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

AIM

To investigate the changes of circulating levels of all proglucagon-derived peptides (PGDPs) in individuals with overweight or obesity receiving liraglutide (3 mg) or naltrexone/bupropion (32/360 mg), and to explore the association between induced changes in postprandial PGDP levels and body composition, as well as metabolic variables, after 3 and 6 months on treatment.

MATERIALS AND METHODS

Seventeen patients with obesity or with overweight and co-morbidities, but without diabetes, were assigned to receive once-daily oral naltrexone/bupropion 32/360 mg (n = 8) or once-daily subcutaneous liraglutide 3 mg (n = 9). Participants were assessed before treatment initiation and after 3 and 6 months on treatment. At the baseline and 3-month visits, participants underwent a 3-hour mixed meal tolerance test to measure fasting and postprandial levels of PGDPs, C-peptide, hunger and satiety. Clinical and biochemical indices of metabolic function, magnetic resonance-assessed liver steatosis and ultrasound-assessed liver stiffness were measured at each visit.

RESULTS

Both medications improved body weight and composition, carbohydrate and lipid metabolism, and liver fat and function. Naltrexone/bupropion produced a weight-independent increase in the levels of proglucagon (P < .001) and decreases in glucagon-like peptide-2 (GLP-2), glucagon and the major proglucagon fragment (P ≤ .01), whereas liraglutide markedly upregulated total glucagon-like peptide-1 (GLP-1) levels in a weight-independent manner (P = .04), and similarly downregulated the major proglucagon fragment, GLP-2 and glucagon (P < .01). PGDP levels at the 3-month visit were positively and independently correlated with improvements in fat mass, glycaemia, lipaemia and liver function, and negatively with reductions in fat-free mass, at both the 3- and 6-month visits.

CONCLUSIONS

PGDP levels in response to liraglutide and naltrexone/bupropion are associated with improvements in metabolism. Our study provides support for the administration of the downregulated members of the PGDP family as replacement therapy (e.g. glucagon), in addition to the medications currently in use that induced their downregulation (e.g. GLP-1), and future studies should explore whether the addition of other PGDPs (e.g. GLP-2) could offer additional benefits.

Diabetic Nephropathy: Update on Pillars of Therapy Slowing Progression

Management of diabetic kidney disease (DKD) has evolved in parallel with our growing understanding of the multiple interrelated pathophysiological mechanisms that involve hemodynamic, metabolic, and inflammatory pathways. These pathways and others play a vital role in the initiation and progression of DKD. Since its initial discovery, the blockade of the renin-angiotensin system has remained a cornerstone of DKD management, leaving a large component of residual risk to be dealt with. The advent of sodium-glucose cotransporter 2 inhibitors followed by nonsteroidal mineralocorticoid receptor antagonists and, to some extent, glucagon-like peptide 1 receptor agonists (GLP-1 RAs) has ushered in a resounding paradigm shift that supports a pillared approach in maximizing treatment to reduce outcomes. This pillared approach is like that derived from the approach to heart failure treatment. The approach mandates that all agents that have been shown in clinical trials to reduce cardiovascular outcomes and/or mortality to a greater extent than a single drug class alone should be used in combination. In this way, each drug class focuses on a specific aspect of the disease's pathophysiology. Thus, in heart failure, β-blockers, sacubitril/valsartan, a mineralocorticoid receptor antagonist, and a diuretic are used together. In this article, we review the evolution of the pillar concept of therapy as it applies to DKD and discuss how it should be used based on the outcome evidence. We also discuss the exciting possibility that GLP-1 RAs may be an additional pillar in the quest to further slow kidney disease progression in diabetes.

Denosumab Improves Glycaemic Parameters in Postmenopausal Osteoporosis Patients with Combined Type 2 Diabetes Mellitus

This study aimed to determine whether RANKL inhibitors in postmenopausal osteoporosis patients with combined type 2 diabetes mellitus (T2DM) could improve their glucose metabolism index. First of all, 84 patients affected with postmenopausal osteoporosis with combined T2DM attending the Department of Endocrinology at the Third Hospital of Hebei Medical University were selected and randomized into two groups of 42 patients each. One group was given Denosumab 60 mg once every six months (denosumab group, D.G.), and the other group was given 2 mg ibandronate once every three months (ibandronate group, I.G.). Blood glucose parameters were compared before and after treatment in both groups and serum active GLP-1 levels and DPP-4 levels were also assessed. After treatment, there was no significant difference in fasting glucose between the two groups, but there was a significant decrease in fasting glucose in the Denosumab Group (D.G.) compared to before treatment. There was a significant difference in 2-hour postprandial glucose (2hPG) between the two groups after treatment, with the D.G. being lower than the ibandronate group (I.G.). Glycosylated haemoglobin (HbA1c) was lower in the D.G. than in the I.G. after treatment, but the difference between them was insignificant. In the D.G., serum active GLP-1 levels increased after treatment, and serum DPP-4 levels decreased. Serum GLP-1 and DPP-4 levels in the I.G. did not change compared with those before treatment. In conclusion, In the clinical management of postmenopausal osteoporosis patients with combined T2DM, the choice of RANKL inhibitors as anti-osteoporosis therapy may benefit their glycaemic parameters by elevating serum active GLP-1 levels and decreasing serum DPP-4 levels.

Transepithelial Transport of the Bifunctional Peptide IPYWTY Indirectly Induced Insulin Release Mediated by Active GLP-1

There is currently no appropriate cell model suitable for evaluating the insulinotropic effects of DPP-4 inhibitory peptides (DPP-4IPs) mediated by active glucagon-like peptide-17-36 (active GLP-1). The study aims to evaluate the transepithelial transport of IPYWTY on its in situ insulinotropic effects by using a 2D and dual-layered coculture cell model that consists of Caco-2 and NCI-H716 cells on the apical (AP) side and β-TC-6 cells on the basolateral (BL) side. During transportation, IPYWTY was absorbed in its intact form through PepT1 and paracellular transport. Meanwhile, it was degraded to several peptide fragments, including PYWTY, YWTY, WTY, and IPY, which decreased its in situ DPP-4 inhibitory activity. IPYWTY does not directly stimulate insulin release in β-TC-6 cells, while it increased the active GLP-1 level from 76.57 ± 15.16 to 95.63 ± 1.99 pM (1.25 times) in NCI-H716 cells. Interestingly, IPYWTY indirectly increased insulin levels from 426.91 ± 6.07 to 573.94 ± 2.97 μIU/mL (1.34 times) in the 2D and dual-layered coculture cell model for its dual function of stimulating active GLP-1 secretion and DPP-4 inhibition. These results suggested that the 2D and dual-layered coculture cell model is an alternative strategy for effectively evaluating the insulinotropic effects of DPP-4IPs mediated by active GLP-1.

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

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

SIRT1 Controls Enteroendocrine Progenitor Cell Proliferation in High-Fat Diet-Fed Mice

BACKGROUND & AIMS

We aimed to investigate how sirtuin 1 (SIRT1), a conserved mammalian Nicotinamide adenine dinucleotide+-dependent protein deacetylase, regulates the number of enteroendocrine cells (EECs). EECs benefit metabolism, and their increase potentially could treat type 2 diabetes and obesity.

METHODS

We used mice with specific Sirt1 disruption in the intestinal epithelium (VilKO, villin-Cre+, and Sirt1flox/flox mice) or enteroendocrine progenitor cells (EEPCs) (NgnKO, neurogenin 3-Cre+, Sirt1flox/flox mice) and mice with increased SIRT1 activity owing to overexpression (Sir2d mice) or 24-hour fasting. Mice were fed a high-fat diet (HFD), and blood glucagon-like peptide 1 (GLP-1) and glucose levels were measured. Intestinal tissues, EECs, and formed organoids were analyzed using quantitative polymerase chain reaction, immunoblotting, and immunohistochemistry.

RESULTS

In HFD-fed VilKO and NgnKO mice, an increase in EECs (42.3% and 37.2%), GLP-1- or GLP-2-producing L cells (93.0% and 61.4%), and GLP-1 (85.7% and 109.6%) was observed after glucose loading, explaining the improved metabolic phenotype of HFD-VilKO mice. These increases were associated with up-regulated expression of neurogenin 3 (EEPC marker) in crypts of HFD-VilKO and HFD-NgnKO mice, respectively. Conversely, Sir2d or 24-hour fasted mice showed a decrease in EECs (21.6%), L cells (41.6%), and proliferative progenitor cells. SIRT1 overexpression- or knockdown-mediated change in the progenitor cell proliferation was associated with Wnt/β-catenin activity changes. Notably, Wnt/β-catenin inhibitor completely suppressed EEC and L-cell increases in HFD-VilKO mice or organoids from HFD-VilKO and HFD-NgnKO mice.

CONCLUSIONS

Intestinal SIRT1 in EECs modulates the EEPC cycle by regulating β-catenin activity and can control the number of EECs in HFD-fed mice, which is a previously unknown role.

Disparities in the Glycemic and Incretin Responses to Intraduodenal Glucose Infusion Between Healthy Young Men and Women

CONTEXT

Premenopausal women are at a lower risk of type 2 diabetes (T2D) compared to men, but the underlying mechanism(s) remain elusive. The secretion of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), from the small intestine is a major determinant of glucose homeostasis and may be influenced by sex.

OBJECTIVES

This study compared blood glucose and plasma insulin and incretin responses to intraduodenal glucose infusions in healthy young males and females.

DESIGN

In Study 1, 9 women and 20 men received an intraduodenal glucose infusion at 2 kcal/min for 60 minutes. In Study 2, 10 women and 26 men received an intraduodenal glucose at 3 kcal/min for 60 minutes. Venous blood was sampled every 15 minutes for measurements of blood glucose and plasma insulin, GLP-1 and GIP.

RESULTS

In response to intraduodenal glucose at 2 kcal/min, the incremental area under the curve between t = 0-60 minutes (iAUC0-60min) for blood glucose and plasma GIP did not differ between the 2 groups. However, iAUC0-60min for plasma GLP-1 (P = 0.016) and insulin (P = 0.011) were ∼2-fold higher in women than men. In response to intraduodenal glucose at 3 kcal/min, iAUC0-60min for blood glucose, plasma GIP, and insulin did not differ between women and men, but GLP-1 iAUC0-60min was 2.5-fold higher in women (P = 0.012).

CONCLUSION

Healthy young women exhibit comparable GIP but a markedly greater GLP-1 response to intraduodenal glucose than men. This disparity warrants further investigations to delineate the underlying mechanisms and may be of relevance to the reduced risk of diabetes in premenopausal women when compared to men.

The alleviating effect and mechanism of GLP-1 on ulcerative colitis

Ulcerative Colitis (UC) is a major type of chronic inflammatory bowel disease of the colonic mucosa and exhibits progressive morbidity. The incidence and prevalence of UC is increasing worldwide. The global burden of UC, which can substantially reduce quality of life, is clearly increasing. These data highlight the need for research into prevention of UC and innovations in health-care systems to manage this complex and costly disease. Glucagon-like peptide-1 (GLP-1), a new antidiabetic drug, is used to treat Type 2 Diabetes Mellitus (T2DM). Accumulating evidence suggests that GLP-1 has additional roles other than glucose-lowering effects. Despite the abundance of GLP-1 research, studies in UC have been less consistent, especially body weight; for example, body weight, colon length, colon injury score, intestinal microbiota, remain to be studied further. To date, the molecular mechanism of the protective effect of GLP-1 on UC remains obscure. The effect of GLP-1 was studied by using a dextran sulfate sodium (DSS)-induced colitic mice and lipopolysaccharide (LPS) treated RAW264.7 cells (macrophage cell line) under in vivo and in vitro conditions, respectively. Our results indicate that GLP-1 significantly relieves ulcerative colitis as it represses the production of proinflammatory mediators. In addition, GLP-1 blocks the activation of the protein kinase B (AKT)/nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) signaling pathways. GLP-1 also alleviates DSS-induced injury to the intestinal mucosa and dysbiosis of gut microbiota. Altogether, GLP-1 has protection effect on ulcerative colitis. Thus, GLP-1 can be considered as a potential therapeutic candidate for the treatment of UC.

Effects of Quinine on the Glycaemic Response to, and Gastric Emptying of, a Mixed-Nutrient Drink in Females and Males

Intraduodenal quinine, in the dose of 600 mg, stimulates glucagon-like peptide-1 (GLP-1), cholecystokinin and insulin; slows gastric emptying (GE); and lowers post-meal glucose in men. Oral sensitivity to bitter substances may be greater in women than men. We, accordingly, evaluated the dose-related effects of quinine on GE, and the glycaemic responses to, a mixed-nutrient drink in females, and compared the effects of the higher dose with those in males. A total of 13 female and 13 male healthy volunteers received quinine-hydrochloride (600 mg ('QHCl-600') or 300 mg ('QHCl-300', females only) or control ('C'), intraduodenally (10 mL bolus) 30 min before a drink (500 kcal, 74 g carbohydrates). Plasma glucose, insulin, C-peptide, GLP-1, glucose-dependent insulinotropic polypeptide (GIP) and cholecystokinin were measured at baseline, for 30 min after quinine alone, and then for 2 h post-drink. GE was measured by 13C-acetate breath-test. QHCl-600 alone stimulated insulin, C-peptide and GLP-1 secretion compared to C. Post-drink, QHCl-600 reduced plasma glucose, stimulated C-peptide and GLP-1, and increased the C-peptide/glucose ratio and oral disposition index, while cholecystokinin and GIP were less, in females and males. QHCl-600 also slowed GE compared to C in males and compared to QHCl-300 in females (p < 0.05). QHCl-300 reduced post-meal glucose concentrations and increased the C-peptide/glucose ratio, compared to C (p < 0.05). Magnitudes of glucose lowering and increase in C-peptide/glucose ratio by QHCl-600 were greater in females than males (p < 0.05). We conclude that quinine modulates glucoregulatory functions, associated with glucose lowering in healthy males and females. However, glucose lowering appears to be greater in females than males, without apparent differential effects on GI functions.

Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA

BACKGROUND

According to current consensus guidelines for type 2 diabetes management, bodyweight management is as important as attaining glycaemic targets. Retatrutide, a single peptide with agonist activity at the glucose-dependent insulinotropic polypeptide (GIP), GLP-1, and glucagon receptors, showed clinically meaningful glucose-lowering and bodyweight-lowering efficacy in a phase 1 study. We aimed to examine the efficacy and safety of retatrutide in people with type 2 diabetes across a range of doses.

METHODS

In this randomised, double-blind, double-dummy, placebo-controlled and active comparator-controlled, parallel-group, phase 2 trial, participants were recruited from 42 research and health-care centres in the USA. Adults aged 18-75 years with type 2 diabetes, glycated haemoglobin (HbA1c) of 7·0-10·5% (53·0-91·3 mmol/mol), and BMI of 25-50 kg/m2 were eligible for enrolment. Eligible participants were treated with diet and exercise alone or with a stable dose of metformin (≥1000 mg once daily) for at least 3 months before the screening visit. Participants were randomly assigned (2:2:2:1:1:1:1:2) using an interactive web-response system, with stratification for baseline HbA1c and BMI, to receive once-weekly injections of placebo, 1·5 mg dulaglutide, or retatrutide maintenance doses of 0·5 mg, 4 mg (starting dose 2 mg), 4 mg (no escalation), 8 mg (starting dose 2 mg), 8 mg (starting dose 4 mg), or 12 mg (starting dose 2 mg). Participants, study site personnel, and investigators were masked to treatment allocation until after study end. The primary endpoint was change in HbA1c from baseline to 24 weeks, and secondary endpoints included change in HbA1c and bodyweight at 36 weeks. Efficacy was analysed in all randomly assigned, except inadvertently enrolled, participants, and safety was assessed in all participants who received at least one dose of study treatment. The study is registered at ClinicalTrials.gov, NCT04867785.

FINDINGS

Between May 13, 2021, and June 13, 2022, 281 participants (mean age 56·2 years [SD 9·7], mean duration of diabetes 8·1 years [7·0], 156 [56%] female, and 235 [84%] White) were randomly assigned and included in the safety analysis (45 in the placebo group, 46 in the 1·5 mg dulaglutide group, and 47 in the retatrutide 0·5 mg group, 23 in the 4 mg escalation group, 24 in the 4 mg group, 26 in the 8 mg slow escalation group, 24 in the 8 mg fast escalation group, and 46 in the 12 mg escalation group). 275 participants were included in the efficacy analyses (one each in the retatrutide 0·5 mg group, 4 mg escalation group, and 8 mg slow escalation group, and three in the 12 mg escalation group were inadvertently enrolled). 237 (84%) participants completed the study and 222 (79%) completed study treatment. At 24 weeks, least-squares mean changes from baseline in HbA1c with retatrutide were -0·43% (SE 0·20; -4·68 mmol/mol [2·15]) for the 0·5 mg group, -1·39% (0·14; -15·24 mmol/mol [1·56]) for the 4 mg escalation group, -1·30% (0·22; -14·20 mmol/mol [2·44]) for the 4 mg group, -1·99% (0·15; -21·78 mmol/mol [1·60]) for the 8 mg slow escalation group, -1·88% (0·21; -20·52 mmol/mol [2·34]) for the 8 mg fast escalation group, and -2·02% (0·11; -22·07 mmol/mol [1·21]) for the 12 mg escalation group, versus -0·01% (0·21; -0·12 mmol/mol [2·27]) for the placebo group and -1·41% (0·12; -15·40 mmol/mol [1·29]) for the 1·5 mg dulaglutide group. HbA1c reductions with retatrutide were significantly greater (p<0·0001) than placebo in all but the 0·5 mg group and greater than 1·5 mg dulaglutide in the 8 mg slow escalation group (p=0·0019) and 12 mg escalation group (p=0·0002). Findings were consistent at 36 weeks. Bodyweight decreased dose dependently with retatrutide at 36 weeks by 3·19% (SE 0·61) for the 0·5 mg group, 7·92% (1·28) for the 4 mg escalation group, 10·37% (1·56) for the 4 mg group, 16·81% (1·59) for the 8 mg slow escalation group, 16·34% (1·65) for the 8 mg fast escalation group, and 16·94% (1·30) for the 12 mg escalation group, versus 3·00% (0·86) with placebo and 2·02% (0·72) with 1·5 mg dulaglutide. For retatrutide doses of 4 mg and greater, decreases in weight were significantly greater than with placebo (p=0·0017 for the 4 mg escalation group and p<0·0001 for others) and 1·5 mg dulaglutide (all p<0·0001). Mild-to-moderate gastrointestinal adverse events, including nausea, diarrhoea, vomiting, and constipation, were reported in 67 (35%) of 190 participants in the retatrutide groups (from six [13%] of 47 in the 0·5 mg group to 12 [50%] of 24 in the 8 mg fast escalation group), six (13%) of 45 participants in the placebo group, and 16 (35%) of 46 participants in the 1·5 mg dulaglutide group. There were no reports of severe hypoglycaemia and no deaths during the study.

INTERPRETATION

In people with type 2 diabetes, retatrutide showed clinically meaningful improvements in glycaemic control and robust reductions in bodyweight, with a safety profile consistent with GLP-1 receptor agonists and GIP and GLP-1 receptor agonists. These phase 2 data also informed dose selection for the phase 3 programme.

FUNDING

Eli Lilly and Company.

Semaglutide versus tirzepatide for people with type 2 diabetes: cost of glycemic control in Austria, the Netherlands, Lithuania, and the United Arab Emirates

OBJECTIVES

The glucagon-like peptide-1 agonist semaglutide and the dual glucose-dependent insulinotropic polypeptide tirzepatide have proven to significantly reduce glucose levels in people with type 2 diabetes. However, the costs needed to achieve a sustained decrease in HbA1c level and disease control with semaglutide and tirzepatide, respectively, are unclear. Therefore, this study aimed to compare the cost of treatment with semaglutide with the cost of treatment with tirzepatide for type 2 diabetes in Austria, the Netherlands, Lithuania, and the United Arab Emirates in order to determine their respective value for money.

METHODS

The primary outcome of this analysis was the cost in euros needed to achieve disease control in one person with type 2 diabetes based on the composite endpoint of HbA1c <7%, ≥5% weight loss, and no hypoglycemic events. In addition, analyses regarding the cost needed to reach relevant HbA1c endpoints were performed. Clinical data were obtained from the SURPASS 2 trial, registered at clinicaltrials.gov (NCT03987919), and drug cost was based on wholesale acquisition cost or pharmacy purchase prices from public domains obtained in Q1 of 2023.

RESULTS

The cost needed to achieve disease control in one person with type 2 diabetes (HbA1c <7%, ≥5% weight loss, and no hypoglycemic events) was up to three times lower using semaglutide compared with all three doses of tirzepatide in most markets. In the HbA1c analyses, semaglutide was also found to be the least expensive treatment option.

CONCLUSION

Semaglutide provides better value for money than tirzepatide for HbA1c-lowering endpoints.

Dosing Patterns of Dulaglutide and Semaglutide in Patients with Type 2 Diabetes in the United Kingdom and Germany: A Retrospective Cohort Study

INTRODUCTION

As new glucagon-like peptide 1 receptor agonist (GLP-1 RA) formulations are available, the aim of this study was to understand dulaglutide and subcutaneous (s.c.) semaglutide dosing patterns in people with type 2 diabetes mellitus (T2DM) in the UK and Germany as well as oral semaglutide in the UK.

METHODS

Adults with evidence of T2DM and a prescription of dulaglutide or semaglutide between August 2020 and December 2021 were identified using the IQVIA Longitudinal Prescription Data (LRx). Patients were divided into cohort 1 (incident users) and cohort 2 (prevalent users) based on previous exposure to GLP-1 RAs and were followed up to 12 months post-index.

RESULTS

During the patient selection window in Germany and the UK, 368,320 and 123,548 patients respectively received at least one prescription of a study GLP-1 RA. Among dulaglutide users in Germany at 12 months post-index, the 1.5-mg dosage formulation was the most common for both cohort 1 (65.6%) and 2 (71.2%). Among s.c. semaglutide users at 12 months post-index, 39.2% and 58.4% of cohort 1 received 0.5 mg and 1.0 mg, respectively. In the UK, at 12 months post-index, the most common dulaglutide dosage formulation was 1.5 mg (71.7% cohort 1 and 80.9% cohort 2). Among s.c. semaglutide users at 12 months post-index, 0.5- and 1.0-mg formulations were the most common for both cohort 1 (38.9% and 56.0%, respectively) and cohort 2 (29.5% and 67.1%, respectively). Prescribing of the more recently introduced 3.0- and 4.5-mg formulations for dulaglutide and oral semaglutide was also reported in the study.

CONCLUSION

Dosing patterns of GLP-1 RAs, although similar between the UK and Germany, were heterogeneous over time. Given that the higher dulaglutide doses and oral semaglutide were recently introduced to the market, additional real-world evidence studies which include clinical outcomes is required.

Paracrine relationship between incretin hormones and endogenous 5-hydroxytryptamine in the small and large intestine

BACKGROUND

Enterochromaffin (EC) cell-derived 5-hydroxytryptamine (5-HT) is a mediator of toxin-induced reflexes, initiating emesis via vagal and central 5-HT3 receptors. The amine is also involved in gastrointestinal (GI) reflexes that are prosecretory and promotile, and recently 5-HT's roles in chemosensation in the distal bowel have been described. We set out to establish the efficacy of 5-HT signaling, local 5-HT levels and pharmacology in discrete regions of the mouse small and large intestine. We also investigated the inter-relationships between incretin hormones, glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) and endogenous 5-HT in mucosal and motility assays.

METHODS

Adult mouse GI mucosae were mounted in Ussing chambers and area-specific studies were performed to establish the 5-HT3 and 5-HT4 pharmacology, the sidedness of responses, and the inter-relationships between incretins and endogenous 5-HT. Natural fecal pellet transit in vitro and full-length GI transit in vivo were also measured.

KEY RESULTS

We observed the greatest level of tonic and exogenous 5-HT-induced ion transport and highest levels of 5-HT in ascending colon mucosa. Here both 5-HT3 and 5-HT4 receptors were involved but elsewhere in the GI tract epithelial basolateral 5-HT4 receptors mediate 5-HT's prosecretory effect. Exendin-4 and GIP induced 5-HT release in the ascending colon, while L cell-derived PYY also contributed to GIP mucosal effects in the descending colon. Both peptides slowed colonic transit.

CONCLUSIONS & INFERENCES

We provide functional evidence for paracrine interplay between 5-HT, GLP-1 and GIP, particularly in the colonic mucosal region. Basolateral epithelial 5-HT4 receptors mediated both 5-HT and incretin mucosal responses in healthy colon.

Weight loss with subcutaneous semaglutide versus other glucagon-like peptide 1 receptor agonists in type 2 diabetes: a systematic review

Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) reduce elevated blood glucose levels and induce weight loss. Multiple GLP-1 RAs and one combined GLP-1/glucose-dependent insulinotropic polypeptide agonist are currently available. This review was conducted with the aim of summarising direct comparisons between subcutaneous semaglutide and other GLP-1 RAs in individuals with type 2 diabetes (T2D), particularly with respect to efficacy for inducing weight loss and improving other markers of metabolic health. This systematic review of PubMed and Embase from inception to early 2022 was registered on PROSPERO and was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology guidelines. Of the 740 records identified in the search, five studies fulfilled the inclusion criteria. Comparators included liraglutide, exenatide, dulaglutide and tirzepatide. In the identified studies, multiple dosing regimens were utilised for semaglutide. Randomised trials support the superior efficacy of semaglutide over other GLP-1 RAs with respect to weight loss in T2D, but tirzepatide is more effective than semaglutide.

Whey Protein Premeal Lowers Postprandial Glucose Concentrations in Adults Compared with Water-The Effect of Timing, Dose, and Metabolic Status: a Systematic Review and Meta-analysis

BACKGROUND

Serving whey protein before a meal in order to lower postprandial blood glucose concentrations is known as a premeal. The underlying mechanisms are only partly understood but may involve stimulation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin secretion together with a slower gastric emptying rate.

OBJECTIVES

The objective of this systematic review and meta-analysis was to review all randomized clinical trials investigating premeals with whey protein in comparison with a nonactive comparator (control) that evaluated plasma glucose, GLP-1, GIP, insulin, and/or gastric emptying rate. Secondary aims included subgroup analyses on the timing and dose of the premeal together with the metabolic state of the participants [lean, obese, and type 2 diabetes mellitus (T2DM)].

METHODS

We searched EMBASE, CENTRAL, PUBMED, and clinicaltrials.gov and found 16 randomized crossover trials with a total of 244 individuals. The last search was performed on 9 August, 2022.

RESULTS

Whey protein premeals lowered peak glucose concentration by -1.4 mmol/L [-1.9 mmol/L; -0.9 mmol/L], and the area under the curve for glucose was -0.9 standard deviation (SD) [-1.2 SD; -0.6 SD] compared with controls (high certainty). In association with these findings, whey protein premeals elevated GLP-1 (low certainty) and peak insulin (high certainty) concentrations and slowed gastric emptying rate (high certainty) compared with controls. Subgroup analyses showed a more pronounced and prolonged glucose-lowering effect in individuals with T2DM compared with participants without T2DM. The available evidence did not elucidate the role of GIP. The protein dose used varied between 4 and 55 g, and meta-regression analysis showed that the protein dose correlated with the glucose-lowering effects.

CONCLUSIONS

In conclusion, whey protein premeals lower postprandial blood glucose, reduce gastric emptying rate, and increase peak insulin. In addition, whey protein premeals may elevate plasma concentrations of GLP-1. Whey protein premeals may possess clinical potential, but the long-term effects await future clinical trials.

Effects of GLP-1 receptor agonists on neurological complications of diabetes

Emerging evidence suggests that treatment with glucagon-like peptide-1 receptor agonists (GLP-1 RAs) could be an interesting treatment strategy to reduce neurological complications such as stroke, cognitive impairment, and peripheral neuropathy. We performed a systematic review to examine the evidence concerning the effects of GLP-1 RAs on neurological complications of diabetes. The databases used were Pubmed, Scopus and Cochrane. We selected clinical trials which analysed the effect of GLP-1 RAs on stroke, cognitive impairment, and peripheral neuropathy. We found a total of 19 studies: 8 studies include stroke or major cardiovascular events, 7 involve cognitive impairment and 4 include peripheral neuropathy. Semaglutide subcutaneous and dulaglutide reduced stroke cases. Liraglutide, albiglutide, oral semaglutide and efpeglenatide, were not shown to reduce the number of strokes but did reduce major cardiovascular events. Exenatide, dulaglutide and liraglutide improved general cognition but no significant effect on diabetic peripheral neuropathy has been reported with GLP-1 RAs. GLP-1 RAs are promising drugs that seem to be useful in the reduction of some neurological complications of diabetes. However, more studies are needed.

Liraglutide restores impaired associative learning in individuals with obesity

Survival under selective pressure is driven by the ability of our brain to use sensory information to our advantage to control physiological needs. To that end, neural circuits receive and integrate external environmental cues and internal metabolic signals to form learned sensory associations, consequently motivating and adapting our behaviour. The dopaminergic midbrain plays a crucial role in learning adaptive behaviour and is particularly sensitive to peripheral metabolic signals, including intestinal peptides, such as glucagon-like peptide 1 (GLP-1). In a single-blinded, randomized, controlled, crossover basic human functional magnetic resonance imaging study relying on a computational model of the adaptive learning process underlying behavioural responses, we show that adaptive learning is reduced when metabolic sensing is impaired in obesity, as indexed by reduced insulin sensitivity (participants: N = 30 with normal insulin sensitivity; N = 24 with impaired insulin sensitivity). Treatment with the GLP-1 receptor agonist liraglutide normalizes impaired learning of sensory associations in men and women with obesity. Collectively, our findings reveal that GLP-1 receptor activation modulates associative learning in people with obesity via its central effects within the mesoaccumbens pathway. These findings provide evidence for how metabolic signals can act as neuromodulators to adapt our behaviour to our body's internal state and how GLP-1 receptor agonists work in clinics.

Treatment with GLP-1 receptor agonists is associated with significant weight loss and favorable headache outcomes in idiopathic intracranial hypertension

BACKGROUND

In idiopathic intracranial hypertension (IIH), sustained weight loss is the main pillar in modifying disease course, whereby glucagon-like peptide-1 receptor agonists (GLP-1-RAs) could present an attractive treatment option.

METHODS

In this open-label, single-center, case-control pilot study, patients with IIH (pwIIH) and a body mass index (BMI) of ≥ 30 kg/m² were offered to receive a GLP-1-RA (semaglutide, liraglutide) in addition to the usual care weight management (UCWM). Patients electing for UCWM only served as a control group matched for age-, sex- and BMI (1:2 ratio). The primary endpoint was the percentage weight loss at six months (M6) compared to baseline. Secondary endpoints included the rate of patients with a weight loss of ≥ 10%, monthly headache days (MHD), the rate of patients with a ≥ 30% and ≥ 50% reduction in MHD, visual outcome parameters, and adverse events (AEs).

RESULTS

We included 39 pwIIH (mean age 33.6 years [SD 8.0], 92.3% female, median BMI 36.3 kg/m² [IQR 31.4-38.3]), with 13 patients being treated with GLP-1-RAs. At M6, mean weight loss was significantly higher in the GLP-1-RA group (-12.0% [3.3] vs. -2.8% [4.7]; p < 0.001). Accordingly, weight loss of ≥ 10% was more common in this group (69.2% vs. 4.0%; p < 0.001). Median reduction in MHD was significantly higher in the GLP-1-RA group (-4 [-10.5, 0.5] vs. 0 [-3, 1]; p = 0.02), and the 50% responder rate was 76.9% vs. 40.0% (p = 0.04). Visual outcome parameters did not change significantly from baseline to M6. Median reduction in acetazolamide dosage was significantly higher in the GLP-1-RA group (-16.5% [-50, 0] vs. 0% [-25, 50]; p = 0.04). AEs were mild or moderate and attributed to gastrointestinal symptoms in 9/13 patients. None of the AEs led to premature treatment discontinuation.

CONCLUSIONS

This open-label, single-center pilot study suggests that GLP-1-RAs are an effective and safe treatment option for achieving significant weight loss with a favorable effect on headache, leading to reduced acetazolamide dosage in pwIIH.

Interventions for people with type 2 diabetes mellitus fasting during Ramadan

BACKGROUND

Fasting during Ramadan is obligatory for adult Muslims, except those who have a medical illness. Many Muslims with type 2 diabetes (T2DM) choose to fast, which may increase their risks of hypoglycaemia and dehydration.

OBJECTIVES

To assess the effects of interventions for people with type 2 diabetes fasting during Ramadan.

SEARCH METHODS

We searched CENTRAL, MEDLINE, PsycINFO, CINAHL, WHO ICTRP and ClinicalTrials.gov (29 June 2022) without language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) conducted during Ramadan that evaluated all pharmacological or behavioural interventions in Muslims with T2DM.

DATA COLLECTION AND ANALYSIS

Two authors screened and selected records, assessed risk of bias and extracted data independently. Discrepancies were resolved by a third author. For meta-analyses we used a random-effects model, with risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes with their associated 95% confidence intervals (CIs). We assessed the certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 17 RCTs with 5359 participants, with a four-week study duration and at least four weeks of follow-up. All studies had at least one high-risk domain in the risk of bias assessment. Four trials compared dipeptidyl-peptidase-4 (DPP-4) inhibitors with sulphonylurea. DPP-4 inhibitors may reduce hypoglycaemia compared to sulphonylureas (85/1237 versus 165/1258, RR 0.53, 95% CI 0.41 to 0.68; low-certainty evidence). Serious hypoglycaemia was similar between groups (no events were reported in two trials; 6/279 in the DPP-4 versus 4/278 in the sulphonylurea group was reported in one trial, RR 1.49, 95% CI 0.43 to 5.24; very low-certainty evidence). The evidence was very uncertain about the effects of DPP-4 inhibitors on adverse events other than hypoglycaemia (141/1207 versus 157/1219, RR 0.90, 95% CI 0.52 to 1.54) and HbA1c changes (MD -0.11%, 95% CI -0.57 to 0.36) (very low-certainty evidence for both outcomes). No deaths were reported (moderate-certainty evidence). Health-related quality of life (HRQoL) and treatment satisfaction were not evaluated. Two trials compared meglitinides with sulphonylurea. The evidence is very uncertain about the effect on hypoglycaemia (14/133 versus 21/140, RR 0.72, 95% CI 0.40 to 1.28) and HbA1c changes (MD 0.38%, 95% CI 0.35% to 0.41%) (very low-certainty evidence for both outcomes). Death, serious hypoglycaemic events, adverse events, treatment satisfaction and HRQoL were not evaluated. One trial compared sodium-glucose co-transporter-2 (SGLT-2) inhibitors with sulphonylurea. SGLT-2 may reduce hypoglycaemia compared to sulphonylurea (4/58 versus 13/52, RR 0.28, 95% CI 0.10 to 0.79; low-certainty evidence). The evidence was very uncertain for serious hypoglycaemia (one event reported in both groups, RR 0.90, 95% CI 0.06 to 13.97) and adverse events other than hypoglycaemia (20/58 versus 18/52, RR 1.00, 95% CI 0.60 to 1.67) (very low-certainty evidence for both outcomes). SGLT-2 inhibitors result in little or no difference in HbA1c (MD 0.27%, 95% CI -0.04 to 0.58; 1 trial, 110 participants; low-certainty evidence). Death, treatment satisfaction and HRQoL were not evaluated. Three trials compared glucagon-like peptide 1 (GLP-1) analogues with sulphonylurea. GLP-1 analogues may reduce hypoglycaemia compared to sulphonylurea (20/291 versus 48/305, RR 0.45, 95% CI 0.28 to 0.74; low-certainty evidence). The evidence was very uncertain for serious hypoglycaemia (0/91 versus 1/91, RR 0.33, 95% CI 0.01 to 7.99; very low-certainty evidence). The evidence suggests that GLP-1 analogues result in little to no difference in adverse events other than hypoglycaemia (78/244 versus 55/255, RR 1.50, 95% CI 0.86 to 2.61; very low-certainty evidence), treatment satisfaction (MD -0.18, 95% CI -3.18 to 2.82; very low-certainty evidence) or change in HbA1c (MD -0.04%, 95% CI -0.45% to 0.36%; 2 trials, 246 participants; low-certainty evidence). Death and HRQoL were not evaluated. Two trials compared insulin analogues with biphasic insulin. The evidence was very uncertain about the effects of insulin analogues on hypoglycaemia (47/256 versus 81/244, RR 0.43, 95% CI 0.13 to 1.40) and serious hypoglycaemia (4/131 versus 3/132, RR 1.34, 95% CI 0.31 to 5.89) (very low-certainty evidence for both outcomes). The evidence was very uncertain for the effect of insulin analogues on adverse effects other than hypoglycaemia (109/256 versus 114/244, RR 0.83, 95% CI 0.44 to 1.56; very low-certainty evidence), all-cause mortality (1/131 versus 0/132, RR 3.02, 95% CI 0.12 to 73.53; very low-certainty evidence) and HbA1c changes (MD 0.03%, 95% CI -0.17% to 0.23%; 1 trial, 245 participants; very low-certainty evidence). Treatment satisfaction and HRQoL were not evaluated. Two trials compared telemedicine with usual care. The evidence was very uncertain about the effect of telemedicine on hypoglycaemia compared with usual care (9/63 versus 23/58, RR 0.42, 95% CI 0.24 to 0.74; very low-certainty evidence), HRQoL (MD 0.06, 95% CI -0.03 to 0.15; very low-certainty evidence) and HbA1c change (MD -0.84%, 95% CI -1.51% to -0.17%; very low-certainty evidence). Death, serious hypoglycaemia, AEs other than hypoglycaemia and treatment satisfaction were not evaluated. Two trials compared Ramadan-focused patient education with usual care. The evidence was very uncertain about the effect of Ramadan-focused patient education on hypoglycaemia (49/213 versus 42/209, RR 1.17, 95% CI 0.82 to 1.66; very low-certainty evidence) and HbA1c change (MD -0.40%, 95% CI -0.73% to -0.06%; very low-certainty evidence). Death, serious hypoglycaemia, adverse events other than hypoglycaemia, treatment satisfaction and HRQoL were not evaluated. One trial compared drug dosage reduction with usual care. The evidence is very uncertain about the effect of drug dosage reduction on hypoglycaemia (19/452 versus 52/226, RR 0.18, 95% CI 0.11 to 0.30; very low-certainty evidence). No participants experienced adverse events other than hypoglycaemia during the study (very low-certainty evidence). Death, serious hypoglycaemia, treatment satisfaction, HbA1c change and HRQoL were not evaluated.

AUTHORS' CONCLUSIONS

There is no clear evidence of the benefits or harms of interventions for individuals with T2DM who fast during Ramadan. All results should be interpreted with caution due to concerns about risk of bias, imprecision and inconsistency between studies, which give rise to low- to very low-certainty evidence. Major outcomes, such as mortality, health-related quality of life and severe hypoglycaemia, were rarely evaluated. Sufficiently powered studies that examine the effects of various interventions on these outcomes are needed.

Glucagon-like peptide 1(GLP-1) receptor agonists in the management of the patient with type 2diabetes mellitus and chronic kidney disease: an approach for the nephrologist

Diabetic kidney disease, a common complication in patients with type 2 diabetes mellitus, is associated with a markedly increased morbidity and mortality, especially of cardiovascular origin, and faster progression to end-stage renal disease. To date, reducing cardiovascular and renal risk in this population was based on strict control of cardiovascular risk factors and the renin-angiotensin system blockade. More recently, sodium-glucose cotransporter type 2 inhibitors have demonstrated to offer cardiovascular and renal protection, but the residual risk remains high and their antihyperglycemic efficacy is limited in moderate-severe CKD. Therefore, drugs with a potent antihyperglycemic effect, independent of the glomerular filtration rate, with a low risk of hypoglycemia, that reduce weight in overweight/obese patients and that provide cardiovascular and renal protection, such as GLP-1 receptor agonists, are needed. However, these drugs require subcutaneous administration, which may limit their early use. The recent availability of oral semaglutide may facilitate the early introduction of this family with proven cardiovascular and renal benefits and excellent safety profile. In this review the family is analyzed as well as their cardiovascular and renal effects.

The new evidence on cardiorenal benefits of sodium-glucose cotransporter 2 inhibitors in type 1 diabetes: one step closer to their use in this setting?

Chronic kidney disease (CKD) affects 30-40% of persons with type 1 diabetes mellitus (T1DM), markedly increasing the risk of kidney failure and cardiovascular events. The excessive mortality observed in T1DM compared to the general population can be attributed to the presence of CKD, with cardiovascular disease as the leading cause of premature death. A recently published, robust real-world study investigated the impact of sodium-glucose cotransporter 2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1 RA) adjunctive therapy on blood glucose levels, adverse events, and cardio-renal outcomes among individuals with T1DM. GLP-1 RA provided greater reduction in glycated hemoglobin in comparison to SGLT2i therapy, whereas the latter reduced the risk of CKD, heart failure, and hospitalization for any cause. However, the SGLT2i treated cohort had a higher risk of diabetic ketoacidosis (DKA). The study provides promising evidence that the protective cardiorenal effects of SGLT2i, previously confirmed in people with and without type 2 diabetes mellitus, might also be present in T1DM. However, the benefits and risks, especially the risk of DKA, should be further examined in dedicated large-scale randomized controlled trials.

An updated patent review of GLP-1 receptor agonists (2020-present)

INTRODUCTION

Type 2 diabetes (T2DM) and obesity present significant global health issues, requiring the development of long-lasting and highly effective pharmacotherapies. Although glucagon-like peptide-1 receptor agonists (GLP-1RAs) are commonly used for diabetes treatment, their potential for addressing obesity is still being explored.

AREAS COVERED

This review offers a comprehensive overview of recently published patents from January 2020 to July 2023, focusing on modified GLP-1RAs, small molecule GLP-1RAs, GLP-1 R-based multi-agonists, GLP-1RA-based fusion proteins, and combination therapies. The patents discussed pertain to the treatment and prevention of diabetes and obesity. Patent searches were conducted using the PATENTSCOPE database of the World Intellectual Property Organization, using the keywords GLP-1, GLP-1/GIP, GLP-1/GCG, and GLP-1/GCG/GIP.

EXPERT OPINION

In recent years, patents have emphasized two main goals for developing GLP-1RAs drugs: oral delivery and improved weight reduction effects. To address the growing demand for improved treatments, researchers have focused their efforts on developing GLP-1 R-based multi-agonists, orally administered GLP-1RAs, and combination therapies utilizing GLP-1RAs. These new approaches offer promising benefits, such as improved effectiveness by targeting multiple pathways and reduced side effects. Additionally, the development of new uses, oral forms, and long-lasting preparations will be crucial in shaping the future market potential of GLP-1 drugs.

Retatrutide showing promise in obesity (and type 2 diabetes)

INTRODUCTION

Obesity is a major risk factor for cardiovascular disease, diabetes, osteoarthritis, and some cancers. Retatrutide stimulates Glucagon-like peptide 1 (GLP-1), Glucose-dependent insulinotropic polypeptide (GIP) receptors, and glucagon receptors, and is being developed for the treatment of obesity and type 2 diabetes.

AREAS COVERED

A phase 2 clinical trial of retatrutide (LY3437943) in the treatment of obesity. The primary end point was percentage change in weight from baseline to 24 weeks, which ranged from -7.2% to -~18% as the dose of retatrutide increased from 1 mg to 12 mg. The most frequent adverse events were gastrointestinal (nausea, diarrhea, vomiting).

EXPERT OPINION

The results for retatrutide in phase 2 for obesity (and diabetes) are mostly encouraging. Consistent with being a GLP-1 receptor agonist, heart rate was increased by up to 6.7 beats/min by retatrutide, which may be detrimental and offset some of the benefits of weight loss. Presumably, retatrutide is being developed as a challenger to the recently developed weight loss medicines; semaglutide and/or tirzepatide. Thus, comparator studies are needed between retatrutide and these drugs, but none are ongoing and, in my opinion, this lack is a major omission in the development of retatrutide.

Effect of gastric distension with concurrent small intestinal saline or glucose infusion on incretin hormone secretion in healthy individuals: A randomized, controlled, crossover study

AIM

To evaluate the effect of gastric distension, induced using a gastric 'barostat', on the secretion of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) in the presence and absence of small intestinal nutrients in healthy individuals.

MATERIALS AND METHODS

Eight healthy participants (two females, six males, mean age 69.3 ± 1.2 years, body mass index 23.5 ± 0.8 kg/m2 ) were each studied on four occasions when they received an intraduodenal infusion of either (i) 0.9% saline or (ii) glucose delivered at a rate of 3 kcal/min both with, and without, an intragastric balloon with the pressure set to 8 mmHg above the intragastric minimum distending pressure.

RESULTS

Following intraduodenal saline or glucose infusion, there was no difference in plasma GLP-1 with or without gastric distension (P = 1.00 for both saline and glucose infusions). There was also no difference in plasma GIP with or without gastric distension (P = 1.00 for saline infusion and P = .99 for glucose infusion).

CONCLUSIONS

Gastric distension, either alone or during small intestinal glucose exposure, does not stimulate incretin hormone secretion significantly in healthy humans.

The glucagon-like peptide-1 (GLP-1) analogue semaglutide reduces alcohol drinking and modulates central GABA neurotransmission

Growing evidence indicates that the glucagon-like peptide-1 (GLP-1) system is involved in the neurobiology of addictive behaviors, and GLP-1 analogues may be used for the treatment of alcohol use disorder (AUD). Here, we examined the effects of semaglutide, a long-acting GLP-1 analogue, on biobehavioral correlates of alcohol use in rodents. A drinking-in-the-dark procedure was used to test the effects of semaglutide on binge-like drinking in male and female mice. We also tested the effects of semaglutide on binge-like and dependence-induced alcohol drinking in male and female rats, as well as acute effects of semaglutide on spontaneous inhibitory postsynaptic currents (sIPSCs) from central amygdala (CeA) and infralimbic cortex (ILC) neurons. Semaglutide dose-dependently reduced binge-like alcohol drinking in mice; a similar effect was observed on the intake of other caloric/noncaloric solutions. Semaglutide also reduced binge-like and dependence-induced alcohol drinking in rats. Semaglutide increased sIPSC frequency in CeA and ILC neurons from alcohol-naive rats, suggesting enhanced GABA release, but had no overall effect on GABA transmission in alcohol-dependent rats. In conclusion, the GLP-1 analogue semaglutide decreased alcohol intake across different drinking models and species and modulated central GABA neurotransmission, providing support for clinical testing of semaglutide as a potentially novel pharmacotherapy for AUD.

A peptide triple agonist of GLP-1, neuropeptide Y1, and neuropeptide Y2 receptors promotes glycemic control and weight loss

Mechanisms underlying long-term sustained weight loss and glycemic normalization after obesity surgery include changes in gut hormone levels, including glucagon-like peptide 1 (GLP-1) and peptide YY (PYY). We demonstrate that two peptide biased agonists (GEP44 and GEP12) of the GLP-1, neuropeptide Y1, and neuropeptide Y2 receptors (GLP-1R, Y1-R, and Y2-R, respectively) elicit Y1-R antagonist-controlled, GLP-1R-dependent stimulation of insulin secretion in both rat and human pancreatic islets, thus revealing the counteracting effects of Y1-R and GLP-1R agonism. These agonists also promote insulin-independent Y1-R-mediated glucose uptake in muscle tissue ex vivo and more profound reductions in food intake and body weight than liraglutide when administered to diet-induced obese rats. Our findings support a role for Y1-R signaling in glucoregulation and highlight the therapeutic potential of simultaneous receptor targeting to achieve long-term benefits for millions of patients.

Chronic Kidney Disease and Obesity

There is a pandemic of obesity worldwide and in Europe up to 30% of the adult population is already obese. Obesity is strongly related to the risk of CKD, progression of CKD, and end-stage renal disease (ESRD), also after adjustment for age, sex, race, smoking status, comorbidities, and laboratory tests. In the general population, obesity increases the risk of death. In nondialysis-dependent CKD patients, the association between body mass index and weight with mortality is controversial. In ESRD patients, obesity is paradoxically associated with better survival. There are only a few studies investigating changes in weight in these patients and in most weight loss was associated with higher mortality. However, it is not clear if weight change was intentional or unintentional and this is an important limitation of these studies. Management of obesity includes life-style interventions, bariatric surgery, and pharmacotherapy. In the last 2 years, a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist and GLP-1 and glucose-dependent insulinotropic polypeptide receptor agonist were shown to be effective in managing weight loss in non-CKD patients, but we are awaiting results of more definitive studies in CKD patients.

Evaluation of Out-of-Pocket Costs and Treatment Intensification With an SGLT2 Inhibitor or GLP-1 RA in Patients With Type 2 Diabetes and Cardiovascular Disease

Importance

The latest guidelines continue to recommend sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) for patients with type 2 diabetes (T2D) and established cardiovascular disease (CVD). Despite this, overall use of these 2 drug classes has been suboptimal.

Objective

To assess the association of high out-of-pocket (OOP) costs and the initiation of an SGLT2 inhibitor or GLP-1 RA among adults with T2D and established CVD who are treated with metformin-treated.

Design, Setting, and Participants

This retrospective cohort study used 2017 to 2021 data from the Optum deidentified Clinformatics Data Mart Database. Each individual in the cohort was categorized into quartiles of OOP costs for a 1-month supply of SGLT2 inhibitor and GLP-1 RA based on their health plan assignment. Data were analyzed from April 2021 to October 2022.

Exposures

OOP cost for SGLT2 inhibitors and GLP-1 RA.

Main Outcomes and Measures

The primary outcome was treatment intensification, defined as a new dispensing (ie, initiation) of either an SGLT2 inhibitor or GLP-1 RA, among patients with T2D previously treated with metformin monotherapy. For each drug class separately, Cox proportional hazards models were used to adjust for demographic, clinical, plan, clinician, and laboratory characteristics to estimate the hazard ratios of treatment intensification comparing the highest vs the lowest quartile of OOP costs.

Results

Our cohort included 80 807 adult patients (mean [SD] age, 72 [9.5] years, 45 129 [55.8%] male; 71 128 [88%] were insured with Medicare Advantage) with T2D and established CVD on metformin monotherapy. Patients were followed for a median (IQR) of 1080 days (528 to 1337). The mean (SD) of OOP costs in the highest vs lowest quartile was $118 [32] vs $25 [12] for GLP-1 RA, and $91 [25] vs $23 [9] for SGLT2 inhibitors. Compared with patients in plans with the lowest quartile (Q1) of OOP costs, patients in plans with the highest quartile (Q4) of costs were less likely to initiate a GLP-1 RA (adjusted HR, 0.87 [95% CI, 0.78 to 0.97]) or an SGLT2 inhibitor (adjusted HR, 0.80 [95% CI, 0.73 to 0.88]). The median (IQR) number of days to initiating a GLP-1 RA was 481 (207-820) days in Q1 and 556 (237-917) days in Q4 of OOP costs and 520 (193-876) days in Q1 vs 685 (309-1017) days in Q4 for SGLT2 inhibitors.

Conclusions and Relevance

In this cohort study of more than 80 000 older adults with T2D and established CVD covered by Medicare Advantage and commercial plans, those in the highest quartile of OOP cost were 13% and 20% less likely to initiate a GLP-1 RA or SGLT2 inhibitor, respectively, when compared with those in the lowest quartile of OOP costs.

Semaglutide 2·4 mg once weekly in patients with non-alcoholic steatohepatitis-related cirrhosis: a randomised, placebo-controlled phase 2 trial

BACKGROUND

Patients with non-alcoholic steatohepatitis (NASH)-related cirrhosis are at high risk of liver-related and all-cause morbidity and mortality. We investigated the efficacy and safety of the glucagon-like peptide-1 analogue semaglutide in patients with NASH and compensated cirrhosis.

METHODS

This double-blind, placebo-controlled phase 2 trial enrolled patients from 38 centres in Europe and the USA. Adults with biopsy-confirmed NASH-related cirrhosis and body-mass index (BMI) of 27 kg/m2 or more were randomly assigned (2:1) to receive either once-weekly subcutaneous semaglutide 2·4 mg or visually matching placebo. Patients were randomly allocated via an interactive web response system, stratified by presence or absence of type 2 diabetes. Patients, investigators, and those assessing outcomes were masked to treatment assignment. The primary endpoint was the proportion of patients with an improvement in liver fibrosis of one stage or more without worsening of NASH after 48 weeks, assessed by biopsy in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of study drug. The trial is closed and completed, and registered with ClinicalTrials.gov, number NCT03987451.

FINDINGS

71 patients were enrolled between June 18, 2019, and April 22, 2021; 49 (69%) patients were female and 22 (31%) were male. Patients had a mean age of 59·5 years (SD 8·0) and mean BMI of 34·9 kg/m2 (SD 5·9); 53 (75%) patients had diabetes. 47 patients were randomly assigned to the semaglutide group and 24 to the placebo group. After 48 weeks, there was no statistically significant difference between the two groups in the proportion of patients with an improvement in liver fibrosis of one stage or more without worsening of NASH (five [11%] of 47 patients in the semaglutide group vs seven [29%] of 24 in the placebo group; odds ratio 0·28 [95% CI 0·06-1·24; p=0·087). There was also no significant difference between groups in the proportion of patients who achieved NASH resolution (p=0·29). Similar proportions of patients in each group reported adverse events (42 [89%] patients in the semaglutide group vs 19 [79%] in the placebo group) and serious adverse events (six [13%] vs two [8%]). The most common adverse events were nausea (21 [45%] vs four [17%]), diarrhoea (nine [19%] vs two [8%]), and vomiting (eight [17%] vs none). Hepatic and renal function remained stable. There were no decompensating events or deaths.

INTERPRETATION

In patients with NASH and compensated cirrhosis, semaglutide did not significantly improve fibrosis or achievement of NASH resolution versus placebo. No new safety concerns were raised.

FUNDING

Novo Nordisk A/S.

Direct Assessment of Oligomerization of Chemically Modified Peptides and Proteins in Formulations using DLS and DOSY-NMR

PURPOSE

Protein higher order structure (HOS) including the oligomer distribution can be critical for efficacy, safety and stability of drug products (DP). Oligomerization is particularly relevant to chemically modified protein therapeutics that have an extended pharmacokinetics profile. Therefore, the direct assessment of protein oligomerization in drug formulation is desired for quality assurance and control.

METHODS

Here, two non-invasive methods, dynamic light scattering (DLS) and diffusion ordered spectroscopy (DOSY) NMR, were applied to measure translational diffusion coefficients (Ddls and Dnmr) of proteins in formulated drug products. The hydrodynamic molecular weights (MWhd), similar to hydrodynamic size, of protein therapeutics were derived based on a log(Ddls) vs log(MWhd) correlation model established using protein standards.

RESULTS

An exponent value of -0.40 ± 0.01 was established for DLS measured log(D) vs. log(MWhd) using protein standards and a theoretical exponent value of -0.6 was used for unstructured polyethylene glycol (PEG) chains. The analysis of DLS derived MWhd of the primary species showed the fatty acid linked glucagon-like peptide 1 (GLP-1) was in different oligomer states, but the fatty acid linked insulin and PEG linked proteins were in monomer states. Nevertheless, equilibrium and exchange between oligomers in formulations were universal and clearly evidenced from DOSY-NMR for all drugs except peginterferon alfa-2a.

CONCLUSION

The correlation models of log(D) vs. log(MWhd) could be a quick and efficient way to predict MWhd of protein, which directly informs on the state of protein folding and oligomerization in formulation.

Acarbose diminishes postprandial suppression of bone resorption in patients with type 2 diabetes

AIMS

The alpha-glucosidase inhibitor acarbose is an antidiabetic drug delaying assimilation of carbohydrates and, thus, increasing the amount of carbohydrates in the distal parts of the intestines, which in turn increases circulating levels of the gut-derived incretin hormone glucagon-like peptide 1 (GLP-1). As GLP-1 may suppress bone resorption, acarbose has been proposed to potentiate meal-induced suppression of bone resorption. We investigated the effect of acarbose treatment on postprandial bone resorption in patients with type 2 diabetes and used the GLP-1 receptor antagonist exendin(9-39)NH₂ to disclose contributory effect of acarbose-induced GLP-1 secretion.

METHODS

In a randomised, placebo-controlled, double-blind, crossover study, 15 participants with metformin-treated type 2 diabetes (2 women/13 men, age 71 (57-85 years), BMI 29.7 (23.6-34.6 kg/m²), HbA1c 48 (40-74 mmol/mol)/6.5 (5.8-11.6 %) (median and range)) were subjected to two 14-day treatment periods with acarbose and placebo, respectively, separated by a six-week wash-out period. At the end of each period, circulating bone formation and resorption markers were assessed during two randomised 4-h liquid mixed meal tests (MMT) with infusions of exendin(9-39)NH₂ and saline, respectively. Glucagon-like peptide 2 (GLP-2) was also assessed.

RESULTS

Compared to placebo, acarbose impaired the MMT-induced suppression of CTX as assessed by baseline-subtracted area under curve (P = 0.0037) and nadir of CTX (P = 0.0128). During acarbose treatment, exendin(9-39)NH₂ infusion lowered nadir of CTX compared to saline (P = 0.0344). Neither parathyroid hormone or the bone formation marker procollagen 1 intact N-terminal propeptide were affected by acarbose or GLP-1 receptor antagonism. Acarbose treatment induced a greater postprandial GLP-2 response than placebo treatment (P = 0.0479) and exendin(9-39)NH₂ infusion exacerbated this (P = 0.0002).

CONCLUSIONS

In patients with type 2 diabetes, treatment with acarbose reduced postprandial suppression of bone resorption. Acarbose-induced GLP-1 secretion may contribute to this phenomenon as the impairment was partially reversed by GLP-1 receptor antagonism. Also, acarbose-induced reductions in other factors reducing bone resorption, e.g. glucose-dependent insulinotropic polypeptide, may contribute.

Inhibition of notch signalling and mesangial expansion by combined glucagon like peptide-1 agonist and crocin therapy in animal model of diabetic nephropathy

Diabetic nephropathy (DN) is one of the devastating complications in diabetes mellitus (DM). Glucagon-like peptide-1 (GLP-1) is one of the incretins secreted from L cells in the intestine. Crocin (a carotenoid component of saffron) has antioxidants properties. We investigated the renal effects of Exendin-4 as a GLP-1 agonist and Crocin in DN.Thirty male rats were divided into five groups: control, type II DM, type II DM + Exendin-4, type II DM + Crocin ‏ and type II DM + Exendine-4 + Crocin. At the end of the experimental period, systolic and diastolic blood pressures were measured, and GFR was calculated. Blood and urine samples were collected for biochemical analysis. Tissue samples were collected from the kidney for histological examination and biochemical measurements of protein expression.Treatment with GLP-1 agonist or Crocin caused a significant improvement in renal function. Better results were achieved with simultaneous administration of both drugs with inhibition of notch signalling pathway and the related proteins.

Optimization of Physicochemical Properties of Pyrrolidine GPR40 AgoPAMs Results in a Differentiated Profile with Improved Pharmacokinetics and Reduced Off-Target Activities

GPR40 AgoPAMs are highly effective antidiabetic agents that have a dual mechanism of action, stimulating both glucose-dependent insulin and GLP-1 secretion. The early lipophilic, aromatic pyrrolidine and dihydropyrazole GPR40 AgoPAMs from our laboratory were highly efficacious in lowering plasma glucose levels in rodents but possessed off-target activities and triggered rebound hyperglycemia in rats at high doses. A focus on increasing molecular complexity through saturation and chirality in combination with reducing polarity for the pyrrolidine AgoPAM chemotype resulted in the discovery of compound 46, which shows significantly reduced off-target activities as well as improved aqueous solubility, rapid absorption, and linear PK. In vivo, compound 46 significantly lowers plasma glucose levels in rats during an oral glucose challenge yet does not demonstrate the reactive hyperglycemia effect at high doses that was observed with earlier GPR40 AgoPAMs.

Dipeptidyl Peptidase-4 Inhibitors, Glucagon-like Peptide-1 Receptor Agonists, and Sodium-Glucose Cotransporter-2 Inhibitors and COVID-19 Outcomes

PURPOSE

It has been reported that dipeptidyl peptidase-4 inhibitors (DPP-4i), glucagon-like peptide-1 receptor agonists (GLP-1 RA), and sodium-glucose cotransporter-2 inhibitors (SGLT-2i) have a role in modulation of inflammation associated with coronavirus disease 2019 (COVID-19). This study assessed the effect of these drug classes on COVID-19-related outcomes.

METHODS

Using a COVID-19 linkable administrative database, we selected patients aged ≥40 years with at least 2 prescriptions of DPP-4i, GLP-1 RA, or SGLT-2i or any other antihyperglycemic drug and a diagnosis of COVID-19 from February 15, 2020, to March 15, 2021. Adjusted odds ratios (ORs) with 95% CIs were used to calculate the association between treatments and all-cause and in-hospital mortality and COVID-19-related hospitalization. A sensitivity analysis was performed by using inverse probability treatment weighting.

FINDINGS

Overall, 32,853 subjects were included in the analysis. Multivariable models showed a reduction of the risk for COVID-19 outcomes for users of DPP-4i, GLP-1 RA, and SGLT-2i compared with nonusers, although statistical significance was reached only in DPP-4i users for total mortality (OR, 0.89; 95% CI, 0.82-0.97). The sensitivity analysis confirmed the main results reaching a significant reduction for hospital admission in GLP-1 RA users and in-hospital mortality in SGLT-2i users compared with nonusers.

IMPLICATIONS

This study found a beneficial effect in the risk reduction of COVID-19 total mortality in DPP-4i users compared with nonusers. A positive trend was also observed in users of GLP-1 RA and SGLT-2i compared with nonusers. Randomized clinical trials are needed to confirm the effect of these drug classes as potential therapy for the treatment of COVID-19.

Circulating glucagon-like peptide-1 level in patients with liver cirrhosis

BACKGROUND

Glucagon-like peptide-1 (GLP-1), a gut-derived incretin hormone, plays a pivotal role in glucose-induced insulin secretion. Currently, the role of incretin hormones in the pathogenesis of cirrhosis is not clearly defined. This study aimed to investigate circulating levels of GLP-1 in liver cirrhosis and its association with the severity of liver disease.

METHODS

A total of 80 participants including 39 patients with a definite diagnosis of liver cirrhosis and 41 healthy controls recruited in this cross-sectional study. Circulating levels of GLP-1 were determined using the ELISA method. The severity of liver cirrhosis was assessed according to the Child-Pugh, MELD (i), MELD-Na, MELD New, and UK end-stage liver disease score (UKELD) criteria.

RESULTS

The mean age of patients and healthy subjects was 42.51 ± 12.80 and 42.07 ± 10.92 years, respectively (p value = .869). The mean MELD (i), MELD-Na, MELD New, UKELD, and Child-Pugh scores were 14.36 ± 4.26, 15.26 ± 4.81, 14.74 ± 4.66, 52.33 ± 3.82, and 7.28 ± 1.50, respectively. In this study, circulating levels of GLP-1 were statistically lower in cirrhotic patients compared with healthy controls (95.26 ± 17.15 vs 111.84 ± 38.14 pg/mL; p value = .017).

CONCLUSION

Larger prospective studies are needed to explore the incretin effect in cirrhosis patients compared with healthy individuals.

The Effect of Glucagon-Like Peptide 1 Receptor Blockade on Glucagon-Induced Stimulation of Insulin Secretion

Data from transgenic rodent models suggest that glucagon acts as an insulin secretagogue by signaling through the glucagon-like peptide 1 receptor (GLP-1R) present on β-cells. However, its net contribution to physiologic insulin secretion in humans is unknown. To address this question, we studied individuals without diabetes in two separate experiments. Each subject was studied on two occasions in random order. In the first experiment, during a hyperglycemic clamp, glucagon was infused at 0.4 ng/kg/min, increasing by 0.2 ng/kg/min every hour for 5 h. On one day, exendin-9,39 (300 pmol/kg/min) was infused to block GLP-1R, while on the other, saline was infused. The insulin secretion rate (ISR) was calculated by nonparametric deconvolution from plasma concentrations of C-peptide. Endogenous glucose production and glucose disappearance were measured using the tracer-dilution technique. Glucagon concentrations, by design, did not differ between study days. Integrated ISR was lower during exendin-9,39 infusion (213 ± 26 vs. 191 ± 22 nmol/5 h, saline vs. exendin-9,39, respectively; P = 0.02). In the separate experiment, exendin-9,39 infusion, compared with saline infusion, also decreased the β-cell secretory response to a 1-mg glucagon bolus. These data show that, in humans without diabetes, glucagon partially stimulates the β-cell through GLP-1R.

Projecting the incidence and costs of major cardiovascular and kidney complications of type 2 diabetes with widespread SGLT2i and GLP-1 RA use: a cost-effectiveness analysis

AIMS/HYPOTHESIS

Whether sodium-glucose co-transporter 2 inhibitors (SGLT2is) or glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are cost-effective based solely on their cardiovascular and kidney benefits is unknown. We projected the health and economic outcomes due to myocardial infarction (MI), stroke, heart failure (HF) and end-stage kidney disease (ESKD) among people with type 2 diabetes, with and without CVD, under scenarios of widespread use of these drugs.

METHODS

We designed a microsimulation model using real-world data that captured CVD and ESKD morbidity and mortality from 2020 to 2040. The populations and transition probabilities were derived by linking the Australian Diabetes Registry (1.1 million people with type 2 diabetes) to hospital admissions databases, the National Death Index and the ESKD Registry using data from 2010 to 2019. We modelled four interventions: increase in use of SGLT2is or GLP-1 RAs to 75% of the total population with type 2 diabetes, and increase in use of SGLT2is or GLP-1 RAs to 75% of the secondary prevention population (i.e. people with type 2 diabetes and prior CVD). All interventions were compared with current use of SGLT2is (20% of the total population) and GLP-1 RAs (5% of the total population). Outcomes of interest included quality-adjusted life years (QALYs), total costs (from the Australian public healthcare perspective) and the incremental cost-effectiveness ratio (ICER). We applied 5% annual discounting for health economic outcomes. The willingness-to-pay threshold was set at AU$28,000 per QALY gained.

RESULTS

The numbers of QALYs gained from 2020 to 2040 with increased SGLT2i and GLP-1 RA use in the total population (n=1.1 million in 2020; n=1.5 million in 2040) were 176,446 and 200,932, respectively, compared with current use. Net cost differences were AU$4.2 billion for SGLT2is and AU$20.2 billion for GLP-1 RAs, and the ICERs were AU$23,717 and AU$100,705 per QALY gained, respectively. In the secondary prevention population, the ICERs were AU$8878 for SGLT2is and AU$79,742 for GLP-1 RAs.

CONCLUSIONS/INTERPRETATION

At current prices, use of SGLT2is, but not GLP-1 RAs, would be cost-effective when considering only their cardiovascular and kidney disease benefits for people with type 2 diabetes.

The blood pressure lowering effects of glucagon-like peptide-1 receptor agonists: A mini-review of the potential mechanisms

The incretin hormone glucagon-like peptide 1 (GLP-1) is a key component of the signaling mechanisms promoting glucose homeostasis. Clinical and experimental studies demonstrated that GLP-1 receptor agonists, including GLP-1 itself, have favorable effects on blood pressure and reduce the risk of major cardiovascular events, independently of their effect on glycemic control. GLP-1 receptors are present in the hypothalamus and brainstem, the carotid body, the vasculature, and the kidneys. These organs are involved in blood pressure regulation, have their function altered in hypertension, and are positively benefited by the treatment with GLP-1 receptor agonists. Here, we discuss the potential mechanisms whereby activation of GLP-1R signaling exerts blood pressure-lowering effects beyond glycemic control.

The cardiovascular and renal effects of glucagon-like peptide 1 receptor agonists in patients with advanced diabetic kidney disease

BACKGROUND

To determine whether glucagon-like peptide 1 receptor agonists (GLP-1RAs) have cardiovascular and renal protective effects in patients with advanced diabetic kidney disease (DKD) with an estimated glomerular filtration rate (eGFR) < 30 mL/min per 1.73 m².

METHODS

In this cohort study, patients with type 2 diabetes mellitus and eGFR < 30 mL/min per 1.73 m² with a first prescription for GLP-1RAs or dipeptidyl peptidase 4 inhibitors (DPP-4is) from 2012 to 2021 (n = 125,392) were enrolled. A Cox proportional hazard model was used to assess the cardiorenal protective effects between the GLP-1RA and DDP-4i groups.

RESULTS

A total of 8922 participants [mean (SD) age 68.4 (11.5) years; 4516 (50.6%) males; GLP-1RAs, n = 759; DPP-4is, n = 8163] were eligible for this study. During a mean follow-up of 2.1 years, 78 (13%) and 204 (13.8%) patients developed composite cardiovascular events in the GLP-1RA and DPP-4i groups, respectively [hazard ratio (HR) 0.88, 95% confidence interval CI 0.68-1.13]. Composite kidney events were reported in 134 (38.2%) and 393 (44.2%) patients in the GLP-1RA and DPP-4i groups, respectively (subdistribution HR 0.72, 95% CI 0.56-0.93).

CONCLUSIONS

GLP-1RAs had a neutral effect on the composite cardiovascular outcomes but reduced composite kidney events in the patients with advanced DKD compared with DPP-4is.

Acute Inhibition of Intestinal Neprilysin Enhances Insulin Secretion via GLP-1 Receptor Signaling in Male Mice

The peptidase neprilysin modulates glucose homeostasis by cleaving and inactivating insulinotropic peptides, including some produced in the intestine such as glucagon-like peptide-1 (GLP-1). Under diabetic conditions, systemic or islet-selective inhibition of neprilysin enhances beta-cell function through GLP-1 receptor (GLP-1R) signaling. While neprilysin is expressed in intestine, its local contribution to modulation of beta-cell function remains unknown. We sought to determine whether acute selective pharmacological inhibition of intestinal neprilysin enhanced glucose-stimulated insulin secretion under physiological conditions, and whether this effect was mediated through GLP-1R. Lean chow-fed Glp1r+/+ and Glp1r-/- mice received a single oral low dose of the neprilysin inhibitor thiorphan or vehicle. To confirm selective intestinal neprilysin inhibition, neprilysin activity in plasma and intestine (ileum and colon) was assessed 40 minutes after thiorphan or vehicle administration. In a separate cohort of mice, an oral glucose tolerance test was performed 30 minutes after thiorphan or vehicle administration to assess glucose-stimulated insulin secretion. Systemic active GLP-1 levels were measured in plasma collected 10 minutes after glucose administration. In both Glp1r+/+ and Glp1r-/- mice, thiorphan inhibited neprilysin activity in ileum and colon without altering plasma neprilysin activity or active GLP-1 levels. Further, thiorphan significantly increased insulin secretion in Glp1r+/+ mice, whereas it did not change insulin secretion in Glp1r-/- mice. In conclusion, under physiological conditions, acute pharmacological inhibition of intestinal neprilysin increases glucose-stimulated insulin secretion in a GLP-1R-dependent manner. Since intestinal neprilysin modulates beta-cell function, strategies to inhibit its activity specifically in the intestine may improve beta-cell dysfunction in type 2 diabetes.

The efficacy and safety of combined GLP-1RA and basal insulin therapy among inadequately controlled T2D with premixed insulin therapy

This study investigated the effect of a combination of glucagon-like peptide-1 receptor agonist (GLP-1 RA) and basal insulin (BI) in poorly controlled type 2 diabetes mellitus previously treated with premixed insulin. The possible therapeutic benefit of the subject is mainly hoped to provide a direction for optimizing treatment options to reduce the risk of hypoglycemia and weight gain. A single-arm, open-label study was conducted. The antidiabetic regimen was switched to GLP-1 RA plus BI to replace previous treatment with premixed insulin in type 2 diabetes mellitus subjects. After 3 months of treatment modification, GLP-1 RA plus BI was compared for superior outcomes by continuous glucose monitoring system. There were 34 subjects at the beginning, 4 withdrew due to gastrointestinal discomfort, and finally 30 subjects completed the trial, of which 43% were male; the average age was 58 ± 9 years old, and the average duration of diabetes was 12 ± 6 years, the baseline glycated hemoglobin level was 8.6 ± 0.9 %. The initial insulin dose of premixed insulin was 61 ± 18 units, and the final insulin dose of GLP-1 RA + BI was 32 ± 12 units (P < .001). Time out of range (from 59%-42%), time-in-range (from 39%-56%) as well as glucose variability index including standard deviation also improved, mean magnitude of glycemic excursions, mean daily difference and continuous population in continuous glucose monitoring system, continuous overall net glycemic action (CONGA). Also noted was a decrease in body weight (from 70.9 kg-68.6 kg) and body mass index (all P values < .05). It provided important information for physicians to decide to modify therapeutic strategy as individualized needs.

Use and Interchange of Incretin Mimetics in the Treatment of Metabolic Diseases: A Narrative Review

PURPOSE

Glucagon-like peptide 1 receptor agonists (GLP-1 RAs) and now tirzepatide, a dual GLP-1 RA/glucose-dependent insulinotropic polypeptide agonist, have numerous advantages in the treatment of type 2 diabetes and obesity, yet only 11% of patients with type 2 diabetes are prescribed a GLP-1 RA. This narrative review addresses the complexity and cost issues surrounding incretin mimetics to support clinicians.

METHODS

This narrative review summarizes key trials on the differing effects of incretin mimetics on glycosylated hemoglobin and weight, provides a table with rationale for how to interchange among agents, and summarizes the key factors that guide drug selection beyond guidance from the American Diabetes Association. To support proposed dose interchanges, we preferentially selected high-quality, prospective randomized controlled trials with direct comparisons of agents and doses when available.

FINDINGS

Tirzepatide produces the greatest reductions in glycosylated hemoglobin and weight, but its impact on cardiovascular events is still under investigation. Subcutaneous semaglutide and liraglutide are approved for weight loss specifically and are effective in the secondary prevention of cardiovascular disease. Although producing less weight loss, only dulaglutide has effectiveness in the primary and secondary prevention of cardiovascular disease. Semaglutide is the only orally available incretin mimetic; however, the oral formulation produces less weight loss versus its subcutaneous alternative and did not have cardioprotection in its outcomes trial. Although effective in controlling type 2 diabetes, exenatide extended release has the least impact on glycosylated hemoglobin and weight among commonly used agents, while not having cardioprotection. However, exenatide extended release may be preferred on some restrictive insurance formularies.

IMPLICATIONS

Although trials have not explicitly studied how to interchange among agents, interchanges can be guided by comparisons between agents' impact on glycosylated hemoglobin and weight. Efficient changes among agents can help clinicians optimize patient-centered care, particularly in the face of changing patient needs and preferences, insurance formularies, and drug shortages. (Clin Ther. 2023;XX:XXX-XXX) © 2023 Elsevier HS Journals, Inc.

The Importance of Endogenously Secreted GLP-1 and GIP for Postprandial Glucose Tolerance and β-Cell Function After Roux-en-Y Gastric Bypass and Sleeve Gastrectomy Surgery

Enhanced secretion of glucagon-like peptide 1 (GLP-1) seems to be essential for improved postprandial β-cell function after Roux-en-Y gastric bypass (RYGB) but is less studied after sleeve gastrectomy (SG). Moreover, the role of the other major incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), is relatively unexplored after bariatric surgery. We studied the effects of separate and combined GLP-1 receptor (GLP-1R) and GIP receptor (GIPR) blockade during mixed-meal tests in unoperated (CON), SG-operated, and RYGB-operated people with no history of diabetes. Postprandial GLP-1 concentrations were highest after RYGB but also higher after SG compared with CON. In contrast, postprandial GIP concentrations were lowest after RYGB. The effect of GLP-1R versus GIPR blockade differed between groups. GLP-1R blockade reduced β-cell glucose sensitivity and increased or tended to increase postprandial glucose responses in the surgical groups but had no effect in CON. GIPR blockade reduced β-cell glucose sensitivity and increased or tended to increase postprandial glucose responses in the CON and SG groups but had no effect in the RYGB group. Our results support that GIP is the most important incretin hormone in unoperated people, whereas GLP-1 and GIP are equally important after SG, and GLP-1 is the most important incretin hormone after RYGB.

Hypoglycemia after exposure of diclofenac medication

CONTEXT

Diclofenac is commonly used as pain relief. Hypoglycemia has rarely been reported due to aspirin and indomethacin use but not of any other nonsteroidal anti-inflammatory drugs.

CASE REPORT

A 69-years old endocrinologist participated as a control in a glucagon-like peptide-1 (GLP-1) study. He decreased his plasma glucose to 1.8 mmol/L and developed full-blown hypoglycemic symptoms during an oral glucose tolerance test (OGTT). He had taken a 50 mg diclofenac tablet at 10 pm the evening before for a harmless muscle stretch in the lower back. Apart from well-controlled hypothyroidism he was healthy. During medical school he often had reactive hypoglycemia which came after intake of a carbohydrate rich but otherwise poor breakfast followed by bicycling. However, he had never experienced problems later in life after more decent meals containing slower absorbable carbohydrates. A 3-day continuous glucose monitoring (CGM) was performed three weeks after the OGTT test. A glucose value of 3.1 mmol/L was registered on the third CGM day in the afternoon after intake of 500 mg aspirin in the early morning the same day. Otherwise, all values were normal. A second OGGT where no medications apart from levothyroxine had been taken during at least a 2-week period adjacent was normal. Detailed analyses of the OGTTs showed that the GLP-1 levels before the test were higher after diclofenac exposure while the insulin levels increased after the glucose challenge which suggesting uncoupling.

CONCLUSION

With this case report we would like to draw attention to that diclofenac may cause hypoglycemia.

The Insulin: Glucagon Ratio and Obesity

This communication discusses the physiology and pathology of the insulin glucagon ratio, with respect to obesity. Though high insulin levels are associated with obesity in this manuscript the authors specifically highlight its role in the causation and clinical management of obesity. It suggests that the term insulin glucagon ratio be used in preference to glucagon insulin ratio, and shares insights which may be helpful in informing future research.

Does glucose lowering restore GIP effects on insulin secretion?

AIMS

Some studies have shown that in type 2 diabetic patients the potentiation of insulin secretion by glucose-dependent insulinotropic polypeptide (GIP) is compromised but can be partially restored if glucose is lowered. Renewed interest for this phenomenon has been expressed in the context of the new dual GIP-GLP-1 (glucagon-like peptide-1) receptor agonists, which have shown greater efficacy of this drug class compared with single GLP-1 receptor agonists, including on insulin secretion. However, contrasting evidence has been reported on the recovery of GIP action with glucose lowering. In our study, we reconsider all publications relevant for the problem and analyze the results using a uniform methodology.

DATA SYNTHESIS

We show that, while some contradictions might be explained by heterogeneous analysis methods, it is possible to interpret all the available data coherently and conclude that the effect of glucose lowering is relevant only when glucose concentration is virtually normalized.

CONCLUSIONS

While a significant restoration of GIP action may not occur with some traditional diabetes treatments, GIP action improvement might become relevant when glucose is virtually normalized and could explain part of the success of the double GIP-GLP-1 receptor agonists.

Glucagon-like peptide-1 secretion in people with versus without type 2 diabetes: a systematic review and meta-analysis of cross-sectional studies

AIMS/HYPOTHESIS

The aim of this systematic review was to synthesise the study findings on whether GLP-1 secretion in response to a meal tolerance test is affected by the presence of type 2 diabetes (T2D). The influence of putative moderators such as age, sex, meal type, meal form, and assay type were also explored.

METHODS

A literature search identified 32 relevant studies. The sample mean and SD for fasting GLP-1TOTAL and GLP-1TOTAL iAUC were extracted and used to calculate between-group standardised mean differences (SMD), which were meta-analysed using a random-effects model to derive pooled estimates of Hedges' g and 95 % prediction intervals (PI).

RESULTS

Pooled across 18 studies, the overall SMD in GLP-1TOTAL iAUC between individuals with T2D (n = 270, 1047 ± 930 pmol·L-1·min) and individuals without T2D (n = 402, 1204 ± 937 pmol·L-1·min) was very small, not statistically significant and heterogenous across studies (g = -0.15, p = 0.43, PI: -1.53, 1.23). Subgroup analyses demonstrated an effect of assay type whereby Hedges' g for GLP-1 iAUC was greater in individuals with, versus those without T2D when using ELISA or Mesoscale (g = 0.67 [moderate], p = 0.009), but not when using RIA (g = -0.30 [small], p = 0.10). Pooled across 30 studies, the SMD in fasting GLP-1TOTAL between individuals with T2D (n = 580, 16.2 ± 6.9 pmol·L-1) versus individuals without T2D (n = 1363, 12.4 ± 5.7 pmol·L-1) was small and heterogenous between studies (g = 0.24, p = 0.21, PI: -1.55, 2.02).

CONCLUSIONS

Differences in fasting GLP-1TOTAL and GLP-1TOTAL iAUC between individuals with, versus those without T2D were generally small and inconsistent between studies. Factors influencing study heterogeneity such as small sample sizes and poor matching of groups may help to explain the wide prediction intervals observed. Considerations to improve comparisons of GLP-1 secretion in T2D and potential mediating factors more important than T2D diagnosis per se are outlined.

PROSPERO ID

CRD42020195612.

Increased expression of glucagon-like peptide-1 and cystic fibrosis transmembrane conductance regulator in the ileum and colon in mouse treated with metformin

Metformin, an oral medication, is prescribed to patients with type 2 diabetes mellitus. Although the efficacy, safety, and low economic burden of metformin on patients have long been recognized, approximately 5% of the patients treated with this drug develop severe diarrhea and discontinue the treatment. We previously reported that 1,000 mg·kg^-1·day^-1 of metformin induced diarrhea in diabetic obese (db/db) mice and wood creosote (traditional medication for diarrhea) ameliorated the symptoms. In this study, we attempted to elucidate the molecular mechanisms by which metformin induces diarrhea. Cystic fibrosis transmembrane conductance regulator (CFTR) is a key ion (chloride) channel in cyclic adenosine monophosphate (cAMP)-induced diarrhea. Metformin treatment increased bile flow (bile acids and bilirubin) in the ileum of mice. In addition, the treatment was accompanied by an increase in mRNA and protein levels of CFTR in the mucosa of the ileum and colon in both wild-type (C57BL/6J) and db/db mice. Glucagon-like peptide-1 (GLP-1), as well as cholic acid, induces CFTR mRNA expression in human colon carcinoma Caco-2 cells through cAMP signaling. Although wood creosote (10 mg/kg) ameliorated diarrhea symptoms, it did not alter the mRNA levels of Glp-1 or Cftr. Similar to overeating, metformin upregulated GLP-1 and CFTR expression, which may have contributed to diarrhea symptoms in mice. Although we could not identify db/db mouse-specific factors associated with metformin-induced diarrhea, these factors may modulate colon function. Wood creosote may not interact with these factors but ameliorates diarrhea symptoms.