Cholecystokinin secretion is suppressed by glucagon-like peptide-1: clue to the mechanism of the adverse gallbladder events of GLP-1-derived drugs

A review of serious adverse events linked with GLP-1 agonists in type 2 diabetes mellitus and obesity treatment

Glucagon-like peptide-1 (GLP-1) agonists play a crucial role in treating type 2 diabetes mellitus and obesity by providing glycemic control and aiding weight management. Despite their widespread use, concerns about serious adverse events have prompted extensive research. This review aims to describe the current understanding of serious adverse events associated with GLP-1 agonists. A comprehensive search of PubMed, Google Scholar and Embase databases was performed starting from 2010. Studies reporting evidence of an association between GLP-1 agonists and serious adverse events from 22 articles (5 case reports, 5 randomized controlled trials (RCTs), 9 real-world data cohort analyses, 2 meta-analyses and 1 systematic review and meta-analysis) were included and categorized by the type of adverse event. While some studies reported risks, including anaphylaxis, cardiovascular, gastrointestinal, psychiatric and thyroid-related events, others found no significant associations. The evidence remains mixed, necessitating further research to fully understand the safety profile of GLP-1 agonists and inform clinical practice.

Assessing the therapeutic and toxicological profile of novel GLP-1 receptor agonists for type 2 diabetes

INTRODUCTION

GLP-1 receptor agonists provide multiple benefits for patients with type 2 diabetes. Nonetheless, there are also several significant adverse effects associated with these agents. A thorough understanding of both therapeutic and toxicological profiles of GLP-1 receptor agonists is crucial for appropriate utilization of this medication class. A literature search of PubMed and ClinicalTrials.gov was carried out to inform discussion on the topic.

AREAS COVERED

This review article discusses the key advantages and disadvantages derived from the use of GLP-1 receptor agonists in the treatment of type 2 diabetes. Landmark trials which helped characterize the cardiovascular and renal benefits of GLP-1 receptor agonists are highlighted. We also discuss key studies still in progress and new formulations under investigation.

EXPERT OPINION

GLP-1 receptor agonists provide glycemic and complication-risk reduction benefits for individuals with type 2 diabetes. Current data suggests there is a lot of potential for further applications, even outside of type 2 diabetes management. It would be of particular interest to see the range of benefits conferred from GLP-1 receptor agonists in individuals without type 2 diabetes. Broader application of these medications could be expected given the ongoing development of new oral formulations and combination agents.

The real-world safety profile of tirzepatide: pharmacovigilance analysis of the FDA Adverse Event Reporting System (FAERS) database

PURPOSE

Randomized controlled trials with tirzepatide (TZP) displayed unprecedented glucose and body weight lowering efficacy in individuals with type 2 diabetes and/or obesity and a safety profile similar to that of glucagon-like peptide-1 receptor agonists (GLP-1RA), mainly characterized by gastrointestinal (GI) adverse events (AE). Concerns on diabetic retinopathy, pancreato-biliary disorders, and medullary thyroid cancer were also addressed. We aimed to investigate whether the same safety issues emerged from the FDA Adverse Event Reporting System (FAERS) post-marketing surveillance database.

METHODS

OpenVigil 2.1-MedDRA-v24 and AERSMine (data 2004Q1-2023Q3) were used to query the FAERS database. Reports of GI AE, diabetic retinopathy, pancreato-biliary disorders, and medullary thyroid cancer were investigated. The analysis was then filtered for age, gender, and designation as primary suspect. AE occurrence with TZP was compared to insulin, sodium-glucose cotransporter-2 inhibitors, metformin, and GLP-1RA.

RESULTS

Disproportionate reporting of GI [i.e., nausea (ROR 4.01, 95% CI 3.85-4.19)] and pancreato-biliary disorders [i.e., pancreatitis (ROR 3.63, 95% CI 3.15-4.19)], diabetic retinopathy (ROR 4.14, 95% CI 2.34-7.30), and medullary thyroid cancer (ROR 13.67, 95% CI 4.35-42.96) was detected. TZP exhibited a similar risk of GI AE and medullary thyroid cancer and a lower risk of most pancreato-biliary AE and diabetic retinopathy vs. GLP-1RA.

CONCLUSIONS

TZP was associated with an increased risk of specific AE. However, its safety profile was similar to that of GLP-1RA, without increased risk of pancreato-biliary AE, diabetic retinopathy, and medullary thyroid cancer.

Dipeptidyl Peptidase-4 Inhibitors and the Risk of Gallbladder and Bile Duct Disease Among Patients with Type 2 Diabetes: A Population-Based Cohort Study

INTRODUCTION

The use of dipeptidyl peptidase-4 (DPP-4) inhibitors may be associated with an increased risk of gallbladder and bile duct disease among patients with type 2 diabetes.

METHODS

We conducted a population-based cohort study using an active comparator, new-user design. We used data from the United Kingdom Clinical Practice Research Datalink to identify patients newly treated with either a DPP-4 inhibitor or sodium-glucose cotransporter-2 (SGLT-2) inhibitor between January 2013 and December 2020. We fitted Cox proportional hazards models with propensity score fine stratification weighting to estimate the hazard ratio (HR) and its 95% confidence interval (CI) for incident gallbladder and bile duct disease associated with DPP-4 inhibitors compared to SGLT-2 inhibitors.

RESULTS

DPP-4 inhibitors were associated with a 46% increased risk of gallbladder and bile duct disease (4.3 vs. 3.0 events per 1000 person-years, HR 1.46, 95% CI 1.17-1.83). At 6 months and 1 year, 745 and 948 patients, respectively, would need to be treated with DPP-4 inhibitors for one patient to experience a gallbladder or bile duct disease.

CONCLUSIONS

In this population-based cohort study, the use of DPP-4 inhibitors, when compared with SGLT-2 inhibitors, was associated with a moderately increased risk of gallbladder and bile duct disease among patients with type 2 diabetes. This outcome was still quite rare with a high number needed to harm at 6 months and 1 year.

The preclinical discovery and clinical evaluation of tirzepatide for the treatment of type 2 diabetes

INTRODUCTION

Despite numerous antidiabetic medications available for the treatment of type 2 diabetes, a substantial percentage of patients fail to achieve optimal glycemic control. Furthermore, the escalating obesity pandemic underscores the urgent need for effective relevant pharmacotherapies. Tirzepatide, a novel dual GIP and GLP-1 receptor agonist, offers a promising therapeutic option.

AREAS COVERED

This review describes the discovery and clinical development of tirzepatide. Based on data from pivotal in vivo and in vitro studies, the authors present the pharmacodynamic profile of tirzepatide. Furthermore, they summarize data from the clinical trial programs that assessed the efficacy and safety of tirzepatide for the treatment of type 2 diabetes or obesity in a broad spectrum of patients, and discuss its therapeutic potential.

EXPERT OPINION

Tirzepatide effectively reduces glucose levels and body weight in patients with type 2 diabetes and/or obesity, with a generally safe profile. Based on data from phase 3 clinical trials, several agencies have approved its use for the treatment of type 2 diabetes and obesity. Clinicians should be aware of possible adverse events, mainly mild-to-moderate gastrointestinal side effects. Overall, tirzepatide represents a promising treatment option for the treatment of type 2 diabetes.

Colesevelam has no acute effect on postprandial GLP-1 levels but abolishes gallbladder refilling

OBJECTIVE

Colesevelam, a bile acid sequestrant approved for the treatment of hypercholesterolaemia, improves glycaemic control in type 2 diabetes. We hypothesised that single-dose colesevelam increases postprandial GLP-1 secretion, thus, reducing postprandial glucose excursions in individuals with type 2 diabetes. Further, we explored the effects of single-dose colesevelam on ultrasonography-assessed postprandial gallbladder motility, paracetamol absorption (proxy for gastric emptying), and circulating factors known to affect gallbladder motility.

METHODS

In a randomised, double-blind, placebo-controlled crossover study, 12 individuals with type 2 diabetes (mean ± SD: age 61 ± 8.8 years; body mass index 29.8 ± 3.0 kg/m2) were subjected to 4 mixed meal tests on separate days; 2 with orally administered colesevelam (3.75 g) and 2 with placebo, with intravenous infusion of the GLP-1 receptor antagonist exendin(9-39)NH2 or saline.

RESULTS

Single-dose colesevelam had no effect on postprandial concentrations of glucose (P = .786), C-peptide (P = .440), or GLP-1 (P = .729), and exendin(9-39)NH2 administration revealed no GLP-1-mediated effects of colesevelam. Colesevelam did not affect gallbladder emptying but abolished gallbladder refilling (P = .001), increased postprandial cholecystokinin (CCK) secretion (P = .010), and decreased postprandial serum concentrations of fibroblast growth factor 19 (FGF19) (P = .035) and bile acids (P = .043).

CONCLUSION

Single-dose colesevelam had no effect on postprandial GLP-1 responses or glucose tolerance but disrupted postprandial gallbladder refilling by increasing CCK secretion and reducing circulating concentrations of FGF19 and bile acids. These findings leave the antidiabetic actions of colesevelam unresolved but provide mechanistic insights into its effect on gallbladder motility.

Liver biopsy for assessment of suspected drug-induced liver injury in metabolic dysfunction-associated steatohepatitis clinical trials: Expert consensus from the Liver Forum

BACKGROUND

Causality assessment of suspected drug-induced liver injury (DILI) during metabolic dysfunction-associated steatohepatitis (MASH) clinical trials can be challenging, and liver biopsies are not routinely performed as part of this evaluation. While the field is moving away from liver biopsy as a diagnostic and prognostic tool, information not identified by non-invasive testing may be provided on histology.

AIM

To address the appropriate utilisation of liver biopsy as part of DILI causality assessment in this setting.

METHODS

From 2020 to 2022, the Liver Forum convened a series of webinars on issues pertaining to liver biopsy during MASH trials. The Histology Working Group was formed to generate a series of consensus documents addressing these challenges. This manuscript focuses on liver biopsy as part of DILI causality assessment.

RESULTS

Expert opinion, guidance and recommendations on the role of liver biopsy as part of causality assessment of suspected DILI occurring during clinical trials for a drug(s) being developed for MASH are provided. Lessons learned from prior MASH programs are reviewed and gaps identified.

CONCLUSIONS

Although there are no pathognomonic features, histologic evaluation of suspected DILI during MASH clinical trials may alter patient management, define the pattern and severity of injury, detect findings that favour a diagnosis of DILI versus MASH progression, identify prognostic features, characterise the clinicopathological phenotype of DILI, and/or define lesions that influence decisions about trial discontinuation and further development of the drug.

Biology and Clinical Use of Glucagon-Like Peptide-1 Receptor Agonists in Vascular Protection

Glucagon-like peptide-1 receptor agonists (GLP1RA) are incretin agents initially designed for the treatment of type 2 diabetes mellitus but because of pleiotropic actions are now used to reduce cardiovascular disease in people with type 2 diabetes mellitus and in some instances as approved treatments for obesity. In this review we highlight the biology and pharmacology of GLP1RA. We review the evidence for clinical benefit on major adverse cardiovascular outcomes in addition to modulation of cardiometabolic risk factors including reductions in weight, blood pressure, improvement in lipid profiles, and effects on kidney function. Guidance is provided on indications and potential adverse effects to consider. Finally, we describe the evolving landscape of GLP1RA and including novel glucagon-like peptide-1-based dual/polyagonist therapies that are being evaluated for weight loss, type 2 diabetes mellitus, and cardiorenal benefit.

Safety issues of tirzepatide (pancreatitis and gallbladder or biliary disease) in type 2 diabetes and obesity: a systematic review and meta-analysis

Purpose

A systematic review and meta-analysis was conducted to synthesize the available data from clinical trials and assess the safety issues of tirzepatide (pancreatitis and gallbladder or biliary disease) in type 2 diabetes (T2D) and obesity.

Methods

A systematic search was conducted in three electronic databases, namely Embase, PubMed, and the Cochrane Library, up until March 1, 2023, to identify randomized controlled trials (RCTs) comparing tirzepatide to either placebo or active hypoglycemic drugs in individuals with T2D and obesity. Heterogeneity was assessed using the I2 value and Cochran's Q test, and a fixed effects model was employed to estimate the safety profile of tirzepatide. The safety outcomes of interest, including pancreatitis, the composite of gallbladder or biliary diseases, cholecystitis, and cholelithiasis and biliary diseases, were evaluated. (The composite of gallbladder or biliary diseases incorporated cholelithiasis, cholecystitis, other gallbladder disorders, and biliary diseases.).

Results

A total of nine trials with 9871 participants (6828 in the tirzepatide group and 3043 in the control group) that met the pre-specified criteria were included. When compared to all control groups consisting of basal insulin (glargine or degludec), selective GLP1-RA (dulaglutide or semaglutide once weekly), and placebo, an increased risk of pancreatitis was not found to be significantly associated with tirzepatide (RR 1.46, [95% CI] 0.59 to 3.61; I2 = 0.0%, p = 0.436). For gallbladder or biliary disease, the composite of gallbladder or biliary disease was significantly associated with tirzepatide compared with placebo or basal insulin (RR 1.97, [95% CI] 1.14 to 3.42; I2 = 0.0%, p = 0.558), but not with the risk of cholelithiasis, cholecystitis or biliary diseases.

Conclusion

Based on the currently available data, tirzepatide appears to be safe regarding the risk of pancreatitis. However, the increased risk of the composite outcome of gallbladder or biliary diseases observed in RCTs warrants further attention from physicians in clinical practice.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023412400.

Liraglutide changes postprandial responses of gut hormones involved in the regulation of gallbladder motility

AIM

Liraglutide treatment is associated with gallbladder-related disorders and has been shown to delay postprandial gallbladder refilling. The gut hormones cholecystokinin (CCK), fibroblast growth factor 19 (FGF19) and glucagon-like peptide 2 (GLP-2), are known to regulate gallbladder motility and may be implicated in gallbladder-related disorders associated with liraglutide treatment.

MATERIALS AND METHODS

In a double-blind, 12-week trial, 52 participants [50% male, age 47.6 ± 10.0 years, body mass index 32.6 ± 3.4 kg/m² (mean ± standard deviation)] with obesity were randomized 1:1 to once-daily subcutaneous liraglutide (escalated from 0.6 mg to 3.0 mg once-daily) or placebo. During liquid meal tests performed at baseline, after the first dose and following 12 weeks of treatment, we evaluated postprandial gallbladder dynamics and plasma responses of CCK, FGF19 and GLP-2.

RESULTS

Liraglutide reduced postprandial FGF19 after the first dose [area under the curve (AUC)_{0-240 min} 24.8 vs. 48.0 min × ng/ml, treatment ratio (TR) (95% confidence interval) 0.52 (0.39; 0.69)] and following 12 weeks of treatment [AUC_{0-240 min} 33.7 vs. 48.5 ng/ml × min, TR 0.69 (0.52; 0.93)]. Liraglutide also reduced postprandial GLP-2 responses (AUC_{0-240 min} 3650 vs. 4894 min × pmol/L, TR 0.75 (0.62; 0.90)] following the first dose as well as after 12 weeks [AUC_{0-240 min} 3760 vs. 4882 min × pmol/L, TR 0.77 (0.60; 0.99)]. Liraglutide increased postprandial responses of CCK after the first dose [AUC_{0-240 min} 762 vs. 670 min × pmol/L; TR 1.14 (0.97; 1.33)] and following 12 weeks of treatment [AUC_{0-240 min} 873 vs. 628 min × pmol/L; TR 1.39 (1.12; 1.73)].

CONCLUSION

Compared with placebo, treatment with liraglutide decreased postprandial FGF19 and GLP-2 concentrations and increased postprandial CCK concentrations, which may explain the delayed postprandial gallbladder refilling observed in individuals with obesity treated with liraglutide.

Acute Cholecystitis Associated With the Use of Glucagon-Like Peptide-1 Receptor Agonists Reported to the US Food and Drug Administration

This case series identifies cases reported in the US Food and Drug Administration Adverse Event Reporting System of acute cholecystitis associated with use of glucagon-like peptide-1 receptor agonists that did not have gallbladder disease warnings in their labeling.

The role of insulin and incretin-based drugs in biliary tract cancer: epidemiological and experimental evidence

Insulin and incretin-based drugs are important antidiabetic agents with complex effects on cell growth and metabolism. Emerging evidence shows that insulin and incretin-based drugs are associated with altered risk of biliary tract cancer (BTC). Observational study reveals that insulin is associated with an increased risk of extrahepatic cholangiocarcinoma (ECC), but not intrahepatic cholangiocarcinoma (ICC) or gallbladder cancer (GBC). This type-specific effect can be partly explained by the cell of origin and heterogeneous genome landscape of the three subtypes of BTC. Similar to insulin, incretin-based drugs also exhibit very interesting contradictions and inconsistencies in response to different cancer phenotypes, including BTC. Both epidemiological and experimental evidence suggests that incretin-based drugs can be a promoter of some cancers and an inhibitor of others. It is now more apparent that this type of drugs has a broader range of physiological effects on the body, including regulation of endoplasmic reticulum stress, autophagy, metabolic reprogramming, and gene expression. In particular, dipeptidyl peptidase-4 inhibitors (DPP-4i) have a more complex effect on cancer due to the multi-functional nature of DPP-4. DPP-4 exerts both catalytic and non-enzymatic functions to regulate metabolic homeostasis, immune reaction, cell migration, and proliferation. In this review, we collate the epidemiological and experimental evidence regarding the effect of these two classes of drugs on BTC to provide valuable information.

Dipeptidyl peptidase-4 inhibitors and gallbladder or biliary disease in type 2 diabetes: systematic review and pairwise and network meta-analysis of randomised controlled trials

OBJECTIVE

To examine the association between dipeptidyl peptidase-4 inhibitors and gallbladder or biliary diseases.

DESIGN

Systematic review and pairwise and network meta-analysis.

DATA SOURCES

PubMed, EMBASE, Web of Science, and CENTRAL from inception until 31 July 2021.

ELIGIBILITY CRITERIA

Randomised controlled trials of adult patients with type 2 diabetes who received dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter-2 inhibitors compared with placebo or other antidiabetes drugs.

MAIN OUTCOME MEASURES

Composite of gallbladder or biliary diseases, cholecystitis, cholelithiasis, and biliary diseases.

DATA EXTRACTION AND DATA SYNTHESIS

Two reviewers independently extracted the data and assessed the quality of the studies. The quality of the evidence for each outcome was assessed using the Grading of Recommendations, Assessment, Development and Evaluations framework (GRADE) approach. The meta-analysis used pooled odds ratios and 95% confidence intervals.

RESULTS

A total of 82 randomised controlled trials with 104 833 participants were included in the pairwise meta-analysis. Compared with placebo or non-incretin drugs, dipeptidyl peptidase-4 inhibitors were significantly associated with an increased risk of the composite of gallbladder or biliary diseases (odds ratio 1.22 (95%confidence interval 1.04 to 1.43); risk difference 11 (2 to 21) more events per 10 000 person years) and cholecystitis (odds ratio 1.43 (1.14 to 1.79); risk difference 15 (5 to 27) more events per 10 000 person years) but not with the risk of cholelithiasis and biliary diseases. The associations tended to be observed in patients with a longer duration of dipeptidyl peptidase-4 inhibitor treatment. In the network meta-analysis of 184 trials, dipeptidyl peptidase-4 inhibitors increased the risk of the composite of gallbladder or biliary diseases and cholecystitis compared with sodium-glucose cotransporter-2 inhibitors but not compared with glucagon-like peptide-1 receptor agonists.

CONCLUSIONS

Dipeptidyl peptidase-4 inhibitors increased the risk of cholecystitis in randomised controlled trials, especially with a longer treatment duration, which requires more attention from physicians in clinical practice.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021271647.

Association of Glucagon-Like Peptide-1 Receptor Agonist Use With Risk of Gallbladder and Biliary Diseases: A Systematic Review and Meta-analysis of Randomized Clinical Trials

IMPORTANCE

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been widely recommended for glucose control and cardiovascular risk reduction in patients with type 2 diabetes, and more recently, for weight loss. However, the associations of GLP-1 RAs with gallbladder or biliary diseases are controversial.

OBJECTIVE

To evaluate the association of GLP-1 RA treatment with gallbladder and biliary diseases and to explore risk factors for these associations.

DATA SOURCES

MEDLINE/PubMed, EMBASE, Web of Science, and Cochrane Library (inception to June 30, 2021), websites of clinical trial registries (July 10, 2021), and reference lists. There were no language restrictions.

STUDY SELECTION

Randomized clinical trials (RCTs) comparing the use of GLP-1 RA drugs with placebo or with non-GLP-1 RA drugs in adults.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently extracted data according to the PRISMA recommendations and assessed the quality of each study with the Cochrane Collaboration risk-of-bias tool. Pooled relative risks (RRs) were calculated using random or fixed-effects models, as appropriate. The quality of evidence for each outcome was assessed using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework.

MAIN OUTCOMES AND MEASURES

The primary outcome was the composite of gallbladder or biliary diseases. Secondary outcomes were biliary diseases, biliary cancer, cholecystectomy, cholecystitis, and cholelithiasis. Data analyses were performed from August 5, 2021, to September 3, 2021.

RESULTS

A total of 76 RCTs involving 103 371 patients (mean [SD] age, 57.8 (6.2) years; 41 868 [40.5%] women) were included. Among all included trials, randomization to GLP-1 RA treatment was associated with increased risks of gallbladder or biliary diseases (RR, 1.37; 95% CI, 1.23-1.52); specifically, cholelithiasis (RR, 1.27; 95% CI, 1.10-1.47), cholecystitis (RR, 1.36; 95% CI, 1.14-1.62), and biliary disease (RR, 1.55; 95% CI, 1.08-2.22). Use of GLP-1 RAs was also associated with increased risk of gallbladder or biliary diseases in trials for weight loss (n = 13; RR, 2.29; 95% CI, 1.64-3.18) and for type 2 diabetes or other diseases (n = 63; RR, 1.27; 95% CI, 1.14-1.43; P <.001 for interaction). Among all included trials, GLP-1 RA use was associated with higher risks of gallbladder or biliary diseases at higher doses (RR, 1.56; 95% CI, 1.36-1.78) compared with lower doses (RR, 0.99; 95% CI, 0.73-1.33; P  = .006 for interaction) and with longer duration of use (RR, 1.40; 95% CI, 1.26-1.56) compared with shorter duration (RR, 0.79; 95% CI, 0.48-1.31; P  = .03 for interaction).

CONCLUSIONS AND RELEVANCE

This systematic review and meta-analysis of RCTs found that use of GLP-1 RAs was associated with increased risk of gallbladder or biliary diseases, especially when used at higher doses, for longer durations, and for weight loss.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42021271599.

Role of cholecystokinin and oxytocin in slower gastric emptying induced by physical exercise in rats

Vigorous exercise can induce gastrointestinal disorders such decreased gastric emptying pace, while low-intensity exercise can accelerate gastric motility. However, the mechanisms of these effects are still unknown. We investigated the possible neurohumoral mechanisms involved in these phenomena. In sedentary (Sed) and acute exercise (Ex) groups of rats, we assessed the activation of c-Fos in NTS and DVMN and the plasma levels of CCK and OXT. Separate groups received pretreatment with the oxytocin antagonist atosiban (AT), the cholecystokinin antagonist devazepide (DVZ), or the TRPV1 receptor inhibitor capsazepine (CAPZ). AT, DVZ and CAPZ treatments prevented (p<0.05) slower gastric emptying induced by acute exercise. The gene expression of OXT decreased (P<0.05) while that of CCK increased (P<0.05) in the gastric fundus and pylorus of the Ex group, while the plasma levels of OXT rose (p<0.05) and of CCK declined (p<5.05). We also observed activation (p<0.05) of c-Fos-sensitive neurons in the NTS and DVMN of exercised rats. In conclusion, acute exercise slowed gastric emptying by the vagal afferent pathway, which involved activation of CCK1/OXT/TRPV1 sensitivity.

Side Effects Associated with Liraglutide Treatment for Obesity as Well as Diabetes

Liraglutide is a glucagon-like peptide-1 receptor agonist used as a treatment for type 2 diabetes mellitus, which has been expanded for use at a higher dose in weight control. Therefore, it is necessary to consider adverse reactions of the drug at high doses as well as at lower doses after the indication has been expanded. Body mass index criteria for patients prescribed the drug in the real world tend to be applied less rigorously, which may increase the number of adverse reactions due to over-prescription. Liraglutide treatment was found effective and safe in some studies, while others have warned about its risks. Therefore, this review summarizes the current data available on side effects associated with liraglutide.

Benefits of Sustained Upregulated Unimolecular GLP-1 and CCK Receptor Signalling in Obesity-Diabetes

Combined activation of GLP-1 and CCK1 receptors has potential to synergistically augment the appetite-suppressive and glucose homeostatic actions of the individual parent peptides. In the current study, pancreatic beta-cell benefits of combined GLP-1 and CCK1 receptor upregulation were established, before characterising bioactivity and antidiabetic efficacy of an acylated dual-acting GLP-1/CCK hybrid peptide, namely [Lys¹²Pal]Ex-4/CCK. Both exendin-4 and CCK exhibited (p<0.001) proliferative and anti-apoptotic effects in BRIN BD11 beta-cells. Proliferative benefits were significantly (p<0.01) augmented by combined peptide treatment when compared to either parent peptide alone. These effects were linked to increases (p<0.001) in GLUT2 and glucokinase beta-cell gene expression, with decreased (p<0.05-p<0.001) expression of NFκB and BAX. [Lys¹²Pal]Ex-4/CCK exhibited prominent insulinotropic actions in vitro, coupled with beneficial (p<0.001) satiety and glucose homeostatic effects in the mice, with bioactivity evident 24 h after administration. Following twice daily injection of [Lys¹²Pal]Ex-4/CCK for 28 days in diabetic high fat fed (HFF) mice with streptozotocin (STZ)-induced compromised beta-cells, there were clear reductions (p<0.05-p<0.001) in energy intake and body weight. Circulating glucose was returned to lean control concentrations, with associated increases (p<0.001) in plasma and pancreatic insulin levels. Glucose tolerance and insulin secretory responsiveness were significantly (p<0.05-p<0.001) improved by hybrid peptide therapy. In keeping with this, evaluation of pancreatic histology revealed restoration of normal islet alpha- to beta-cell ratios and reduction (p<0.01) in centralised islet glucagon staining. Improvements in pancreatic islet morphology were associated with increased (p<0.05) proliferation and reduced (p<0.001) apoptosis of beta-cells. Together, these data highlight the effectiveness of sustained dual GLP-1 and CCK1 receptor activation by [Lys¹²Pal]Ex-4/CCK for the treatment of obesity-related diabetes.

Multiagonist Unimolecular Peptides for Obesity and Type 2 Diabetes: Current Advances and Future Directions

The ever-increasing prevalence of obesity and Type 2 diabetes has necessitated the development of newer and more effective approaches for achieving efficient glycemic control and weight loss. Conventional treatment methods often result in weight gain, further deteriorating the already impaired metabolic control in people with obesity/Type 2 diabetes. Alleviation of obesity and diabetes achieved after bariatric surgeries highlight the therapeutic importance of gut-brain axis and entails development of more patient-friendly approaches replicating the positive metabolic effects of bariatric surgery. Given the potential involvement of several gut hormones in the success of bariatric surgery, the therapeutic importance of synergistic interaction between these hormones for improved metabolism cannot be ignored. Many unimolecular multiagonist peptides are in preclinical and clinical trials as they maximize the combinatorial metabolic efficacy by concurrent activation of multiple gut hormone receptors. This review summarizes the ongoing developments of multiagonist peptides as novel therapeutic approaches against obesity-diabetes.

The Role of Diabetes Mellitus in Diseases of the Gallbladder and Biliary Tract

BACKGROUND

The increasing prevalence of diabetes mellitus worldwide continues to pose a heavy burden. Though its gastrointestinal impact is appropriately recognized, the lesser known associations may be overlooked.

OBJECTIVE

We aim to review the negative implications of diabetes on the gallbladder and the biliary tract.

METHODS

A MEDLINE® database search of literature was conducted with emphasis on the previous five years, combining keywords such as "diabetes," "gallbladder," and "biliary".

RESULTS

The association of diabetes to the formation of gallstones, gallbladder cancer, and cancer of the biliary tract are discussed along with diagnosis and treatment.

CONCLUSION

Though we uncover the role of diabetic neuropathy in gallbladder and biliary complications, the specific individual diabetic risk factors behind these developments is unclear. Also, in addition to diabetes control and surgical gallbladder management, the treatment approach also requires further focus.

Gastrin secretion in normal subjects and diabetes patients is inhibited by glucagon-like peptide 1: a role in the gastric side effects of GLP-1-derived drugs?

Background: Randomized and controlled trials of glucagon-like peptide-1 (GLP-1) derived drugs have shown that the most frequent adverse symptoms are gastrointestinal. Some of the side effects such as dyspepsia, nausea and upper abdominal pain may well be of gastric origin. Since the antral hormone gastrin regulates gastric secretion of acid and enzymes and contributes to the regulation of gastric motility, we examined the effect of GLP-1 on the secretion of gastrin in normal subjects and diabetes patients.Method: Plasma was sampled from ten healthy subjects and ten patients with diabetes mellitus type 1 with glucose clamped between 6 and 9 mM. GLP-1 or saline were infused for 4 h during and after a meal. Plasma concentrations of gastrin and GLP-1 were measured using specific radioimmunoassays.Results: Basal plasma concentrations of gastrin were similar in controls and patients. After the meal, the gastrin concentrations rose significantly during saline infusion, whereas the GLP-1 infusion suppressed the secretion of gastrin significantly, most pronounced in the diabetes patients.Conclusions: The results show that GLP-1 infusion suppresses the postprandial secretion of gastrin in normal subjects and even more so in the diabetes patients. The results may therefore shed further light on the upper gastrointestinal side effects of GLP-1-derived drugs in diabetic patients.

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

OBJECTIVE

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

RESEARCH DESIGN AND METHODS

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

RESULTS

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

CONCLUSIONS

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