglutide versus placebo (n = 141 of 4,668 vs. n = 88 of 4,672 patients, respectively; hazard ratio [HR] 1.60; 95% CI 1.23, 2.09; P < 0.001). Similar trends were observed for each of the four categories of gallbladder- or biliary tract-related events. Cholecystectomy was performed more frequently in liraglutide-treated patients (HR 1.56; 95% CI 1.10, 2.20; P = 0.013) but for similar proportions of the patients who experienced gallbladder- or biliary tract-related events (57% with liraglutide vs. 59% with placebo).

CONCLUSIONS

Although LEADER was not specifically designed to assess acute gallbladder or biliary disease, the trial showed an increased risk of gallbladder- or biliary tract-related events with liraglutide versus placebo, which appeared to be consistent across four categories of these events. Further studies should investigate the relevant mechanisms.

GLP-1 receptor agonists do not affect sodium intake: Exploratory analyses from two randomized clinical trials

OBJECTIVES

Excessive sodium intake, despite current dietary advice, remains a global issue with cardiovascular and renal consequences. The aim of this study was to determine whether glucagon-like peptide receptor agonists (GLP-1 RAs), used as antihyperglycemic agents for type 2 diabetes (T2DM) management, may reduce salt cravings as they are known to reduce hedonic feeding behavior and are involved in sodium homeostasis by increasing renal sodium excretion.

METHODS

We performed exploratory analyses using data from two randomized, clinical crossover trials, which primarily aimed to assess the effects of GLP-1 RAs on central satiety and reward circuits and subsequent related feeding behavior. In study A, healthy, obese individuals and patients with T2DM were randomly assigned to receive intravenous administration of placebo or GLP-1 RA exenatide with or without concurrent GLP-1 receptor blockade, on separate testing days. In study B, individuals with T2DM randomly received GLP-1 RA liraglutide (titrated up to 1.8 mg daily) or titrated insulin glargine for 12 wk. In both studies, participants received an ad libitum mixed meal that served to calculate sodium intake. Moreover, salt craving was scored using a Likert scale.

RESULTS

In study A, acute exenatide, parallel to reduced total food intake, reduced sodium intake in all studied groups by up to 30%. In study B, prolonged liraglutide treatment did not affect sodium or total caloric intake. Neither acute exenatide nor prolonged liraglutide treatment affected salt craving as measured by the Likert scale.

CONCLUSION

Acute exenatide reduced sodium intake in light of a generalized reduction in food ingestion, while prolonged intervention with liraglutide did not lower sodium intake. Neither intervention affected salt craving. Given the known effects of these drugs on renal sodium excretion, blood pressure, and renal and cardiovascular outcome, it seems plausible to perform dedicated mechanistic studies in humans to assess the effects of GLP-1 RA administration on sodium balance.

Understanding Bile Acid Signaling in Diabetes: From Pathophysiology to Therapeutic Targets

Diabetes and obesity have reached an epidemic status worldwide. Diabetes increases the risk for cardiovascular disease and non-alcoholic fatty liver disease. Primary bile acids are synthesized in hepatocytes and are transformed to secondary bile acids in the intestine by gut bacteria. Bile acids are nutrient sensors and metabolic integrators that regulate lipid, glucose, and energy homeostasis by activating nuclear farnesoid X receptor and membrane Takeda G protein-coupled receptor 5. Bile acids control gut bacteria overgrowth, species population, and protect the integrity of the intestinal barrier. Gut bacteria, in turn, control circulating bile acid composition and pool size. Dysregulation of bile acid homeostasis and dysbiosis causes diabetes and obesity. Targeting bile acid signaling and the gut microbiome have therapeutic potential for treating diabetes, obesity, and non-alcoholic fatty liver disease.

Bile Acids as Metabolic Regulators and Nutrient Sensors

Bile acids facilitate nutrient absorption and are endogenous ligands for nuclear receptors that regulate lipid and energy metabolism. The brain-gut-liver axis plays an essential role in maintaining overall glucose, bile acid, and immune homeostasis. Fasting and feeding transitions alter nutrient content in the gut, which influences bile acid composition and pool size. In turn, bile acid signaling controls lipid and glucose use and protection against inflammation. Altered bile acid metabolism resulting from gene mutations, high-fat diets, alcohol, or circadian disruption can contribute to cholestatic and inflammatory diseases, diabetes, and obesity. Bile acids and their derivatives are valuable therapeutic agents for treating these inflammatory metabolic diseases.

The incretin pathway as a therapeutic target in diabetic kidney disease: a clinical focus on GLP-1 receptor agonists

Diabetic kidney disease (DKD) remains the main cause for chronic kidney disease (CKD) and end-stage kidney disease (ESKD) worldwide. Both CKD and ESKD lead to major increases in risk of cardiovascular disease and death in people with diabetes. Despite optimal management of lifestyle, glucose levels and hypertension, residual risk remains high, indicating that additional therapies to mitigate the burden of the disease are desired. In past decades, new treatment options for the management of diabetes have emerged, of which some have showed promising renoprotective potential. This review discusses current understanding of the renal effects of glucagon-like peptide receptor agonists and their potential use in prevention and treatment of DKD.

Sodium butyrate reduces high-fat diet-induced non-alcoholic steatohepatitis through upregulation of hepatic GLP-1R expression

Glucagon-like peptide-1 (GLP-1) has a broad spectrum of biological activity by regulating metabolic processes via both the direct activation of the class B family of G protein-coupled receptors and indirect nonreceptor-mediated pathways. GLP-1 receptor (GLP-1R) agonists have significant therapeutic effects on non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) in animal models. However, clinical studies indicated that GLP-1 treatment had little effect on hepatic steatosis in some NAFLD patients, suggesting that GLP-1 resistance may occur in these patients. It is well-known that the gut metabolite sodium butyrate (NaB) could promote GLP-1 secretion from intestinal L cells. However, it is unclear whether NaB improves hepatic GLP-1 responsiveness in NAFLD. In the current study, we showed that the serum GLP-1 levels of NAFLD patients were similar to those of normal controls, but hepatic GLP-1R expression was significantly downregulated in NAFLD patients. Similarly, in the NAFLD mouse model, mice fed with a high-fat diet showed reduced hepatic GLP-1R expression, which was reversed by NaB treatment and accompanied by markedly alleviated liver steatosis. In addition, NaB treatment also upregulated the hepatic p-AMPK/p-ACC and insulin receptor/insulin receptor substrate-1 expression levels. Furthermore, NaB-enhanced GLP-1R expression in HepG2 cells by inhibiting histone deacetylase-2 independent of GPR43/GPR109a. These results indicate that NaB is able to prevent the progression of NAFL to NASH via promoting hepatic GLP-1R expression. NaB is a GLP-1 sensitizer and represents a potential therapeutic adjuvant to prevent NAFL progression to NASH.

SGLT2 Inhibitors in Combination Therapy: From Mechanisms to Clinical Considerations in Type 2 Diabetes Management

The progressive nature of type 2 diabetes (T2D) requires practitioners to periodically evaluate patients and intensify glucose-lowering treatment once glycemic targets are not attained. With guidelines moving away from a one-size-fits-all approach toward setting patient-centered goals and allowing flexibility in choosing a second-/third-line drug from the growing number of U.S. Food and Drug Administration-approved glucose-lowering agents, keen personalized management in T2D has become a challenge for health care providers in daily practice. Among the newer generation of glucose-lowering drug classes, sodium-glucose cotransporter 2 inhibitors (SGLT2is), which enhance urinary glucose excretion to lower hyperglycemia, have made an imposing entrance to the T2D treatment armamentarium. Given their unique insulin-independent mode of action and their favorable efficacy-to-adverse event profile and given their marked benefits on cardiovascular-renal outcome in moderate-to-high risk T2D patients, which led to updates of guidelines and product monographs, the role of this drug class in multidrug regimes is promising. However, despite many speculations based on pharmacokinetic and pharmacodynamic properties, physiological reasoning, and potential synergism, the effects of these agents in terms of glycemic and pleiotropic efficacy when combined with other glucose-lowering drug classes are largely understudied. In this perspective, we review the currently emerging evidence, discuss prevailing hypotheses, and elaborate on necessary future studies to clarify the potential risks and benefits of using an SGLT2i in dual combination with metformin and triple combination with a glucagon-like peptide 1 receptor agonist, dipeptidyl peptidase 4 inhibitor, or other glucose-lowering agent that is recommended by the American Diabetes Association and European Association for the Study of Diabetes (i.e., a sulfonylurea, thiazolidinedione, or insulin) to treat patients with T2D.

Gastric mucosal devitalization reduces adiposity and improves lipid and glucose metabolism in obese rats

BACKGROUND AND AIMS

The gastric mucosa is an endocrine organ that regulates satiation pathways by expression of orexigenic and anorexigenic hormones. Vertical sleeve gastrectomy (VSG) excludes gastric mucosa and reduces gastric volume. Our study aimed to investigate the independent effects of altering gastric mucosa on obesity and its related comorbidities.

METHODS

Gastric mucosa devitalization (GMD) of 70% of the stomach was achieved by argon plasma coagulation in a high-fat diet rat model and was compared with VSG and sham surgery. In an 8-week follow-up study, we quantified body weight, visceral adiposity, insulin resistance index, cholesterol profiles, and free fatty acid profiles by enzyme-linked immunosorbent assay (ELISA). Following a 2-hour oral glucose tolerance test, the kinetics of ghrelin, glucagon-like peptide-1, peptide YY, and serum and liver bile acid levels were measured. Liver lipid content was quantified by ELISA.

RESULTS

GMD resulted in significant reductions in body weight, visceral and subcutaneous adipose tissue, and hepatic steatosis as well as an improvement in lipid metabolism. GMD resulted in significant reductions in food intake and intestinal malabsorption of free fatty acids, both contributing to improved body composition and metabolic profile. Mechanistically, GMD resulted in a significant reduction in serum palmitate levels as well as an increase in serum and liver bile acid levels, known to alter glucose and lipid metabolism. Similar changes were noted when VSG rats were compared with sham surgery rats.

CONCLUSIONS

Devitalization of gastric mucosa, independent of altering gastric volume, was able to reduce obesity-related comorbidities. The gastric mucosa may be a potential target for treating obesity and its associated comorbidities.

Exendin-4, a glucagon-like peptide-1 analogue accelerates healing of chronic gastric ulcer in diabetic rats

Background

Diabetes mellitus is an independent risk factor for impaired healing of peptic ulcers, and there are currently no supplementary therapeutics other than the standard antipeptic medicine to improve the ulcer healing in diabetes. This study examined the potential pleiotropic effect of a glucagon-like peptide (Glp)-1 analogue exendin (Ex)-4 on the regeneration of gastric ulcer in streptozotocin-induced diabetic rats.

Methods and results

Chronic ulcer was created in rat stomach by submucosal injection of acetic acid and peri-ulcer tissues were analyzed 7 days after operation. Ulcer wound healing was impaired in diabetic rats with suppressed tissue expression of eNOS and enhanced levels of pro-inflammatory reactions. Treatment with intraperitoneal injection of Ex4 (0.5 μg/kg/d) significantly reduced the area of gastric ulcer without changing blood glucose level. Ex-4 restored the expression of pro-angiogenic factors, and attenuated the generation of regional inflammation and superoxide anions. The improvement of ulcer healing was associated with increased expression of MMP-2 and formation of granulation tissue in the peri-ulcer area.

Conclusion

Administration of Ex4 may induce pro-angiogenic, anti-inflammatory and anti-oxidative reactions in the peri-ulcer tissue of diabetic rats that eventually enhances tissue granulation and closure of ulcerative wounds. Our results support the potential clinical application of Glp-1 analogues as supplementary hypoglycemic agents in the antipeptic ulcer medication in diabetes.

GLP-1 and the kidney: from physiology to pharmacology and outcomes in diabetes

The gastrointestinal tract - the largest endocrine network in human physiology - orchestrates signals from the external environment to maintain neural and hormonal control of homeostasis. Advances in understanding entero-endocrine cell biology in health and disease have important translational relevance. The gut-derived incretin hormone glucagon-like peptide 1 (GLP-1) is secreted upon meal ingestion and controls glucose metabolism by modulating pancreatic islet cell function, food intake and gastrointestinal motility, amongst other effects. The observation that the insulinotropic actions of GLP-1 are reduced in type 2 diabetes mellitus (T2DM) led to the development of incretin-based therapies - GLP-1 receptor agonists and dipeptidyl peptidase 4 (DPP-4) inhibitors - for the treatment of hyperglycaemia in these patients. Considerable interest exists in identifying effects of these drugs beyond glucose-lowering, possibly resulting in improved macrovascular and microvascular outcomes, including in diabetic kidney disease. As GLP-1 has been implicated as a mediator in the putative gut-renal axis (a rapid-acting feed-forward loop that regulates postprandial fluid and electrolyte homeostasis), direct actions on the kidney have been proposed. Here, we review the role of GLP-1 and the actions of associated therapies on glucose metabolism, the gut-renal axis, classical renal risk factors, and renal end points in randomized controlled trials of GLP-1 receptor agonists and DPP-4 inhibitors in patients with T2DM.

Roles of the gut in the metabolic syndrome: an overview

The metabolic syndrome is a cluster of risk factors (central obesity, hyperglycaemia, dyslipidaemia and arterial hypertension), indicating an increased risk of diabetes, cardiovascular disease and premature mortality. The gastrointestinal tract is seldom discussed as an organ system of principal importance for metabolic diseases. The present overview connects various metabolic research lines into an integrative physiological context in which the gastrointestinal tract is included. Strong evidence for the involvement of the gut in the metabolic syndrome derives from the powerful effects of weight-reducing (bariatric) gastrointestinal surgery. In fact, gastrointestinal surgery is now recommended as a standard treatment option for type 2 diabetes in obesity. Several gut-related mechanisms that potentially contribute to the metabolic syndrome will be presented. Obesity can be caused by hampered release of satiety-signalling gut hormones, reduced meal-associated energy expenditure and microbiota-assisted harvest of energy from nondigestible food ingredients. Adiposity per se is a well-established risk factor for hyperglycaemia. In addition, a leaky gut mucosa can trigger systemic inflammation mediating peripheral insulin resistance that together with a blunted incretin response aggravates the hyperglycaemic state. The intestinal microbiota is strongly associated with obesity and the related metabolic disease states, although the mechanisms involved remain unclear. Enterorenal signalling has been suggested to be involved in the pathophysiology of hypertension and postprandial triglyceride-rich chylomicrons; in addition, intestinal cholesterol metabolism probably contributes to atherosclerosis. It is likely that in the future, the metabolic syndrome will be treated according to novel pharmacological principles interfering with gastrointestinal functionality.

Pancreatic Effects of Liraglutide or Sitagliptin in Overweight Patients With Type 2 Diabetes: A 12-Week Randomized, Placebo-Controlled Trial

OBJECTIVE

To assess the mechanistic effects of the glucagon-like peptide 1 (GLP-1) receptor agonist liraglutide and the dipeptidyl peptidase 4 (DPP-4) inhibitor sitagliptin on (exocrine) pancreatic physiology and morphology.

RESEARCH DESIGN AND METHODS

For this randomized, double-blind, parallel-group trial, 55 patients with type 2 diabetes treated with metformin and/or sulfonylurea agents were included. Participants received liraglutide 1.8 mg (n = 19), sitagliptin 100 mg (n = 19), or matching placebos (n = 17) once daily for 12 weeks. The primary end point was change in exocrine function (intraduodenal pancreatic fluid secretion, lipase activity, fecal elastase-1, and chymotrypsin). Secondary end points included changes in plasma enzyme concentrations and pancreatic morphology (per MRI).

RESULTS

No patient developed pancreatitis. Sitagliptin increased intraduodenal pancreatic fluid secretion by 16.3 mL (95% CI -0.3 to 32.9; P = 0.05), whereas liraglutide did not change exocrine pancreatic function. Neither therapy increased lipase/amylase levels after 12 weeks. However, liraglutide increased lipase levels after 6 weeks (23.5 U/L [95% CI 2.1-44.8]; P = 0.03) and sitagliptin increased amylase levels after 2 and 6 weeks (13.7 U/L [95% CI 3.4-23.9]; P = 0.03). Both drugs increased plasma trypsinogen after 12 weeks (liraglutide: 34.6 µg/mL [95% CI 15.1-54.2], P = 0.001; sitagliptin: 23.9 µg/mL [95% CI 4.9-42.9], P = 0.01). Neither changed pancreatic morphology, although liraglutide tended to increase pancreatic volume (7.7 cm³ [95% CI -1.2 to 16.6]; P = 0.09). Treatment-induced volume expansion was associated with increased amylase levels.

CONCLUSIONS

A 12-week treatment with liraglutide or sitagliptin only resulted in a brief and modest increase of plasma pancreatic enzyme concentrations in patients with type 2 diabetes. Apart from a minimal sitagliptin-induced increase in intraduodenal fluid secretion, pancreatic exocrine function was unaffected. The long-term clinical consequences of these discrete changes require further study.

The effects of GLP-1 based therapies on postprandial haemodynamics: Two randomised, placebo-controlled trials in overweight type 2 diabetes patients

AIMS

To assess the effects of glucagon-like peptide (GLP)-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors on postprandial haemodynamics.

METHODS

57 patients with type 2 diabetes (mean±SD age 62.8±6.9years; BMI 31.8±4.1kg/m²; HbA_1c 7.3±0.6%) were included in an acute (exenatide- or placebo-infusion) and 12-week (liraglutide, sitagliptin or placebo) randomised, placebo-controlled, double-blind trial. Systemic haemodynamics (oscillometric technique and finger photoplethysmography), vascular stiffness (tonometry), and sympathetic nervous system (SNS)-activity (heart rate variability) were determined in the fasting state and following a standardised mixed meal.

RESULTS

In both studies, postprandial blood pressure (BP) decreased during placebo-intervention. Compared with placebo, acute exenatide-infusion increased postprandial diastolic BP (6.7 [95%-confidence interval 3.6-9.9]mmHg, p<0.001) and vascular resistance (683.6 [438.5-928.8]dyn*s/cm⁵/1.73m², p<0.001), while cardiac index decreased (0.6 [0.40.8]L/min/1.73m²; p<0.001). Systolic BP, augmentation index and SNS-activity were unaffected. Twelve-week liraglutide-treatment did not affect postprandial haemodynamics, while sitagliptin decreased diastolic BP (3.5 [0.0-6.9] mmHg; p=0.050), vascular resistance (309.9 [66.6-553.1]dyn*s/cm⁵/1.73m²; p=0.013) and cardiac index (0.3 [0.0-0.6]L/min/1.73m²; p=0.040), compared with placebo. Neither liraglutide nor sitagliptin affected SNS-activity or augmentation index. All treatments significantly lowered postprandial glucose levels.

CONCLUSIONS

Acute exenatide-infusion prevented the meal-induced decline in diastolic BP, although prolonged liraglutide intervention did not affect postprandial haemodynamics. The meal-induced drop in BP was augmented during sitagliptin-treatment.

The Role of Gut-brain Axis in Regulating Glucose Metabolism After Acute Pancreatitis

Objectives:

Diabetes has become an epidemic in developed and developing countries alike, with an increased demand for new efficacious treatments. A large body of pre-clinical evidence suggests that the gut–brain axis may be exploited as a potential therapeutic target for defective glucose homeostasis. This clinical study aimed to investigate a comprehensive panel of glucoregulatory peptides, released by both the gut and brain, in individuals after acute pancreatitis.

Methods:

Fasting levels of glucagon-like peptide-1 (GLP-1), glicentin, oxyntomodulin, peptide YY, ghrelin, cholecystokinin, vasoactive intestinal peptide (VIP), and secretin were studied. Modified Poisson and multivariable linear regression analyses were conducted. Pre-determined concentration ranges were used to categorize each peptide into quartiles.

Results:

A total of 83 individuals were included, of who 30 (36%) developed abnormal glucose metabolism (AGM) after acute pancreatitis. In individuals with AGM, the highest quartile of oxyntomodulin differed most significantly from the lowest quartile with a prevalence ratio (PR; 95% confidence interval) of 0.50 (0.21, 1.20; P=0.005); of glicentin with a PR of 0.26 (0.13, 0.54; P<0.001); and of VIP with a PR of 0.34 (0.13, 0.89; P=0.043). Peptide YY, GLP-1, cholecystokinin, ghrelin, and secretin were not significantly associated with AGM.

Conclusions:

Fasting circulating oxyntomodulin, glicentin, and VIP levels are significantly decreased in patients with defective glucose homeostasis after acute pancreatitis. Oxyntomodulin appears to be a promising therapeutic target for future clinical studies on diabetes associated with diseases of the exocrine pancreas.

Heart rate acceleration with GLP-1 receptor agonists in type 2 diabetes patients: an acute and 12-week randomised, double-blind, placebo-controlled trial

OBJECTIVE

To examine mechanisms underlying resting heart rate (RHR) increments of GLP-1 receptor agonists in type 2 diabetes patients.

DESIGN

Acute and 12-week randomised, placebo-controlled, double-blind, single-centre, parallel-group trial.

METHODS

In total, 57 type 2 diabetes patients (mean ± s.d. age: 62.8 ± 6.9 years; BMI: 31.8 ± 4.1 kg/m²; HbA1c: 7.3 ± 0.6%), treated with metformin and/or sulfonylureas, were included between July 2013 and August 2015. In the acute study, the GLP-1 receptor agonist exenatide (n = 29) or placebo (saline 0.9%; n = 28) was infused intravenously. Subsequently, patients were again randomised to receive the GLP-1 receptor agonist liraglutide (n = 19) or matching placebo (n = 17) for 12 weeks. RHR and blood pressure (BP) were measured by oscillometric technique, systemic haemodynamics by finger photoplethysmography, sympathetic nervous system (SNS) activity by heart rate variability and arterial stiffness by applanation tonometry. This trial was registered at ClinicalTrials.gov (Nbib1744236).

RESULTS

Exenatide-infusion increased RHR (mean ± s.e.m. +7.5 ± 0.9 BPM, P < 0.001), and systolic and diastolic BP (both P < 0.05), compared with placebo. Vascular resistance increased during exenatide-infusion, whereas stroke volume and arterial stiffness decreased (P < 0.05). SNS activity and cardiac output were unaffected. Twelve-week treatment with liraglutide increased RHR (+6.6 ± 2.1 BPM), while reducing systolic BP (-12.6 ± 4.7 mmHg) and stroke volume (all P < 0.01). Cardiac output, vascular resistance, arterial stiffness and SNS activity remained unchanged (all P > 0.05).

CONCLUSIONS

RHR acceleration with acute and 12-week GLP-1 receptor agonist treatment in type 2 diabetes patients is not explained by changes in SNS activity, and our data argue against vasodilation. In line with pre-clinical data, direct sino-atrial stimulation may be involved.

Biliary effects of liraglutide and sitagliptin, a 12-week randomized placebo-controlled trial in type 2 diabetes patients

AIMS

Treatment with glucagon-like peptide (GLP)-1 receptor agonists or dipeptidyl peptidase (DPP)-4 inhibitors might increase gallstone formation; however, the mechanisms involved are unknown. We aimed to assess the effects of these drugs on gallbladder volume and bile acid profile.

MATERIALS AND METHODS

A total of 57 type 2 diabetes patients (mean ± SD age, 62.8 ± 6.9 years; BMI, 31.8 ± 4.1 kg/m² ; HbA1c, 7.3% ± 0.6%), treated with metformin and/or sulfonylureas, were included in this 12-week randomized, placebo-controlled, double-blind, single-centre trial between July 2013 and August 2015 at the VU University Medical Center, the Netherlands. Patients received the GLP-1 receptor agonist liraglutide, the DPP-4 inhibitor sitagliptin or matching placebo for 12 weeks. Gallbladder fasting volume and ejection fraction were measured using ultrasonography after a high-fat meal. Serum bile acids were measured in the fasting and postprandial state and in faecal samples. The trial was registered at ClinicalTrials.gov (NCT01744236).

RESULTS

Neither liraglutide nor sitagliptin had an effect on gallbladder fasting volume and ejection fraction (p > .05). Liraglutide increased serum levels of deoxycholic acid in the fasting state [0.20 µmol/L (95% CI 0.027-0.376), p = 0.024] and postprandial state [AUC 40.71 (13.22-68.21), p = 0.005] and in faeces [ratio 1.5 (1.03-2.19); p = 0.035]. Sitagliptin had no effect on serum bile acids, but increased faecal levels of chenodeoxycholic acid [ratio 3.42 (1.33-8.79), p = 0.012], cholic acid [ratio 3.32 (1.26-8.87), p = 0.017] and ursodeoxycholic acid [ratio 3.81 (1.44-10.14), p = 0.008].

CONCLUSIONS

Neither liraglutide nor sitagliptin has an effect on gallbladder volume. Observed changes in bile acids with liraglutide suggest alterations in the intestinal microbiome, while sitagliptin appears to increase hepatic bile acid production.

Twelve week liraglutide or sitagliptin does not affect hepatic fat in type 2 diabetes: a randomised placebo-controlled trial

AIMS/HYPOTHESIS

Glucagon-like peptide (GLP)-1-based therapies have been suggested to improve hepatic steatosis. We assessed the effects of the GLP-1 receptor agonist liraglutide and the dipeptidyl peptidase (DPP)-4 inhibitor sitagliptin on hepatic steatosis and fibrosis in patients with type 2 diabetes.

METHODS

In this 12 week, parallel, randomised, placebo-controlled trial, performed at the VU University Medical Center between July 2013 and August 2015, 52 overweight patients with type 2 diabetes treated with metformin and/or sulphonylurea agent ([mean ± SD] age 62.7 ± 6.9 years, HbA_1c 7.3 ± 0.7% or 56 ± 1 mmol/mol) were allocated to once daily liraglutide 1.8 mg (n = 17), sitagliptin 100 mg (n = 18) or matching placebos (n = 17) by computer generated numbers. Both participants and researchers were blinded to group assignment. Hepatic fat content was measured using proton magnetic resonance spectroscopy (¹H-MRS). Hepatic fibrosis was estimated using three validated formulae.

RESULTS

One patient dropped out in the sitagliptin group owing to dizziness, but no serious adverse events occurred. At week 12, no between-group differences in hepatic steatosis were found. Liraglutide reduced steatosis by 10% (20.9 ± 3.4% to 18.8 ± 3.3%), sitagliptin reduced steatosis by 12.1% (23.9 ± 3.0% to 21.0 ± 2.7%) and placebo lessened it by 9.5% (18.7 ± 2.7% to 16.9 ± 2.7%). Neither drug affected hepatic fibrosis scores compared with placebo.

CONCLUSIONS/INTERPRETATION

Twelve-week liraglutide or sitagliptin treatment does not reduce hepatic steatosis or fibrosis in type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01744236 FUNDING : Funded by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 282521 - the SAFEGUARD project.

GLP-1–Based Therapies Have No Microvascular Effects in Type 2 Diabetes Mellitus

Objective—

To assess the effects of glucagon-like peptide (GLP)-1–based therapies (ie, GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) on microvascular function in patients with type 2 diabetes mellitus.

Approach and Results—

We studied 57 patients with type 2 diabetes mellitus (mean±SD age: 62.8±6.9 years; body mass index: 31.8±4.1 kg/m 2 ; HbA 1c [glycated hemoglobin] 7.3±0.6%) in an acute and 12-week randomized, placebo-controlled, double-blind trial conducted at the Diabetes Center of the VU University Medical Center. In the acute study, the GLP-1 receptor agonist exenatide (therapeutic concentrations) or placebo (saline 0.9%) was administered intravenously. During the 12-week study, patients received the GLP-1 receptor agonist liraglutide (1.8 mg daily), the dipeptidyl peptidase-4 inhibitor sitagliptin (100 mg daily), or matching placebos. Capillary perfusion was assessed by nailfold skin capillary videomicroscopy and vasomotion by laser Doppler fluxmetry, in the fasting state and after a high-fat mixed meal. In neither study, treatment affected fasting or postprandial capillary perfusion compared with placebo ( P >0.05). In the fasting state, acute exenatide infusion increased neurogenic vasomotion domain power, while reducing myogenic domain power (both P <0.05). After the meal, exenatide increased endothelial domain power ( P <0.05). In the 12-week study, no effects on vasomotion were observed.

Conclusions—

Despite modest changes in vasomotion, suggestive of sympathetic nervous system activation and improved endothelial function, acute exenatide infusion does not affect skin capillary perfusion in type 2 diabetes mellitus. Twelve-week treatment with liraglutide or sitagliptin has no effect on capillary perfusion or vasomotion in these patients. Our data suggest that the effects of GLP-1–based therapies on glucose are not mediated through microvascular responses.