Incretin therapies: highlighting common features and differences in the modes of action of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors

Rationale for and Design of the Study of Early Enteral Dextrose in Sepsis: A Pilot Placebo-Controlled Randomized Clinical Trial

BACKGROUND

Sepsis is characterized by life-threatening organ dysfunction caused by a dysregulated host response to infection and affects over 1 million Americans annually. Loss of glycemic control in sepsis is associated with increased morbidity and mortality, and novel approaches are needed to promote euglycemia and improve outcomes in sepsis. Recent studies from our laboratory demonstrate that early low-level enteral dextrose infusion in septic mice attenuates the systemic inflammatory response and improves glycemic control by inducing intestine-derived incretin hormone secretion.

AIM

The aim of the Study of Early Enteral Dextrose in Sepsis (SEEDS) is to test the effect of a 24-hour enteral dextrose infusion in critically ill septic patients as a therapeutic agent to decrease systemic inflammation and promote euglycemia.

METHODS

SEEDS is a single-center, double-blind, randomized, controlled trial that will enroll 60 septic patients admitted to the intensive care units at the University of Pittsburgh Medical Center Health System in Pittsburgh. Participants will be randomized 1:1 to receive enteral dextrose (n = 30) or water (placebo, n = 30) infusion for 24 hours. The primary outcome is the circulating interleukin-6 level measured after the 24-hour infusion compared between dextrose and placebo groups. Secondary outcomes include postinfusion circulating insulin, incretin, and other proinflammatory cytokine levels, as well as incidence of hyperglycemia and hypoglycemia during the infusion period.

DISCUSSION

This trial will characterize the effects of early enteral dextrose on endogenous endocrine pathways and the systemic inflammatory response in sepsis. The results of this trial will inform future larger interventional studies of early enteral nutrients in critically ill patients with sepsis.

Inhibition of GIP signaling extends lifespan without caloric restriction

AIMS/INTRODUCTION

Caloric restriction (CR) promotes longevity and exerts anti-aging effects by increasing Sirtuin production and activation. Gastric inhibitory polypeptide (GIP), a gastrointestinal peptide hormone, exerts various effects on pancreatic β-cells and extra-pancreatic tissues. GIP promotes glucose-dependent augmentation of insulin secretion and uptake of nutrients into the adipose tissue.

MATERIALS AND METHODS

Gipr^-/- and Gipr^+/+ mice were used for lifespan analysis, behavior experiments and gene expression of adipose tissue and muscles. 3T3-L1 differentiated adipocytes were used for Sirt1 and Nampt expression followed by treatment with GIP and α-lipoic acid.

RESULTS

We observed that GIP receptor-knockout (Gipr^-/-) mice fed normal diet showed an extended lifespan, increased exploratory and decreased anxiety-based behaviors, which are characteristic behavioral changes under CR. Moreover, Gipr^-/- mice showed increased Sirt1 and Nampt expression in the adipose tissue. GIP suppressed α-lipoic acid-induced Sirt1 expression and activity in differentiated adipocytes.

CONCLUSIONS

Although maintenance of CR is difficult, food intake and muscle endurance of Gipr^-/- mice were similar to those of wild-type mice. Inhibition of GIP signaling may be a novel strategy to extend the lifespan of diabetic patients.

The GLP-1 receptor agonist liraglutide protects against oxidized LDL-induced endothelial inflammation and dysfunction via KLF2

Cardiovascular complications are the major causes of the mortality and morbidities in diabetic patients. The diabetic patients have an increased risk of developing atherosclerosis, which could lead to heart attack and stroke. Glucagon-like peptide 1 (GLP-1) receptor agonists are a class of potent anti-glycemic agents to treat diabetes. Recently, several GLP-1 receptor agonists have been found to have cardiovascular benefit independent of their glucose lowing ability. Liraglutide is one of clinically approved effective GLP-1 receptor agonists. In this study, we explored the molecular mechanism of Liraglutide against oxidized low-density lipoprotein (ox-LDL) in cultured endothelial cells. Our data show that Liraglutide treatment ameliorates ox-LDL caused reduction of the transcriptional factor KLF2. In the same experiment, Liraglutide also rescues ox-LDL induced reduction of mitogen-activated protein kinase (MAPK) kinase extracellular signal regulated kinase 5 (ERK5) phosphorylation, and blockage of ERK5 activity by its inhibitor XMD8-92 abolishes the protection of Liraglutide on KLF2 expression. These facts suggest that the action of Liraglutide on endothelial KLF2 is dependent on ERK5. Liraglutide also recovers ox-LDL caused reduction of endothelial tight junctions protein Occludin and ameliorates ox-LDL induced endothelial monolayer permeability increase. On the other hand, Liraglutide inhibits ox-LDL induced expression of vascular adhesion molecules (E-selectin and vascular cell adhesion molecule 1), and prevents ox-LDL induced attachment of monocytes adhesion to endothelial cells. Moreover, Liraglutide mitigates ox-LDL triggered reduction of endothelial nitric oxide synthase (eNOS) expression and NO release. Collectively, our study provides multiple facets of the mechanisms that Liraglutide is a protective agent in endothelial cells and has the potential implication in therapeutic usage of vascular complication in diabetes patients. © 2019 IUBMB Life, 71(9):1347-1354, 2019.

Pharmacokinetics and efficacy of PT302, a sustained-release Exenatide formulation, in a murine model of mild traumatic brain injury

Traumatic brain injury (TBI) is a neurodegenerative disorder for which no effective pharmacological treatment is available. Glucagon-like peptide 1 (GLP-1) analogues such as Exenatide have previously demonstrated neurotrophic and neuroprotective effects in cellular and animal models of TBI. However, chronic or repeated administration was needed for efficacy. In this study, the pharmacokinetics and efficacy of PT302, a clinically available sustained-release Exenatide formulation (SR-Exenatide) were evaluated in a concussive mild (m)TBI mouse model. A single subcutaneous (s.c.) injection of PT302 (0.6, 0.12, and 0.024 mg/kg) was administered and plasma Exenatide concentrations were time-dependently measured over 3 weeks. An initial rapid regulated release of Exenatide in plasma was followed by a secondary phase of sustained-release in a dose-dependent manner. Short- and longer-term (7 and 30 day) cognitive impairments (visual and spatial deficits) induced by weight drop mTBI were mitigated by a single post-injury treatment with Exenatide delivered by s.c. injection of PT302 in clinically translatable doses. Immunohistochemical evaluation of neuronal cell death and inflammatory markers, likewise, cross-validated the neurotrophic and neuroprotective effects of SR-Exenatide in this mouse mTBI model. Exenatide central nervous system concentrations were 1.5% to 2.0% of concomitant plasma levels under steady-state conditions. These data demonstrate a positive beneficial action of PT302 in mTBI. This convenient single, sustained-release dosing regimen also has application for other neurological disorders, such as Alzheimer's disease, Parkinson's disease, multiple system atrophy and multiple sclerosis where prior preclinical studies, likewise, have demonstrated positive Exenatide actions.

The effects of incretin-based therapies on β-cell function and insulin resistance in type 2 diabetes: A systematic review and network meta-analysis combining 360 trials

AIM

To evaluate the comparative effects of incretin-based therapies, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dipeptidyl peptidase-4 inhibitors (DPP-4Is), on β-cell function and insulin resistance in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Medline, Embase, the Cochrane Library and www.clinicaltrials.gov were searched for randomized controlled trials (RCTs) with a duration of at least 4 weeks. Network meta-analysis was performed, followed by subgroup analysis and meta-regression. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the quality of evidence. Outcomes of interest include homeostasis model assessment for β cell function (HOMA-β) and insulin resistance (HOMA-IR), fasting C-peptide and fasting plasma glucose (FPG). Weighted mean difference (WMD) with 95% confidence interval (CI) was calculated as the measure of effect size.

RESULTS

A total of 360 RCTs (74% at least double-blinded) with 157 696 patients were included. Incretin-based therapies were compared with six other classes of glucose-lowering drugs or with placebo. Compared with placebo, a significant increase in HOMA-β and fasting C-peptide was detected for GLP-1RAs (WMD = 20.31 [95% CI, 16.34-24.39] with low quality; WMD = 0.16 ng/mL [95% CI, 0.03-0.29] with low quality) and for DPP-4Is (WMD = 9.90 [95% CI, 8.27-11.61] with moderate quality; WMD = 0.09 ng/mL [95% CI, 0.04-0.14] with moderate quality) separately, while a significant reduction in HOMA-IR and FPG were found in favour of GLP-1RAs (WMD = -0.67 [95% CI, -1.08 to -0.27] with low quality; WMD = -1.04 mmol/L [95% CI, -1.26 to -0.83] with moderate quality) and DPP-4Is (WMD = -0.23 [95% CI, -0.38 to -0.08] with low quality; WMD = -0.77 mmol/L [95% CI, -0.98 to -0.57] with moderate quality), respectively.

CONCLUSIONS

Incretin-based therapies not only show an increase in HOMA-β and fasting C-peptide level, but also achieve a reduction in HOMA-IR and FPG in comparison with placebo. Although GRADE scores indicate low to moderate for most comparisons, incretin-based therapies seem to be an advisable option for long-term treatment to preserve β-cell function.

Topical, systemic and biologic therapies in hidradenitis suppurativa: pathogenic insights by examining therapeutic mechanisms

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the skin, manifesting in chronic, recurrent painful pustules, nodules, boils and purulent draining abscesses. Our current understanding of the pathogenesis of the disease is incomplete. This review aims to identify available treatment options in HS and discuss the pharmacological mechanisms through which such agents function. Identifying common pathways may inform our understanding of the pathogenesis of HS as well as identify future therapeutic targets. The pharmacological mechanisms implicated in topical therapies, antibiotic, hormonal, systemic immunomodulatory and biologic therapies for HS are discussed. Significant differences exist between agents and implicated pathways in therapy for mild and severe disease. This is an expression of the possible dichotomy in inflammatory pathways (and treatment responses) in HS. Studies involving monoclonal antibodies provide the greatest insight into what these specific mechanisms may be. Their variable levels of clinical efficacy compared with placebo bolsters the suggestion that differential inflammatory pathways may be involved in different presentations and severity of disease. Nuclear factor kappa B (NF-κB), tumor necrosis factor (TNF)-α and other innate immune mechanisms are strongly represented in treatments which are effective in mild to moderate disease in the absence of scarring or draining fistulae, however complex feed-forward mechanisms in severe disease respond to interleukin (IL)-1 inhibition but are less likely to respond to innate immune inhibition (through NF-κB or TNF-α) alone. It is unclear whether IL-17 inhibition will parallel TNF-α or IL-1 inhibition in effect, however it is plausible that small molecule targets (Janus kinase1 and phosphodiesterase 4) may provide effective new strategies for treatment of HS.

Cardiovascular safety of oral semaglutide in patients with type 2 diabetes: Rationale, design and patient baseline characteristics for the PIONEER 6 trial

AIMS

To assess the cardiovascular (CV) safety of oral semaglutide, the first tablet formulation of a glucagon-like peptide-1 receptor agonist.

MATERIALS AND METHODS

PIONEER 6 is a multinational, randomized, placebo-controlled, double-blind trial in patients with type 2 diabetes at high risk of CV events (defined as being aged ≥50 years and having established CV disease [CVD] or moderate [stage 3] chronic kidney disease [CKD], or being aged ≥60 years with ≥1 other CV risk factor). Patients were randomized to once-daily oral semaglutide (up to 14 mg) or placebo added to standard of care. The primary composite endpoint is time to first occurrence of CV death or non-fatal myocardial infarction or non-fatal stroke. The primary hypothesis was to exclude an excess in CV risk with oral semaglutide by assessing non-inferiority versus placebo for the primary endpoint (non-inferiority margin of 1.8 for the upper boundary of the 95% confidence interval of the hazard ratio). PIONEER 6 is event-driven, with follow-up continuing until accrual of at least 122 primary outcome events. There is no pre-defined minimal duration.

RESULTS

Overall, 3183 patients have been enrolled (mean age 66.1 years, 31.6% females) in 214 sites across 21 countries. At baseline, the mean duration of diabetes was 14.9 years, mean glycated haemoglobin concentration was 66 mmol/mol (8.2%), and 84.6% of patients had established CVD/moderate CKD.

CONCLUSIONS

PIONEER 6 will provide evidence regarding the CV safety of oral semaglutide in patients with type 2 diabetes and high CV risk.

Exenatide corrects postprandial hyperglycaemia in young people with cystic fibrosis and impaired glucose tolerance: A randomized crossover trial

Impaired glucose tolerance (IGT) in cystic fibrosis (CF) manifests as postprandial hyperglycaemia. Pancreatic enzyme supplementation reduces the latter; restoring incretin secretion and slowing gastric emptying. We aimed to determine the acute effect of exenatide on postprandial glycaemia in young people with CF and IGT. Six participants with CF and IGT were studied on 2 days, in a double-blind randomized crossover trial. After overnight fasting, they received exenatide 2.5 mcg or placebo (0.9% saline) subcutaneously 15 minutes before a pancake meal labelled with ¹³ C octanoate and pancreatic enzyme replacement. The primary outcomes, area under the curve over 240 minutes (AUC ₂₄₀ ) for blood glucose (P < 0.0001) and peak blood glucose (7.65 mM ± 0.34 [mean ± SE] vs 9.53 mM ± 0.63, P < 0.0001), were markedly lower after exenatide than placebo. AUC₂₄₀ for insulin, C-peptide, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) was also lower after exenatide. Gastric emptying was markedly slower after exenatide, as assessed by time for 10% gastric emptying and peak ¹³ CO₂ excretion. We report for the first time that exenatide corrects postprandial hyperglycaemia in young people with CF and IGT. GLP-1 agonists are a candidate treatment in CF-related diabetes.

Neuroprotective Actions of Glucagon-Like Peptide-1 (GLP-1) Analogues in Alzheimer's and Parkinson's Diseases

The current absence of effective treatments for Alzheimer's disease (AD) and Parkinson's disease (PD) reflects an incomplete knowledge of the underlying disease processes. Considerable efforts have been made to investigate the central pathological features of these diseases, giving rise to numerous attempts to develop compounds that interfere with such features. However, further characterization of the molecular targets within the interconnected AD and PD pathways is still required. Impaired brain insulin signaling has emerged as a feature that contributes to neuronal dysfunction in both AD and PD, leading to strategies aiming at restoring this pathway in the brain. Long-acting glucagon-like peptide-1 (GLP-1) analogues marketed for treatment of type 2 diabetes mellitus have been tested and have shown encouraging protective actions in experimental models of AD and PD as well as in initial clinical trials. We review studies revealing the neuroprotective actions of GLP-1 analogues in pre-clinical models of AD and PD and promising results from recent clinical trials.

Stage-Based Management of Type 2 Diabetes Mellitus with Heart Failure

Type 2 diabetes negatively impacts heart failure outcomes. Insulin resistance, central adiposity, dyslipidemia, and altered cellular substrate metabolism each have a mechanistic role. Management strategies focused solely on glycemic control have had limited success. However, three new classes of drugs, each with several options, offer the promise of improved diabetes management in heart failure. Unlike earlier classes, these medications have had favorable cardiovascular outcomes. In this review, we present a therapeutic guide for metabolic treatment based on the stages of heart failure.

Seafood intake and the development of obesity, insulin resistance and type 2 diabetes

We provide an overview of studies on seafood intake in relation to obesity, insulin resistance and type 2 diabetes. Overweight and obesity development is for most individuals the result of years of positive energy balance. Evidence from intervention trials and animal studies suggests that frequent intake of lean seafood, as compared with intake of terrestrial meats, reduces energy intake by 4–9 %, sufficient to prevent a positive energy balance and obesity. At equal energy intake, lean seafood reduces fasting and postprandial risk markers of insulin resistance, and improves insulin sensitivity in insulin-resistant adults. Energy restriction combined with intake of lean and fatty seafood seems to increase weight loss. Marine n-3 PUFA are probably of importance through n-3 PUFA-derived lipid mediators such as endocannabinoids and oxylipins, but other constituents of seafood such as the fish protein per se, trace elements or vitamins also seem to play a largely neglected role. A high intake of fatty seafood increases circulating levels of the insulin-sensitising hormone adiponectin. As compared with a high meat intake, high intake of seafood has been reported to reduce plasma levels of the hepatic acute-phase protein C-reactive protein level in some, but not all studies. More studies are needed to confirm the dietary effects on energy intake, obesity and insulin resistance. Future studies should be designed to elucidate the potential contribution of trace elements, vitamins and undesirables present in seafood, and we argue that stratification into responders and non-responders in randomised controlled trials may improve the understanding of health effects from intake of seafood.

Glucagon Levels During Short-Term SGLT2 Inhibition Are Largely Regulated by Glucose Changes in Patients With Type 2 Diabetes

CONTEXT

The mechanism mediating sodium glucose cotransporter-2 (SGLT2) inhibitor-associated increase in glucagon levels is unknown.

OBJECTIVE

To assess short-term effects on glucagon, other hormones, and energy substrates after SGLT2 inhibition and whether such effects are secondary to glucose lowering. The impact of adding a dipeptidyl peptidase-4 inhibitor was addressed.

DESIGN, SETTING, AND PATIENTS

A phase 4, single-center, randomized, three-treatment crossover, open-label study including 15 patients with type 2 diabetes treated with metformin.

INTERVENTIONS

Patients received a single-dose of dapagliflozin 10 mg accompanied by the following in randomized order: isoglycemic clamp (experiment DG); saline infusion (experiment D); or saxagliptin 5 mg plus saline infusion (experiment DS). Directly after 5-hour infusions, a 2-hour oral glucose tolerance test (OGTT) was performed.

RESULTS

Glucose and insulin levels were stable in experiment DG and decreased in experiment D [P for difference (Pdiff) < 0.001]. Glucagon-to-insulin ratio (Pdiff < 0.001), and levels of glucagon (Pdiff < 0.01), nonesterified fatty acids (Pdiff < 0.01), glycerol (Pdiff < 0.01), and β-OH-butyrate (Pdiff < 0.05) were lower in DG vs D. In multivariate analysis, change in glucose level was the main predictor of change in glucagon level. In DS, glucagon and active GLP-1 levels were higher than in D, but glucose and insulin levels did not differ. During OGTT, glucose levels rose less and glucagon levels fell more in DS vs D.

CONCLUSION

The degree of glucose lowering markedly contributed to regulation of glucagon and insulin secretion and to lipid mobilization during short-term SGLT2 inhibition.

GLP-1 Receptor in Pancreatic α-Cells Regulates Glucagon Secretion in a Glucose-Dependent Bidirectional Manner

Glucagon-like peptide 1 (GLP-1) is known to suppress glucagon secretion, but the mechanism by which GLP-1 exerts this effect is unclear. In this study, we demonstrated GLP-1 receptor (GLP-1R) expression in α-cells using both antibody-dependent and antibody-independent strategies. A novel α-cell-specific GLP-1R knockout (αGLP-1R^-/-) mouse model was created and used to investigate its effects on glucagon secretion and glucose metabolism. Male and female αGLP-1R^-/- mice both showed higher nonfasting glucagon levels than their wild-type littermates, whereas insulin and GLP-1 levels remained similar. Female αGLP-1R^-/- mice exhibited mild glucose intolerance after an intraperitoneal glucose administration and showed increased glucagon secretion in response to a glucose injection compared with the wild-type animals. Furthermore, using isolated islets, we confirmed that αGLP-1R deletion did not interfere with β-cell function but affected glucagon secretion in a glucose-dependent bidirectional manner: the αGLP-1R^-/- islets failed to inhibit glucagon secretion at high glucose and failed to stimulate glucagon secretion at very low glucose condition. More interestingly, the same phenomenon was recapitulated in vivo under hypoglycemic and postprandial (fed) conditions. Taken together, this study demonstrates that GLP-1 (via GLP-1R in α-cells) plays a bidirectional role, either stimulatory or inhibitory, in glucagon secretion depending on glucose levels.

Effects of liraglutide addition to multiple diabetes regimens on weight and risk of hypoglycemia for a cohort with type 2 diabetes followed in primary care clinics in Saudi Arabia

Context:

Available therapies for type 2 diabetes mellitus (T2DM) do not adequately control glycemia in the long term as they do not address the issue of declining beta cell function and do not impact positively on weight or cardiovascular concerns associated with the disease.

Aims:

To measure changes in hemoglobin A1c, weight, and hypoglycemia after the addition of liraglutide to 3 therapeutic regimens of patients with T2DM.

Settings and Design:

An observational cohort study that was implemented in Al-Wazarat Health Center in Riyadh, Saudi Arabia.

Methods and Materials:

The study included 38 T2DM patients who were screened for initiation of liraglutide in combination with their treatment regimens; sulphonylurea, sulphonylurea with basal insulin (glargine), and multiple daily injections of insulin. The cohort was followed for 12 months, and the liraglutide was started with 0.6 mg dose that escalated to 1.2 and 1.8 mg. Glycemic level and weight were measured 3 times, whereas hypoglycemia was measured 2 times.

Statistical Analysis Used:

Quantitative continuous paired data were compared using a paired t-test and the nonparametric Wilcoxon signed rank test.

Results:

There was a statistically significant reduction of hemoglobin A1c with 1.2 mg dose (mean difference = 0.84%, P = 0.003). There were no statistically significant differences regarding the effect of liraglutide in addition to the 3 treatment regimens on patients’ weight (P = 0.08, 0.472, 0.08, respectively). Regarding hypoglycemia, liraglutide has showed minimal effect.

Conclusions:

Sustained effect of liraglutide on glycemic control in patients with T2DM without any major hypoglycemic episodes.

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.

Real-world GLP-1 RA therapy in type 2 diabetes: A long-term effectiveness observational study

AIMS

To evaluate in a real-world setting the effectiveness and tolerability of available GLP-1 RA drugs in patients with type 2 diabetes after a prolonged follow-up.

MATERIALS AND METHODS

Observational, retrospective, single-centre study in patients starting GLP-1 RA therapy. Change in HbA1c, fasting plasma glucose (FPG) and body mass index (BMI) along with gastrointestinal (GI) adverse events and withdrawal from GLP-1 RA therapy were evaluated. Lack of efficacy of GLP-1 RA therapy according to prespecified goals was also measured.

RESULTS

A total of 735 patients were included, mean age 59.7 years, duration of diabetes 9.01 years, HbA1c 8.18% and BMI 38.56 kg/m2. Average follow-up was 18.97 months (range 4.2-39.09). All HbA1c (0.93%; P < 0.01), FPG (24 mg/dL; P < 0.01) and BMI (1.55 kg/m2; P < 0.05) were significantly reduced from baseline and maintained throughout follow-up, regardless of prescribed GLP-1 RA. GI adverse events were present in 13.81% of patients at first follow-up visit, 37.07% of patients discontinued GLP-1 RA treatment, and 38.63% did not meet efficacy goals.

CONCLUSIONS

In a real-world setting, GLP-1 RA therapy is largely prescribed in severely obese patients with a long-standing and poorly controlled diabetes. All prescribed GLP-1 RAs significantly decreased HbA1c, FPG and BMI. GI adverse events affected a low proportion of patients. Inversely, a high proportion of patients did not meet efficacy goals and/or discontinued GLP-1 RA treatment. Baseline characteristics of patients and lack of adherence may represent important issues underlying differences in effectiveness in real-world studies versus randomized trials.

Efficacy of liraglutide in treating type 2 diabetes mellitus complicated with non-alcoholic fatty liver disease

Type 2 diabetes mellitus (T2DM) complicated with non-alcoholic fatty liver disease (NAFLD) is difficult to treat. The present study explored the efficacy of (liraglutide) Lira in treating T2DM complicated with NAFLD. A total of 127 patients suffering from T2DM complicated with NAFLD were enrolled in the present study, and randomly assigned to a Lira group (liraglutide injection: 0.6–1.2 mg/day, 12 weeks, n=52) or a Metformin (Met) group (oral metformin: 1000–1500 mg/day, 12 weeks, n=75). During the treatment phase, the values for fasting plasma glucose (FPG), 2 h plasma glucose (2hPG), glycated hemoglobin (HbA1c), aspartate aminotransferase (AST)/alanine aminotransferase (ALT), and adiponectin (APN) decreased in both the Lira and Met groups, and the levels of Δ2hPG, ΔAST/ALT, and ΔAPN in the Lira group were significantly lower than those in the Met group. The values for total cholesterol (TC), triglycerides (TG), low-and high-density lipoproteins (LDL and HDL), ALT, AST, weight, body mass index (BMI), waist to hip ratio (WHR), and C-reactive protein were markedly increased in both groups, and levels of ΔAST, ΔALT, Δweight, ΔBMI, ΔWHR, and ΔCRP (C-reactive protein) in the Lira group were significantly higher than those in the Met group. An analysis of treatment efficacy showed that liraglutide was better than metformin in its ability to significantly decrease the ALT levels in patients with combined T2DM and NAFLD. Furthermore, liraglutide was more effective than metformin at ameliorating the severity of T2DM complicated with NAFLD, and produced its effects by alleviating liver inflammation and improving liver function.

Macrocarpal C isolated from Eucalyptus globulus inhibits dipeptidyl peptidase 4 in an aggregated form

Dipeptidyl peptidase 4 (DPP-4) inhibitors are used for the treatment of type-2 diabetes mellitus. Various synthetic inhibitors have been developed to date, and plants containing natural DPP-4 inhibitors have also been identified. Here, 13 plant samples were tested for their DPP-4 inhibitory activity. Macrocarpals A-C were isolated from Eucalyptus globulus through activity-guided fractionation and shown to be DPP-4 inhibitors. Of these, macrocarpal C showed the highest inhibitory activity, demonstrating an inhibition curve characterised by a pronounced increase in activity within a narrow concentration range. Evaluation of macrocarpal C solution by turbidity, nuclear magnetic resonance spectroscopy and mass spectrometry indicated its aggregation, which may explain the characteristics of the inhibition curve. These findings will be valuable for further study of potential small molecule DPP-4 inhibitors.

Pharmacokinetics, Safety and Tolerability of Oral Semaglutide in Subjects with Renal Impairment

BACKGROUND

Semaglutide, a glucagon-like peptide-1 (GLP-1) analogue, has been co-formulated with the absorption enhancer sodium N-(8-[2-hydroxybenzoyl] amino) caprylate (SNAC) as a tablet for oral administration. This trial (NCT02014259) investigated the pharmacokinetics, safety and tolerability of oral semaglutide in subjects with and without renal impairment.

METHODS

Subjects were categorised as having normal renal function (n = 24), mild (n = 12), moderate (n = 12) or severe (n = 12) renal impairment, or end-stage renal disease (ESRD) requiring haemodialysis (n = 11) and received once-daily oral semaglutide (5 mg for 5 days followed by 10 mg for 5 days) in the fasting state, followed by 30 min fasting after dosing. Semaglutide plasma concentrations were measured during dosing and for up to 21 days after the last dose.

RESULTS

Semaglutide exposure (area under the plasma concentration-time curve from time zero to 24 h after the tenth dose and maximum concentration after the tenth dose) did not vary in a consistent pattern across the renal function groups. Similarly, there was no apparent effect of renal impairment on the semaglutide half-life (geometric mean range 152-165 h). Except for one subject in the ESRD group, semaglutide was not detected in urine. Haemodialysis did not affect the pharmacokinetics of semaglutide. Adverse events were in line with those observed for other GLP-1 receptor agonists and no safety concerns were identified.

CONCLUSION

There was no apparent effect of renal impairment or haemodialysis on the pharmacokinetics of oral semaglutide. Based on this trial, renal impairment should not affect dose recommendations for oral semaglutide.

Silver Nanoparticle Conjugation-Enhanced Antibacterial Efficacy of Clinically Approved Drugs Cephradine and Vildagliptin

This paper sets out to determine whether silver nanoparticles conjugation enhance the antibacterial efficacy of clinically approved drugs. Silver conjugated Cephradine and Vildagliptin were synthesized and thoroughly characterized by ultraviolet visible spectrophotometry (UV-vis), Fourier transform infrared (FT-IR) spectroscopic methods, atomic force microscopy (AFM), and dynamic light scattering (DLS) analysis. Using antibacterial assays, the effects of drugs alone and drugs-conjugated with silver nanoparticles were tested against a variety of Gram-negative and Gram-positive bacteria including neuropathogenic Escherichia coli K1, Pseudomonas aeruginosa, Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA), Bacillus cereus and Streptococcus pyogenes. Cytopathogenicity assays were performed to determine whether pretreatment of bacteria with drugs inhibit bacterial-mediated host cell cytotoxicity. The UV-vis spectra of both silver-drug nanoconjugates showed a characteristic surface plasmon resonance band in the range of 400–450 nm. AFM further confirmed the morphology of nanoparticles and revealed the formation of spherical nanoparticles with size distribution of 30–80 nm. FT-IR analysis demonstrated the involvement of Hydroxyl groups in both drugs in the stabilization of silver nanoparticles. Antibacterial assays showed that silver nanoparticle conjugation enhanced antibacterial potential of both Cephradine and Vildagliptin compared to the drugs alone. Pretreatment of bacteria with drugs inhibited E. coli K1-mediated host cell cytotoxicity. In summary, conjugation with silver nanoparticle enhanced antibacterial effects of clinically approved Cephradine. These findings suggest that modifying and/or repurposing clinically approved drugs using nanotechnology is a feasible approach in our search for effective antibacterial molecules.

Oral formulation of DPP-4 inhibitor plus Quercetin improves metabolic homeostasis in type 1 diabetic rats

This study aimed to investigate the potential of an oral formulation (QV formulation) containing Quercetin and a Dipeptidyl Peptidase-4 Inhibitor (DPP-4 inhibitor), Vildagliptin, in improving metabolic homeostasis in type 1 diabetes model. Female albino Fischer rats were divided into four groups: untreated control animals (C), untreated diabetic animals (D), diabetic animals treated with QV formulation (DQV), and diabetic animals treated with insulin (DI). Diabetes was induced by injection of alloxan (135 mg kg body mass)^-1 and confirmed by glycemic test. After the 30-day treatment period, biochemical parameters were analyzed in the pancreas, liver, and serum. Histopathological changes in pancreatic tissue were examined by Hematoxyline & Eosin staining and the insulin content in the islet measured by immunohistochemistry with anti-insulin antibody. The glycogen content in the hepatocytes was quantified by Periodic Schiff Acid staining. The QV formulation reduced the glycemia, preserved the pancreatic architecture, increased insulin levels, furthermore ameliorated lipid profile and to promote higher survival rate of animals. Together, our data suggest that the QV formulation treatment was able to normalize metabolic homeostasis in type 1 diabetic rats.

Roles of Gut-Derived Secretory Factors in the Pathogenesis of Non-Alcoholic Fatty Liver Disease and Their Possible Clinical Applications

The rising prevalence of non-alcoholic fatty liver disease (NAFLD) parallels the global increase in the number of people diagnosed with obesity and metabolic syndrome. The gut-liver axis (GLA) plays an important role in the pathogenesis of NAFLD/non-alcoholic steatohepatitis (NASH). In this review, we discuss the clinical significance and underlying mechanisms of action of gut-derived secretory factors in NAFLD/NASH, focusing on recent human studies. Several studies have identified potential causal associations between gut-derived secretory factors and NAFLD/NASH, as well as the underlying mechanisms. The effects of gut-derived hormone-associated drugs, such as glucagon-like peptide-1 analog and recombinant variant of fibroblast growth factor 19, and other new treatment strategies for NAFLD/NASH have also been reported. A growing body of evidence highlights the role of GLA in the pathogenesis of NAFLD/NASH. Larger and longitudinal studies as well as translational research are expected to provide additional insights into the role of gut-derived secretory factors in the pathogenesis of NAFLD/NASH, possibly providing novel markers and therapeutic targets in patients with NAFLD/NASH.

Anti-Diabetic Medications for the Pharmacologic Management of NAFLD

As a chronic disease encompassing a wide spectrum of liver-related histologic damage, nonalcoholic fatty liver disease (NAFLD) is becoming a global epidemic with significant impacts on all-cause morbidity and mortality. Insulin resistance and type 2 diabetes mellitus predispose individuals to NAFLD and related complications. Therefore, timely intervention with anti-diabetic medications may prevent and delay the development of NAFLD or have a therapeutic implication. The focus of this review is to evaluate the evidence supporting the efficacy of anti-diabetic medications in the treatment of NAFLD. While many of these anti-diabetic agents have shown to improve biochemical parameters, their effect on hepatic histology is limited. Among anti-diabetic medications, only thiazolidinediones and glucagon-like peptide-1 receptor agonists demonstrate significant improvement in hepatic histology.

Up-Titration Strategy After DPP-4 Inhibitor-Based Oral Therapy for Type 2 Diabetes: A Randomized Controlled Trial Shifting to a Single-Dose GLP-1 Enhancer Versus Adding a Variable Basal Insulin Algorithm

INTRODUCTION

It is unclear whether adding basal insulin or enhancing incretin signaling with a glucagon-like peptide-1 receptor agonist (GLP-1RA) is more effective as an up-titration strategy after dipeptidyl peptidase-4 inhibitor (DPP-4i)-based oral antidiabetic drug (OAD) therapy. GLP-1RAs can be injected without dose adjustment, unlike basal insulin. Our objective was to examine the efficacy of changing patients inadequately controlled with oral DPP-4i-based OAD therapy to injectable GLP-1RA and discontinuing the DPP4i versus adding basal insulin glargine (IGlar) with the continuation of the oral DPP4i.

METHODS

Sixty patients with type 2 diabetes (T2DM) and glycated hemoglobin (HbA1c) between 7.0% and 10.0% on DPP-4i-based OAD therapy were randomized to either adding IGlar and remaining on the DPP-4i or liraglutide and discontinuing the DPP-4i for 24 weeks. Patients in the IGlar group started with 0.1 unit/kg and were titrated according to the algorithm. In the liraglutide group, the DPP-4i was replaced with liraglutide 0.9 mg/day, the maximum dose in Japan. We evaluated HbA1c, glycated albumin (GA), and anthropometrics.

RESULTS

HbA1c was significantly lower at week 24 (- 1.0 ± 0.9% in the IGlar group and - 0.6 ± 0.8% in the liraglutide group), but the difference between groups was not significant. Changes in GA were similar (- 2.9 ± 3.2% vs. - 2.6 ± 3.2%) in both groups. Body weight (BW) was significantly lower only in the liraglutide group (+ 0.5 ± 2.6 kg vs. - 2.2 ± 2.0 kg). The rate of minor hypoglycemic episodes was similar for both groups.

CONCLUSION

For poorly controlled T2DM on DPP-4i-based OAD therapy, switching to single-dose liraglutide to enhance incretin signaling is as effective as dose-titrated basal IGlar, but significant BW reduction was only seen in the liraglutide group. These results suggest that enhancing incretin signaling with a single-dose injectable GLP-1 RA might be an alternative to dose-titrated basal insulin therapy in patients with T2DM poorly controlled with DPP-4i-based OAD therapy. These findings should be confirmed in a longer and larger trial.

TRIAL REGISTRATION

Trial Registry (UMIN-CTR) as UMIN000012224.

Comprehensive Evaluation of Combination Therapy with Basal Insulin and Either Lixisenatide or Vildagliptin in Japanese Patients with Type 2 Diabetes: A Randomized, Open-Label, Parallel-Group, Multicenter Study

INTRODUCTION

We comprehensively evaluated the effects of combination therapy with insulin glargine and the incretin-based drugs lixisenatide or vildagliptin in Japanese patients with type 2 diabetes.

METHODS

In this 12-week, randomized, open-label, parallel-group, multicenter study (GLP-ONE Kobe), the incretin-based drug sitagliptin was randomly switched to lixisenatide (20 μg/day, n = 18) or vildagliptin (100 mg/day, n = 20) in patients with inadequate glycemic control despite combination therapy with insulin glargine and sitagliptin. The dose of insulin glargine was titrated after the switch to maintain fasting blood glucose at approximately 110 mg/dL. The primary end points of the study were the change in glycosylated hemoglobin (HbA_1c) level between before and 12 weeks after the treatment switch, the proportion of patients achieving an HbA_1c level below 7.0%, and the postprandial increase in glucose concentration as assessed by self-monitoring of blood glucose.

RESULTS

The change in HbA_1c level from baseline to 12 weeks did not differ significantly between the lixisenatide and vildagliptin groups (- 0.6 ± 0.7% and - 0.6 ± 1.2%, respectively, P = 0.920). Neither the proportion of patients achieving an HbA_1c level below 7.0% nor the postprandial increase in glucose concentration was different between two groups. Body weight and serum low density lipoprotein (LDL) cholesterol level decreased significantly in the lixisenatide and vildagliptin groups, respectively. Both drugs were associated with mild gastrointestinal symptoms but not with severe hypoglycemia. Vildagliptin was associated with elevation of serum aspartate transaminase. Treatment satisfaction as assessed with the Diabetes Treatment Satisfaction Questionnaire did not differ significantly between the two groups.

CONCLUSION

The combinations of basal insulin and either lixisenatide or vildagliptin have similar efficacies with regard to improvement of glycemic control.

TRIAL REGISTRATION

This trial has been registered with UMIN (No. 000010769).

Comparing once-weekly semaglutide to incretin-based therapies in patients with type 2 diabetes: a systematic review and meta-analysis

AIMS

Our aim was to compare once-weekly semaglutide to incretin-based therapies - defined as either dipeptidyl peptidase-4 inhibitors (DPP-4i) or other glucagon-like peptide-1 receptor agonist (GLP-1RA) - in patients with type 2 diabetes.

METHODS

We searched for randomized trials comparing once-weekly semaglutide to other incretin-based therapies in patients with type 2 diabetes. We pooled trials that compared semaglutide to other GLP-1RA together, and those comparing semaglutide to DPP-4i together. The primary outcome was the change in haemoglobin A_1c over time.

RESULTS

Five trials met our inclusion criteria. There was a significantly greater reduction in haemoglobin A_1c favouring semaglutide when compared to other GLP-1RA or DPP-4i [MD (95% CI) = -0.38% (-0.62, -0.15) and -1.14% (-1.53, -0.75) respectively]. There was a significantly greater weight loss favouring semaglutide when compared to other GLP-1RA or DPP-4i [MD (95% CI) = -2.50 kg (-3.91, -1.09) and -3.19 kg (-3.66, -2.72) respectively]. The proportion of patients achieving glycaemic goals and goal weight loss was greater in semaglutide-treated patients when compared to either other GLP-1RA or DPP-4i. However, semaglutide-treated patients had a significantly higher incidence of gastrointestinal side effects.

CONCLUSIONS

While both once-weekly semaglutide and other incretin-based therapies can reduce haemoglobin A_1c, semaglutide causes a more potent haemoglobin A_1c reduction and greater weight loss when compared to other incretin-based therapies. However, this potent effect of semaglutide was associated with a higher incidence of gastrointestinal side effects. Additional studies are needed to determine whether this marked reduction in both haemoglobin A_1c and body weight may translate into improved cardiovascular outcomes.

Effect of liraglutide on physical performance in type 2 diabetes: Results of a randomized, double-blind, controlled trial (LIPER2)

AIMS

To assess the effect of the GLP-1 analogue liraglutide on measures of cardiac function and physical performance in patients with type 2 diabetes (T2D).

METHODS

In this phase-IV randomized double-blind placebo-controlled parallel-group clinical trial at a tertiary hospital, T2D patients with HbA_1c levels of 7-10% with oral agents and/or intermediate-/long-acting insulin were allocated (computer-generated randomization, ratio 1:1) to either liraglutide 1.8 mg/day or a placebo for 6 months. The primary endpoint was maximum oxygen consumption (VO_2max) during cycle ergometry, while other procedures included a 6-min walk test, echocardiography, anthropometry and blood tests. Safety endpoints were also monitored, and an intention-to-treat analysis was performed.

RESULTS

A total of 24 patients (15 women) aged 52 (11.7) years, with diabetes duration of 8.7 (5.8) years, BMI 34.98 (6.2) kg/m² and HbA_1c 8.2% (0.68%), were randomized to liraglutide 1.8 mg daily or placebo. There were no differences in VO_2max [17.98 (4.8) vs. 15.90 (4.96) mL/kg/min; P > 0.10], VE/VCO₂ slope [30.18 (4.8) vs. 32 (4.49)], left ventricular ejection fraction or 6-min walk test [530.7 (86) vs. 503.9 (84) m] at 6 months. HbA_1c was lower (6.7% vs. 7.7%; P =  0.005), with a trend towards lower maximum systolic blood pressure during ergometry [171.7 (24.4) vs. 192.5 (25.6); P = 0.052] in the liraglutide group at the end of the study. There were no severe adverse events.

CONCLUSION

In this trial, liraglutide improved glycaemic control in T2D, but had no significant effects on either physical performance or myocardial function.

Cardiovascular outcomes in patients who experienced a myocardial infarction while treated with liraglutide versus placebo in the LEADER trial

OBJECTIVE

Animal studies demonstrated that glucagon-like peptide-1 receptor agonists reduce myocardial necrosis following regional ischaemia induction. This effect may improve cardiovascular outcomes after myocardial infarction. Risk of cardiovascular death or hospitalisation for heart failure after myocardial infarction was evaluated in patients with type 2 diabetes at high cardiovascular risk in the LEADER trial.

METHODS

Data from patients randomised to liraglutide or placebo, in addition to standard of care, in Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results (LEADER) (NCT01179048) were analysed post hoc. Cox regression, with myocardial infarction as a time-dependent covariate, was used to analyse time from randomisation to a composite of cardiovascular death or hospitalisation for heart failure.

RESULTS

Patients who experienced myocardial infarction had a sevenfold higher risk of the composite endpoint (with myocardial infarction: n = 148, 25.0%; without myocardial infarction: n = 716, 8.2%; hazard ratio: 7.0; 95% confidence interval: 5.8, 8.4). The risk of the composite endpoint after myocardial infarction was not significantly lower in the liraglutide group ( n = 63, 23.0%) compared with placebo ( n = 85, 26.7%; hazard ratio: 0.91; 95% confidence interval: 0.66, 1.26).

CONCLUSION

The data demonstrated that having myocardial infarction significantly increased the risk of subsequent cardiovascular death or hospitalisation for heart failure. However, we did not find evidence for a reduced risk in these cardiovascular outcomes following myocardial infarction in patients treated with liraglutide versus placebo.

Inhibition of SNAT5 Induces Incretin-Responsive State From Incretin-Unresponsive State in Pancreatic β-Cells: Study of β-Cell Spheroid Clusters as a Model

β-Cell-β-cell interactions are required for normal regulation of insulin secretion. We previously found that formation of spheroid clusters (called K20-SC) from MIN6-K20 clonal β-cells lacking incretin-induced insulin secretion (IIIS) under monolayer culture (called K20-MC) drastically induced incretin responsiveness. Here we investigated the mechanism by which an incretin-unresponsive state transforms to an incretin-responsive state using K20-SC as a model. Glutamate production by glucose through the malate-aspartate shuttle and cAMP signaling, both of which are critical for IIIS, were enhanced in K20-SC. SC formed from β-cells deficient for aspartate aminotransferase 1, a critical enzyme in the malate-aspartate shuttle, exhibited reduced IIIS. Expression of the sodium-coupled neutral amino acid transporter 5 (SNAT5), which is involved in glutamine transport, was downregulated in K20-SC and pancreatic islets of normal mice but was upregulated in K20-MC and islets of rodent models of obesity and diabetes, both of which exhibit impaired IIIS. Inhibition of SNAT5 significantly increased cellular glutamate content and improved IIIS in islets of these models and in K20-MC. These results suggest that suppression of SNAT5 activity, which results in increased glutamate production, and enhancement of cAMP signaling endows incretin-unresponsive β-cells with incretin responsiveness.

The European Medicines Agency's approval of new medicines for type 2 diabetes

Since 2005, more than 40 new medicines for the treatment of type 2 diabetes have been introduced on the market. These consist of 15 new active substances establishing three new classes of non-insulin products, and several new or modified insulin products and combinations. The approval of these products in Europe is regulated via the centralized procedure at the European Medicines Agency. Demonstration of benefit with regard to improved glucose control remains the principal outcome required from confirmatory studies to demonstrate efficacy. For the majority of these new medicines approved since 2005, cardiovascular outcome trials have now been completed, and have invariably supported the cardiovascular safety of these products. In some of these trials additional important benefits have been observed, for instance, a reduction in major adverse cardiovascular events and improvement of renal outcome. The existing regulatory framework and the continuous adaption of regulatory requirements to emerging developments will continue to guide the approval of new products in the future.

Semaglutide as a therapeutic option for elderly patients with type 2 diabetes: Pooled analysis of the SUSTAIN 1-5 trials

The efficacy and safety of semaglutide vs comparators in non-elderly (<65 years) and elderly (≥65 years) patients with type 2 diabetes (T2D) across the SUSTAIN 1-5 trials were evaluated. Patients were randomized to once-weekly subcutaneous semaglutide (0.5 or 1.0 mg) vs placebo, sitagliptin, exenatide or insulin. The primary objective was change in HbA1c and secondary objectives were changes in body weight and safety. Mean HbA1c decreased from baseline by 1.2%-1.5% and 1.5%-1.9% vs 0%-0.9% (non-elderly, n = 3045) and by 1.3%-1.5% and 1.2%-1.8% vs 0.2%-1.0% (elderly, n = 854) with semaglutide 0.5 and 1.0 mg vs comparators. Similar reductions from baseline in mean body weight with semaglutide occurred in both age groups. Similar proportions of patients experienced adverse events; premature treatment discontinuations were higher in elderly vs non-elderly patients. No increased risk of severe or blood glucose-confirmed hypoglycaemia was seen with semaglutide vs comparators between age groups. Semaglutide had a comparable efficacy and safety profile in non-elderly and elderly patients across the SUSTAIN 1-5 trials, making it an effective treatment option for elderly patients with T2D.

Gestational diabetes mellitus: Multi-disciplinary treatment approaches

Gestational diabetes mellitus (GDM) is the most common metabolic disease of pregnancy, associated with several perinatal complications. Adequate glycemic control has been proved to decrease risk of GDM-related complications. Several studies have shown the beneficial effect of exercise and medical nutrition treatment on glycemic and weight control in GDM-affected women. Moreover, pharmacological agents, such as insulin and specific oral anti-diabetic agents can be prescribed safely during pregnancy, decreasing maternal blood glucose and, thus, perinatal adverse outcomes. Multi-disciplinary treatment approaches that include both lifestyle modifications (medical nutritional therapy and daily physical exercise) and pharmacological treatment, in cases of failure of the former, constitute the most effective approach. Insulin is the gold standard pharmacological agent for GDM treatment. Metformin and glyburide are two oral anti-diabetic agents that could serve as alternative, although not equal in terms of effectiveness and safety, treatment for GDM. As studies on short-term safety of metformin are reassuring, in some countries it is considered as first-line treatment for GDM management. More studies are needed to investigate the long-term effects on offspring. As safety issues have been raised on the use of glyburide during pregnancy, it must be used only when benefits surpass possible risks.

Cardiovascular safety of GLP-1 receptor agonists for diabetes patients with high cardiovascular risk: A meta-analysis of cardiovascular outcomes trials

AIM

To show long-term cardiovascular safety of the GLP-1 receptor agonists for diabetes patients with cardiovascular risk.

METHODS

For cardiovascular outcomes, the association between treatment and outcomes was estimated using the odds ratio and 95% confidence interval. I² test was adopted to assess the magnitude of heterogeneity between studies, with values more than 25%, 50%, and 75% defined as low, moderate, or high heterogeneity.

RESULTS

We combined data from four cardiovascular outcomes trials and prospectively blinded endpoint adjudication. 4105 cardiovascular events including cardiovascular death, acute MI or stroke experienced during the trials. And the odds ratios of the cardiovascular outcomes were 0.90 (95% CI 0.81, 1.00) for the cardiovascular outcome, 0.93 (95% CI 0.85, 1.02) for nonfatal myocardial infarction, 0.88 (95% CI 0.76, 1.03) for nonfatal stroke, 0.94 (95% CI 0.84, 1.05) for heart failure hospitalization, 0.89 (95% CI 0.63, 1.27) for pancreatitis, 0.98 (95% CI 0.92, 1.05) for any hypoglycemic events, 0.92 (95% CI 0.83, 1.01) for the severe hypoglycemic events, 0.96 (95% CI 0.83, 1.01) for serious adverse events. Significant differences showed in mortality parameters: 0.88 (95% CI 0.81, 0.95) for all-cause mortality, 0.87 (95% CI 0.79, 0.97) for cardiovascular mortality. CV benefits were obtained in the male, black, Asian patients and patients with BMI ≥ 30 kg/m².

CONCLUSION

Additional GLP-1 receptor agonists treatment did not increase cardiovascular outcomes in diabetes patients with high cardiovascular risk or established cardiovascular disease.

DPP-IV Inhibitory Potentials of Flavonol Glycosides Isolated from the Seeds of Lens culinaris: In Vitro and Molecular Docking Analyses

Dipeptidyl peptidase IV (DPP-IV), a new target for the treatment of type 2 diabetes mellitus, degrades incretins such as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide. DPP-IV inhibitors shorten the inactivation of GLP-1, permitting the incretin to stimulate insulin release, thereby combating hyperglycemia. In our ongoing search for new DPP-IV inhibitors from medicinal plants and foods, three flavonol glycosides (1–3) were isolated from the seeds of Lens culinaris Medikus (Fabaceae) and tested for their DPP-IV–inhibitory activity. We demonstrated for the first time, that compounds 1–3 inhibited DPP-IV activity in a concentration-dependent manner in our in vitro bioassay system. In addition, molecular docking experiments of compounds 1–3 within the binding pocket of DPP-IV were conducted. All investigated compounds readily fit within the active sites of DPP-IV, in low-energy conformations characterized by the flavone core structure having optimal electrostatic attractive interactions with the catalytic triad residues of DPP-IV.

Switching from sitagliptin to liraglutide to manage patients with type 2 diabetes in the UK: A long-term cost-effectiveness analysis

AIMS

The recent LIRA-SWITCH trial showed that switching from sitagliptin 100 mg to liraglutide 1.8 mg led to statistically significant and clinically relevant improvements in glycated haemoglobin (HbA1C) and body mass index (BMI). Based on these findings, the aim of the present study was to assess the long-term cost-effectiveness of switching from sitagliptin to liraglutide in patients with type 2 diabetes in the UK.

MATERIALS AND METHODS

The IQVIA CORE Diabetes Model Version 8.5+ was used to project costs and clinical outcomes over patients' lifetimes. Baseline cohort characteristics and treatment effects were derived from the LIRA-SWITCH trial. Future costs and clinical benefits were discounted at 3.5% annually. Costs were accounted in pounds sterling (GBP) and expressed in 2016 values. One-way and probabilistic sensitivity analyses were performed.

RESULTS

Model projections showed improved quality-adjusted life expectancy for patients with poorly controlled HbA1c upon switching from sitagliptin to liraglutide, compared with continuing sitagliptin treatment (9.18 vs 9.02 quality-adjusted life years [QALYs]). Treatment switching was associated with increased overall costs (GBP 24737 vs GBP 22362). Higher pharmacy costs were partially offset by reduced diabetes-related complication costs in patients who switched to liraglutide. Switching to liraglutide was associated with an incremental cost-effectiveness ratio of GBP 15423 per QALY gained vs continuing with sitagliptin treatment.

CONCLUSIONS

Switching from sitagliptin 100 mg to liraglutide 1.8 mg in patients with poor glycaemic control was projected to improve clinical outcomes and is likely to be considered cost-effective in the UK setting and, therefore, a good use of limited NHS resources.

The effect of dulaglutide on body composition in type 2 diabetes mellitus patients on hemodialysis

AIMS

To evaluate the effect of dulaglutide on body composition in type 2 diabetes mellitus (T2DM) patients undergoing hemodialysis (HD).

METHODS

Twenty-one T2DM patients on HD, who had been treated with insulin and newly added teneligliptin (N = 10) or dulaglutide (N = 11), were enrolled. Body composition changes, such as fat mass (FM) and skeletal muscle mass (SMM), glycated albumin (GA), and insulin doses were compared before and after six months of treatment with teneligliptin or dulaglutide.

RESULTS

The percentage changes of GA and insulin doses were comparable between the teneliglipin and dulaglutide groups. Conversely, although FM and SMM did not change in the teneligliptin group (from 15.7 kg to 14.1 kg, P = 0.63 and 18.6 kg to 18.9 kg, P = 0.16, respectively), those in the dulaglutide group significantly decreased (from 21.9 kg to 18.9 kg, P = 0.037 and 21.0 kg to 20.2 kg, P = 0.011, respectively).

CONCLUSIONS

Six months of dulaglutide treatment significantly reduced not only FM but also SMM, although changes in GA and insulin doses were comparable with those in the teneligliptin group. Dulaglutide may have the effect of promoting sarcopenia; therefore, it may be carefully used in T2DM patients on HD.

Neoplasms Reported With Liraglutide or Placebo in People With Type 2 Diabetes: Results From the LEADER Randomized Trial

OBJECTIVE

This study explored neoplasm risk with liraglutide versus placebo in the LEADER (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results) cohort.

RESEARCH DESIGN AND METHODS

LEADER (NCT01179048) was an international, phase 3b, randomized, double-blind, controlled trial. Participants aged ≥50 years with type 2 diabetes and high cardiovascular risk were assigned 1:1 to receive liraglutide (≤1.8 mg daily; n = 4,668) or placebo (n = 4,672) in addition to standard care and monitored for 3.5-5 years (median follow-up 3.8 years). The occurrence of neoplasms was a prespecified, exploratory secondary end point. Post hoc analyses of the time to the first confirmed neoplasms were conducted using a Cox regression model.

RESULTS

Neoplasm was confirmed in 10.1% of patients with liraglutide versus 9.0% with placebo (hazard ratio [HR] 1.12 [95% CI 0.99; 1.28]). The HR (95% CI) for liraglutide versus placebo was 1.06 (0.90; 1.25) for malignant neoplasms and 1.16 (0.93; 1.44) for benign neoplasms. Sensitivity analyses excluding neoplasms occurring <1 year or <2 years after randomization and analyses by sex provided similar results. In our main analyses, the 95% CI for the HR included one for all malignant neoplasms evaluated (including pancreatic and thyroid neoplasms) except for prostate neoplasms, which occurred in fewer liraglutide-treated patients.

CONCLUSIONS

LEADER was not primarily designed to assess neoplasm risk. Firm conclusions cannot be made regarding numeric imbalances observed for individual neoplasm types (e.g., pancreatic cancer) that occurred infrequently. LEADER data do, however, exclude a major increase in the risk of total malignant neoplasms with liraglutide versus placebo. Additional studies are needed to assess longer-term exposure.

Safety and efficacy of the combination of the glucagon-like peptide-1 receptor agonist liraglutide with an oral antidiabetic drug in Japanese patients with type 2 diabetes: Post-hoc analysis of a randomized, 52-week, open-label, parallel-group trial

AIMS/INTRODUCTION

The aim of the present post-hoc analysis was to investigate the safety and efficacy of liraglutide in combination with one oral antidiabetic drug (OAD) across different OAD classes.

MATERIALS AND METHODS

This was a post-hoc analysis using data from a 52-week, open-label, parallel-group trial, in which patients with type 2 diabetes inadequately controlled with a single OAD (α-glucosidase inhibitor, glinide, metformin or thiazolidinedione) were randomized to either pretrial OAD in combination with liraglutide 0.9 mg/day (liraglutide group) or pretrial OAD in combination with an additional OAD (additional OAD group). The primary outcome investigated in this post-hoc analysis was the incidence of adverse events.

RESULTS

The proportions of patients experiencing adverse events across the different groups of pretrial OADs were comparable between liraglutide and additional OAD (α-glucosidase inhibitor 74.6 vs 70.0%; glinide 93.1 vs 87.1%; metformin 91.8 vs 87.1%; thiazolidinedione 86.2 vs 96.4%, respectively). Minor hypoglycemia was infrequent (seven episodes in two patients randomized to liraglutide, and two episodes in two patients randomized to additional OAD). The mean reduction in glycated hemoglobin appeared greater with liraglutide therapy, with the estimated mean treatment difference (95% confidence interval [CI]) for liraglutide vs additional OAD ranging from -0.14%, 95% CI: -0.48 to 0.21 (-1.5 mmol/mol, 95 CI: -5.2 to 2.3) to -0.44%, 95% CI:-0.79 to -0.09 (-4.8 mmol/mol, 95% CI: -8.6 to -1.0).

CONCLUSIONS

The present analysis suggests that Japanese patients on OAD monotherapy might benefit from a greater improvement in glycemic control, without impacting tolerability, by combining their OAD with liraglutide rather than another OAD, regardless of which OAD monotherapy they are receiving.

GLP-1 receptor agonists and heart failure in diabetes

The prevalence of heart failure (HF) is increasing in patients with type 2 diabetes (T2D), and glucose-lowering agents have distinctive effects on the risk of developing HF that requires hospitalization. Such an increased risk has been consistently reported with thiazolidinediones (glitazones) and perhaps also with the dipeptidyl peptidase (DPP)-4 inhibitor saxagliptin (at least in SAVOR - TIMI 53), whereas a markedly decreased risk was highlighted with the sodium - glucose cotransporter type 2 (SGLT2) inhibitor empagliflozin in EMPA-REG OUTCOME. Yet, the effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) on myocardial function remain controversial. Whereas some promising observations have been reported in various animal models, the effects of GLP-1RAs on myocardial function in humans are more heterogeneous, while the positive effect on left ventricular ejection fraction (LVEF), if any, appears to be inconsistent and rather modest in most patients with HF. However, no increased risk of hospitalization for HF has been reported with GLP-1RAs in meta-analyses of phase-II/III trials (exenatide, albiglutide, dulaglutide, liraglutide), demonstrating the safety of this pharmacological class, and such findings have been confirmed by three large prospective cardiovascular outcome trials (ELIXA with lixisenatide, LEADER with liraglutide and SUSTAIN-6 with semaglutide). In particular, LEADER reported a trend towards a reduction in HF hospitalization (-13%, P = 0.14), together with a significant reduction in cardiovascular and all-cause mortality in patients with T2D at risk of cardiovascular disease. These results are reassuring in the face of the somewhat negative results of the FIGHT trial, which evaluated the effects of liraglutide in patients with advanced HF and low LVEF, such that further studies and caution are now required when using this agent to treat such patients in clinical practice.

Clinical application of glucagon-like peptide-1 receptor agonists in cardiovascular disease: lessons from recent clinical cardiovascular outcomes trials

Recent clinical trials investigating cardiovascular (CV) safety of newer antidiabetic agents have been rapidly and largely changing the landscape of diabetes care and providing highly important clinical information on decision-making regarding the choice of antidiabetic agents. Similar to the sodium-glucose cotransporter 2 (SGLT2) inhibitors, some glucagon-like peptide-1 receptor agonists (GLP-1RAs) have also demonstrated a marked risk reduction in major adverse CV events (MACE) in patients with type 2 diabetes at high risk of CV events. However, the two classes of agents differ largely in their pharmacological modes of action on glucose-lowering and CV parameters. Furthermore, CV benefits on individual components of MACE and other outcomes, including heart failure (HF), appear to differ partly between the two classes. Specifically, improvement of overall CV outcomes was likely driven by reduction in HF-related events in trials investigating SGLT2 inhibitors, and by reduction in atherosclerotic events in those investigating GLP-1RAs. This difference in CV benefit observed in the trials has important clinical implications regarding how to use the two classes of agents and how to identify suitable patients to obtain the best benefit from each class during routine diabetes care, possibly leading to a treatment plan tailored to an individual patient’s CV risk and clinical condition. At this stage, however, we cardiologists may overlook such differences and may be unfamiliar with GLP-1RAs specifically. Herein, we highlight the potential benefits of GLP-1RAs on CV parameters observed in recent CV outcomes trials and further discuss clinical application of GLP-1RAs in CV medicine.

Characteristics of repaglinide effects on insulin secretion

The dynamics of insulin secretion stimulated by repaglinide, a glinide, and the combinatorial effects of repaglinide and incretin were investigated. At 4.4 mM glucose, repaglinide induced insulin secretion with a gradually increasing first phase, showing different dynamics from that induced by glimepiride, a sulfonylurea. In the presence of glucagon-like peptide-1 (GLP-1), insulin secretion by repaglinide was augmented significantly but to lesser extent and showed different dynamics from that by glimepiride. At 4.4 mM glucose, the intracellular Ca²⁺ level was gradually increased by repaglinide alone or repaglinide plus GLP-1, which differs from the Ca²⁺ dynamics by glimepiride alone or glimepiride plus GLP-1, suggesting that the difference in Ca²⁺ dynamics contributes to the difference in the dynamics of insulin secretion. At a higher concentration (8.8 mM) of glucose, the dynamics of insulin secretion stimulated by repaglinide was similar to that by glimepiride. Combination of repaglinide and GLP-1 significantly augmented insulin secretion, the amount of which was comparable to that by the combination of glimepiride and GLP-1. The Ca²⁺ dynamics was similar for repaglinide and glimepiride at 8.8 mM glucose. Our data indicate that repaglinide has characteristic properties in its effects on the dynamics of insulin secretion and intracellular Ca²⁺ and that the combination of repaglinide and GLP-1 stimulates insulin secretion more effectively than the combination of glimepiride and GLP-1 at a high concentration of glucose, providing a basis for its use in clinical settings.

Effect of race on the glycaemic response to sitagliptin: Insights from the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS)

AIM

Pooled efficacy studies suggest that glycaemic responses to dipeptidyl-peptidase 4 inhibitors in type 2 diabetes are greatest in Asians, who may also respond better to alpha-glucosidase inhibitors. We assessed the glycaemic impact of sitagliptin by race in the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS), and whether this was enhanced in Asians with concomitant acarbose therapy.

MATERIALS AND METHODS

TECOS enrolled 14 671 patients with type 2 diabetes, cardiovascular disease and HbA1c of 48-64 mmol/mol (6.5%-8.0%), and randomized them, double-blind, to sitagliptin or placebo. There were 3265 patients (22.3%) from Asian countries. Background glucose-lowering therapies were unaltered for the first 4 months post randomization unless clinically essential, facilitating comparison of sitagliptin-associated effects in self-identified East Asian, Other (South) Asian, White Caucasian, Hispanic, Black and Indigenous groups.

RESULTS

Median baseline HbA1c by race was 54 to 57 mmol/mol (7.1%-7.4%). Mean 4-month reduction in placebo-adjusted HbA1c was greatest in East Asians (-6.6 mmol/mol [-0.60%] vs ≤6.0 mmol/mol [≤0.55%] in other groups), with significantly greater reduction vs the 2 largest groups (White Caucasians, Other Asians; P < .0001) after adjustment for covariates. After the first 4 months, East and Other Asians were more likely to initiate additional oral therapy (metformin and/or sulfonylureas) than insulin vs White Caucasians (P < .0001). Acarbose use increased in the Asian patients, but no glycaemic interaction with allocated study medication was observed (adjusted P = .12).

CONCLUSIONS

The greatest initial reduction in HbA1c with sitagliptin in the TECOS population was in East Asians. No enhanced glycaemic effect was seen when sitagliptin was given with acarbose.

Altered glucose metabolism after bariatric surgery: What's GLP-1 got to do with it?

Bariatric surgery is an effective treatment for obesity. The two widely performed weight-loss procedures, Roux-en-Y gastric bypass (GB) and sleeve gastrectomy (SG), alter postprandial glucose pattern and enhance gut hormone secretion immediately after surgery before significant weight loss. This weight-loss independent glycemic effects of GB has been attributed to an accelerated nutrient transit from stomach pouch to the gut and enhanced secretion of insulinotropic gut factors; in particular, glucagon-like peptide-1 (GLP-1). Meal-induced GLP-1 secretion is as much as tenfold higher in patients after GB compared to non-surgical individuals and inhibition of GLP-1 action during meals reduces postprandial hyperinsulinemia after GB two to three times more than that in persons without surgery. Moreover, in a subgroup of patients with the late complication of postprandial hyperinsulinemic hypoglycemia after GB, GLP1R blockade reverses hypoglycemia by reducing meal stimulated insulin secretion. The role of enteroinsular axis activity after SG, an increasingly popular alternative to GB, is less understood but, similar to GB, SG accelerates nutrient delivery to the intestine, improves glucose tolerance, and increases postprandial GLP-1 secretion. This review will focus on the current evidence for and against the role of GLP-1 on glycemic effects of GB and will also highlight differences between GB and SG.

Effects of linagliptin on endothelial function and postprandial lipids in coronary artery disease patients with early diabetes: a randomized, placebo-controlled, double-blind trial

Background

Early glucose lowering intervention in subjects with type 2 diabetes mellitus was demonstrated to be beneficial in terms of micro- and macrovascular risk reduction. However, most of currently ongoing cardiovascular outcome trials are performed in subjects with manifest atherosclerosis and long-standing diabetes. Therefore, the aim of this study is to investigate the effects of the dipeptidylpeptidase-4 inhibitor linagliptin in subjects with coronary artery disease (CAD) but early type 2 diabetes mellitus (T2DM) on a set of cardiovascular surrogate measurements.

Methods

In this randomized, placebo-controlled, double-blind, single-center study, we included subjects with early diabetes (postchallenge diabetes (2 h glucose > 200 mg/dl) or T2DM treated with diet only or on a stable dose of metformin monotherapy and an HbA1c < 75 mmol/mol) and established CAD. Participants were randomized to receive either linagliptin (5 mg) once daily orally or placebo for 12 weeks. The primary outcome was the change in flow mediated dilatation (FMD). The secondary objective was to investigate the effect of linagliptin treatment on arginine bioavailability ratios [Global arginine bioavailability ratio (GABR) and arginine to ornithine ratio (AOR)]. Arginine, ornithine and citrulline were measured in serum samples with a conventional usual amino acid analysis technique, involving separation of amino acids by ion exchange chromatography followed by postcolumn continuous reaction with ninhydrin. GABR was calculated by l-arginine divided by the sum of (l-ornithine plus l-citrulline). The AOR was calculated by dividing l-arginine by l-ornithine levels. Group comparisons were calculated by using a two-sample t-test with Satterthwaite adjustment for unequal variances.

Results

We investigated 43 patients (21% female) with a mean age of 63.3 ± 8.2 years. FMD at baseline was 3.5 ± 3.1% in the linagliptin group vs. 4.0 ± 2.9% in the placebo group. The change in mean FMD in the linagliptin group was not significantly different compared to the change in the placebo group (0.43 ± 4.84% vs. − 0.45 ± 3.01%; p = 0.486). No significant improvements were seen in the arginine bioavailability ratios (GABR; p = 0.608 and AOR; p = 0.549).

Conclusion

Linagliptin treatment in subjects with CAD and early T2DM did not improve endothelial function or the arginine bioavailability ratios.

Trial registration ClinicalTrials.gov, NCT02350478 (https://clinicaltrials.gov/ct2/show/NCT02350478)

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0716-x) contains supplementary material, which is available to authorized users.