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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., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

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., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are well-established glucose-lowering drugs for type 2 diabetes mellitus (T2DM) management. Acute GLP-1RA administration increases urinary excretion of sodium and other electrolytes. However, the renal tubular effects of prolonged GLP-1RA treatment are largely unknown. In this secondary analysis of a randomized trial, we determined the renal tubular effects of 8-wk treatment with 20 μg lixisenatide, a short-acting (prandial) GLP-1RA, versus titrated once-daily insulin glulisine in 35 overweight T2DM-patients on stable insulin glargine background therapy (age: 62 ± 7 yr, glycated hemoglobin: 8.0 ± 0.9%, estimated glomerular filtration rate: >60 ml·min -1 ·1.73 m -2 ). After a standardized breakfast, lixisenatide increased absolute and fractional excretions of sodium, chloride, and potassium and increased urinary pH. In contrast, lixisenatide reduced absolute and fractional excretions of magnesium, calcium, and phosphate. At week 8, patients treated with lixisenatide had significantly more phosphorylated sodium-hydrogen exchanger isoform 3 (NHE3) in urinary extracellular vesicles than those on insulin glulisine treatment, which suggested decreased NHE3 activity in the proximal tubule. A rise in postprandial blood pressure with lixisenatide partly explained the changes in the urinary excretion of sodium, potassium, magnesium, and phosphate and the changes in urinary pH. In conclusion, lixisenatide affects postprandial urinary excretion of several electrolytes and increases urinary pH compared with insulin glulisine in T2DM patients after 8 wk of treatment. This is most likely explained by a drug-induced rise in blood pressure or direct inhibitory effects on NHE3 in the proximal tubule.

Aims: To determine the effects of glucagon-like peptide (GLP)-1 receptor agonists (RA) on uric acid (UA) levels and kidney UA clearance., Material and Methods: This study involved post-hoc analyses of 4 controlled clinical trials, which assessed actions of GLP-1RA administration on kidney physiology. The immediate effects of GLP-1RA exenatide infusion vs placebo were determined in 9 healthy overweight men (Study-A) and in 52 overweight T2DM patients (Study-B). The effects of 12 weeks of long-acting GLP-1RA liraglutide vs placebo in 36 overweight T2DM patients (Study-C) and of 8 weeks of short-acting GLP-1RA lixisenatide vs once-daily titrated insulin glulisine in 35 overweight T2DM patients (Study-D) were also examined. Plasma UA, fractional (inulin-corrected) and absolute urinary excretion of UA (UE UA ) and sodium (UE Na ), and urine pH were determined., Results: Median baseline plasma UA level was 5.39 to 6.33 mg/dL across all studies (17%-22% of subjects were hyperuricaemic). In Study-A, exenatide infusion slightly increased plasma UA (+0.07 ± 0.02 mg/dL, P = .04), and raised absolute-UE UA (+1.58 ± 0.65 mg/min/1.73 m 2 , P = .02), but did not affect fractional UE UA compared to placebo. Fractional UE UA and absolute UE UA correlated with increases in urine pH (r:0.86, P = .003 and r:0.92, P < .001, respectively). Fractional UE UA correlated with increased fractional UE Na (r:0.76, P = .02). In Study-B, exenatide infusion did not affect plasma UA, but increased fractional UE UA (+0.76 ± 0.38%, P = .049) and absolute UE UA (+0.75 ± 0.27 mg/min/1.73 m 2 , P = .007), compared to placebo. In regression analyses, both parameters were explained by changes in urine pH and, in part, by changes in UE Na . In Study-C, liraglutide treatment did not affect plasma UA, UE UA, UE Na or urine pH, compared to placebo. In Study-D, lixisenatide treatment increased UE Na and urine pH from baseline, but did not affect plasma UA or UE UA ., Conclusion: Immediate exenatide infusion increases UE UA in overweight healthy men and in T2DM patients, probably by inhibiting Na + /H + -exchanger type-3 in the renal proximal tubule. Prolonged treatment with a long-acting or short-acting GLP-1RA does not affect plasma UA or UE UA in T2DM patients with normal plasma UA levels and at relatively low cardiovascular risk. Our results suggest that the cardio-renal benefits of GLP-1RA are not mediated through changes in UA., (© 2018 John Wiley & Sons Ltd.)

Aim: To determine whether lixisenatide, a prandial short-acting glucagon-like peptide receptor agonist (GLP-1RA), ameliorates postprandial glomerular hyperfiltration in patients with type 2 diabetes mellitus (T2DM) compared with insulin-glulisine (iGlu)., Methods: Postprandial renal haemodynamic effects of 8-week treatment with lixisenatide 20 µg vs once-daily titrated iGlu were measured in 35 overweight patients with T2DM inadequately controlled on insulin-glargine, with or without metformin [mean ± SD age 62 ± 7 years, HbA1c 8.0% ± 0.9%, estimated glomerular filtration rate (GFR) 85 ± 12 mL/min/1.73 m 2 , median (IQR) urinary albumin/creatinine ratio 1.5 (0.9-3.0) mg/mmol]. After a standardised breakfast, GFR (primary endpoint) and effective renal plasma flow (ERPF) were determined by inulin and para-aminohippuric acid renal clearance, respectively, based on timed urine sampling. Intrarenal haemodynamic functions were estimated using Gomez equations., Results: Compared with iGlu, lixisenatide did not affect GFR [+0.1 mL/min/1.73 m 2 (95% CI -9 to 9)], ERPF [-17 mL/min/1.73 m 2 (-61 to 26)], other (intra-)renal haemodynamics or renal damage markers, but increased fractional sodium excretion [+0.25% (0.09-0.41)] and urinary pH [+0.7 (0.3-1.2)]. Plasma renin, angiotensin-II and aldosterone were unchanged. Lixisenatide and iGlu reduced HbA1c similarly, by 0.8% ± 0.1% and 0.6% ± 0.1%, respectively, while postprandial glucose was lower with lixisenatide (P = .002). Compared with iGlu, lixisenatide reduced bodyweight [-1.4 kg (-2.5 to -0.2)] and increased postprandial mean arterial pressure [+9 mm Hg (4-14)]., Conclusion: Eight-week lixisenatide treatment does not affect postprandial (intra-)renal haemodynamics compared with iGlu when added to insulin-glargine in patients with T2DM without overt nephropathy. Prolonged lixisenatide treatment has a sustained natriuretic effect, which is in contrast to previous reports on long-acting GLP-1RA, reduces body weight and increases postprandial blood pressure compared with iGlu., Trial Registration: ClinicalTrials.gov identifier NCT02276196., (© 2017 John Wiley & Sons Ltd.)

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/m 2 ; 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., (© 2017 European Society of Endocrinology.)

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); HbA1c [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., (© 2016 American Heart Association, Inc.)

Aims/hypothesis: This study aimed to investigate the acute renal effects of the glucagon-like peptide-1 receptor agonist (GLP-1RA) exenatide in type 2 diabetes patients., Methods: We included overweight (BMI 25-40 kg/m(2)) men and postmenopausal women, aged 35-75 years with type 2 diabetes (HbA1c 48-75 mmol/mol; 6.5-9.0%) and estimated GFR ≥ 60 ml min(-1) 1.73 m(-2). Exenatide or placebo (NaCl solution, 154 mmol/l) was administrated intravenously in an acute, randomised, double-blind, placebo-controlled trial conducted at the Diabetes Center VU University Medical Center (VUMC). GFR (primary endpoint) and effective renal plasma flow (ERPF) were determined by inulin and para-aminohippurate clearance, respectively, based on timed urine sampling. Filtration fraction (FF) and effective renal vascular resistance (ERVR) were calculated, and glomerular hydrostatic pressure (PGLO) and vascular resistance of the afferent (RA) and efferent (RE) renal arteriole were estimated. Tubular function was assessed by absolute and fractional excretion of sodium (FENa), potassium (FEK) and urea (FEU), in addition to urine osmolality, pH and free water clearance. Renal damage markers, BP and plasma glucose were also determined., Results: Of the 57 patients randomised by computer, 52 were included in the final analyses. Exenatide (n = 24) did not affect GFR (mean difference +2 ± 3 ml min(-1) 1.73 m(-2), p = 0.489), ERPF, FF, ERVR or PGLO, compared with placebo (n = 28). Exenatide increased RA (p < 0.05), but did not change RE. Exenatide increased FENa, FEK, urine osmolality and pH, while FEU, urinary flow and free water clearance were decreased (all p < 0.05). Osmolar clearance and renal damage makers were not affected. Diastolic BP and mean arterial pressure increased by 3 ± 1 and 6 ± 2 mmHg, respectively, whereas plasma glucose decreased by 1.4 ± 0.1 mmol/l (all p < 0.05)., Conclusions/interpretation: Exenatide infusion does not acutely affect renal haemodynamics in overweight type 2 diabetes patients at normal filtration levels. Furthermore, acute GLP-1RA administration increases proximal sodium excretion in these patients., Trial Registration: ClincialTrials.gov NCT01744236 FUNDING : The research leading to these results has been funded from: (1) the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement number 282521 - the SAFEGUARD project; and (2) the Dutch Kidney Foundation, under grant agreement IP12.87.

Background: Sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) lower blood pressure (BP). When SGLT2i and GLP-1RA are combined, synergistic effects on BP have been observed. The mechanisms underlying these BP reductions are incompletely understood. The aim of this study was to assess the mechanisms underlying the BP reduction with the SGLT2i dapagliflozin, GLP-1RA exenatide, and dapagliflozin-exenatide compared with placebo in people with obesity and type 2 diabetes. Methods: Sixty-six people with type 2 diabetes were randomized to 16 weeks of dapagliflozin 10 mg/day, exenatide 10 µg twice daily, dapagliflozin-exenatide, or placebo treatment. The effect of treatments on estimates of: (1) plasma volume (calculated by Strauss formula, bioimpedance spectroscopy, hematocrit, (2) autonomic nervous system activity (heart rate variability), (3) arterial stiffness (pulse wave applanometry), (4) systemic hemodynamic parameters including peripheral vascular resistance, cardiac output and stroke volume (all derived from non-invasively systemic hemodynamic monitoring), and (5) natriuresis (24-hour urine collection) were assessed after 10 days and 16 weeks of treatment. Results: After 10 days, dapagliflozin reduced systolic BP (SBP) by − 4.7 mmHg, and reduced plasma volume. After 16 weeks, dapagliflozin reduced SBP by − 4.4 mmHg, and reduced sympathetic nervous system (SNS) activity. Exenatide had no effect on SBP, but reduced parasympathetic nervous system activity after 10 days and 16 weeks. After 10 days, dapagliflozin-exenatide reduced SBP by − 4.2 mmHg, and reduced plasma volume. After 16 weeks, dapagliflozin-exenatide reduced SBP by − 6.8 mmHg, and the reduction in plasma volume was still observed, but SNS activity was unaffected. Conclusions: The dapagliflozin-induced plasma volume contraction may contribute to the initial SBP reduction, while a reduction in SNS activity may contribute to the persistent SBP reduction. Dapagliflozin-exenatide resulted in the largest decrease in SBP. The effect on plasma volume was comparable to dapagliflozin monotherapy, and SNS activity was not reduced, therefore other mechanisms are likely to contribute to the blood pressure lowering effect of this combination, which need further investigation. Trial registration Clinicaltrials.gov, NCT03361098. [ABSTRACT FROM AUTHOR]

The glucagon-like peptide-1 receptor agonist (GLP-1RA) semaglutide is the most recently approved agent of this drug class, and the only GLP-1RA currently available as both subcutaneous and oral formulation. While GLP-1RAs effectively improve glycemic control and cause weight loss, potential safety concerns have arisen over the years. For semaglutide, such concerns have been addressed in the extensive phase 3 registration trials including cardiovascular outcome trials for both subcutaneous (SUSTAIN: Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes) and oral (PIONEER: Peptide InnOvatioN for the Early diabEtes tReatment) semaglutide and are being studied in further trials and registries, including real world data studies. In the current review we discuss the occurrence of adverse events associated with semaglutide focusing on hypoglycemia, gastrointestinal side effects, pancreatic safety (pancreatitis and pancreatic cancer), thyroid cancer, gallbladder events, cardiovascular aspects, acute kidney injury, diabetic retinopathy (DRP) complications and injection-site and allergic reactions and where available, we highlight potential underlying mechanisms. Furthermore, we discuss whether effects are specific for semaglutide or a class effect. We conclude that semaglutide induces mostly mild-to-moderate and transient gastrointestinal disturbances and increases the risk of biliary disease (cholelithiasis). No unexpected safety issues have arisen to date, and the established safety profile for semaglutide is similar to that of other GLP-1RAs where definitive conclusions for pancreatic and thyroid cancer cannot be drawn at this point due to low incidence of these conditions. Due to its potent glucose-lowering effect, patients at risk for deterioration of existing DRP should be carefully monitored if treated with semaglutide, particularly if also treated with insulin. Given the beneficial metabolic and cardiovascular actions of semaglutide, and the low risk for severe adverse events, semaglutide has an overall favorable risk/benefit profile for patient with type 2 diabetes. [ABSTRACT FROM AUTHOR]

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 ( 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. [ABSTRACT FROM AUTHOR]

Objective: To investigate effects of dipeptidyl peptidase-4 inhibitor (DPP-4I) sitagliptin or glucagon-like peptide 1 (GLP-1) receptor agonist liraglutide treatment on renal hemodynamics, tubular functions, and markers of renal damage in overweight patients with type 2 diabetes without chronic kidney disease (CKD).Research Design and Methods: In this 12-week, randomized, double-blind trial, 55 insulin-naïve patients with type 2 diabetes (mean ± SEM: age 63 ± 7 years, BMI 31.8 ± 4.1 kg/m2, glomerular filtration rate [GFR] 83 ± 16 mL/min/1.73 m2; median [interquartile range]: albumin-to-creatinine ratio (ACR) 1.09 mg/mmol [0.47-3.31]) received sitagliptin (100 mg/day), liraglutide (1.8 mg/day), or matching placebos. GFR (primary end point) and effective renal plasma flow (ERPF) were determined by inulin and para-aminohippuric acid clearance, respectively. Intrarenal hemodynamic variables were estimated. Absolute and fractional excretions of sodium (FENa), potassium, and urea (FEU) and renal damage markers (ACR, neutrophil gelatinase-associated lipocalin [NGAL], and kidney injury molecule-1 [KIM-1]) were measured. Plasma renin concentration (PRC) and glycated hemoglobin (HbA1c) were assessed. At weeks 2 and 6, estimated GFR and fractional electrolyte excretions were determined.Results: At week 12, GFR was not affected by sitagliptin (-6 mL/min/1.73 m2 [95% CI -14 to 3], P = 0.17) or liraglutide (+3 mL/min/1.73 m2 [-5 to 11], P = 0.46), compared with placebo. Sitagliptin modestly reduced estimated glomerular hydraulic pressure (PGLO; P = 0.043). ERPF, other intrarenal hemodynamic variables, renal damage markers, and PRC did not change for both treatments. Both agents reduced HbA1c. Only at week 2, sitagliptin increased FENa and FEU (P = 0.005).Conclusions: Twelve-week treatment with sitagliptin or liraglutide does not affect measured renal hemodynamics. No sustained changes in tubular functions or alteration in renal damage markers were observed. The validity and clinical relevance of the slight sitagliptin-induced PGLO reduction remains speculative. [ABSTRACT FROM AUTHOR]