Use of incretin-based medications: what do current international recommendations suggest with respect to GLP-1 receptor agonists and DPP-4 inhibitors?

Solid-state fermentation of green lentils by Lactiplantibacillus plantarum leads to formation of distinct peptides that are absorbable and enhances DPP-IV inhibitory activity in an intestinal Caco-2 cell model

Food-derived bioactive compounds mimicking the effects of incretin therapies offer promising opportunities for combination therapies with functional foods, where food matrix interactions, gastrointestinal enzyme activity, and in situ bioactivity should be key considerations. In this study, green lentils were solid-state fermented with Lactiplantibacillus plantarum ATCC8014, in vitro digested and exposed to brush border enzymes of a Caco-2 cell monolayer. Intestinal absorption of peptides and DPP-IV inhibitory activity were then investigated. LC-MS/MS profiles showed that peptides mainly originated from parental proteins of the vicilin, convicilin and legumin families. Fermentation led to the formation of more hydrophobic peptides when compared to the unfermented flour and up to 33.6% of them were transported to the basolateral side of a Caco-2 cell monolayer. Peptides with more than 22 amino acids and with a mass greater than 2000 Da were minimally transported. 73 peptides were uniquely identified in the basolateral fraction suggesting that they resulted from the activity of the brush border enzymes. The DPP-IV activity of Caco-2 cells grown as a polarized monolayer was decreased by 37.3% when exposed to in vitro digested 72 h-fermented lentil flour and 10% when exposed to the unfermented one. Inhibition of DPP-IV in the basolateral fluids was improved in a dose-dependent manner and reached 7.9% when 500 mg mL-1 of in vitro digested 72 h fermented lentil flour was used. Glucose absorption and uptake were minimally affected, suggesting that the previously observed hypoglycemic properties of lentils are likely due to activity on DPP-IV rather than on the inhibition of glucose absorption.

Early type 2 diabetes treatment intensification with glucagon-like peptide-1 receptor agonists in primary care: An Australian perspective on guidelines and the global evidence

Early and intensive management of type 2 diabetes has been shown to delay disease progression, reduce the risk of cardiorenal complications and prolong time to treatment failure. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are being increasingly recognized for their potential in early disease management, with recent guideline updates recommending second-line use of this injectable drug class alongside oral glucose-lowering drugs. GLP-1RAs target at least six of the eight core defects implicated in the pathogenesis of type 2 diabetes and offer significant glycaemic and weight-related improvements over other second-line agents in head-to-head trials. In addition, placebo-controlled clinical trials have shown cardiovascular protection with GLP-1RA use. Even so, this therapeutic class is underused in primary care, largely owing to clinical inertia and patient-related barriers to early intensification with GLP-1RAs. Fortunately, clinicians can overcome barriers to treatment acceptance through patient education and training, and management of treatment expectations. In this review we comment on global and Australian guideline updates and evidence in support of early intensification with this therapeutic class, and provide clinicians with practical advice for GLP-1RA use in primary care.

Assessing real-world effectiveness of therapies: what is the impact of incretin-based treatments on hospital use for patients with type 2 diabetes?

BACKGROUND

Managing type 2 diabetes represents a major public health concern due to its important and increasing prevalence. Our study investigates the impact of taking incretin-based medication on the risk of being hospitalized and the length of hospital stay for individuals with type 2 diabetes.

METHOD

We use claim panel data from 2011 to 2015 and provide difference-in-differences (DID) estimations combined with matching techniques to better ensure the treatment and control groups' comparability. Our propensity score selects individuals according to their probability of taking an incretin-based treatment in 2013 (N = 2,116). The treatment group includes individuals benefiting from incretin-based treatments from 2013 to 2015 and is compared to individuals not benefiting from such a treatment but having a similar probability of taking it.

RESULTS

After controlling for health-related and socio-economic variables, we show that benefiting from an incretin-based treatment does not significantly impact the probability of being hospitalized but does significantly decrease the annual number of days spent in the hospital by a factor rate of 0.621 compared with the length of hospital stays for patients not benefiting from such a treatment.

CONCLUSION

These findings highlight the potential implications for our health care system in case of widespread use of these drugs among patients with severe diabetes.

Role of Dipeptidyl Peptidase-4 (DPP4) on COVID-19 Physiopathology

DPP4/CD26 is a single-pass transmembrane protein with multiple functions on glycemic control, cell migration and proliferation, and the immune system, among others. It has recently acquired an especial relevance due to the possibility to act as a receptor or co-receptor for SARS-CoV-2, as it has been already demonstrated for other coronaviruses. In this review, we analyze the evidence for the role of DPP4 on COVID-19 risk and clinical outcome, and its contribution to COVID-19 physiopathology. Due to the pathogenetic links between COVID-19 and diabetes mellitus and the hyperinflammatory response, with the hallmark cytokine storm developed very often during the disease, we dive deep into the functions of DPP4 on carbohydrate metabolism and immune system regulation. We show that the broad spectrum of functions regulated by DPP4 is performed both as a protease enzyme, as well as an interacting partner of other molecules on the cell surface. In addition, we provide an update of the DPP4 inhibitors approved by the EMA and/or the FDA, together with the newfangled approval of generic drugs (in 2021 and 2022). This review will also cover the effects of DPP4 inhibitors (i.e., gliptins) on the progression of SARS-CoV-2 infection, showing the role of DPP4 in this disturbing disease.

Investigating Potential GLP-1 Receptor Agonists in Cyclopeptides from Pseudostellaria heterophylla, Linum usitatissimum, and Drymaria diandra, and Peptides Derived from Heterophyllin B for the Treatment of Type 2 Diabetes: An In Silico Study

GLP-1 receptor agonists stimulate GLP-1R to promote insulin secretion, whereas DPP4 inhibitors slow GLP-1 degradation. Both approaches are incretin-based therapies for T2D. In addition to GLP-1 analogs, small nonpeptide GLP-1RAs such as LY3502970, TT-OAD2, and PF-06882961 have been considered as possible therapeutic alternatives. Pseudostellaria heterophylla, Linum usitatissimum, and Drymaria diandra are plants rich in cyclopeptides with hypoglycemic effects. Our previous study demonstrated the potential of their cyclopeptides for DPP4 inhibition. Reports of cyclic setmelanotide as an MC4R (GPCR) agonist and cyclic α-conotoxin chimeras as GLP-1RAs led to docking studies of these cyclopeptides with GLP-1R. Heterophyllin B, Pseudostellarin B, Cyclolinopeptide B, Cyclolinopeptide C, Drymarin A, and Diandrine C are abundant in these plants, with binding affinities of −9.5, −10.4, −10.3, −10.6, −11.2, and −11.9 kcal/mol, respectively. The configuration they demonstrated established multiple hydrogen bonds with the transmembrane region of GLP-1R. DdC:(cyclo)-GGPYWP showed the most promising docking score. The results suggest that, in addition to DPP4, GLP-1R may be a hypoglycemic target of these cyclopeptides. This may bring about more discussion of plant cyclopeptides as GLP-1RAs. Moreover, peptides derived from the HB precursor (IFGGLPPP), including IFGGWPPP, IFPGWPPP, IFGGYWPPP, and IFGYGWPPPP, exhibited diverse interactions with GLP-1R and displayed backbones available for further research.

Efficacy of Semaglutide in a Subcutaneous and an Oral Formulation

Despite the benefits of early and effective glycemic control in the management of type 2 diabetes (T2D), achieving glycated hemoglobin (HbA1c) targets is challenging in some patients. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) provide effective reductions in HbA1c and body weight. Semaglutide is the only GLP-1RA that is available in both an injectable and oral formulation. The efficacy of once-weekly subcutaneous semaglutide and once-daily oral semaglutide has been investigated in the global SUSTAIN and PIONEER phase III clinical trial programs in a range of clinical settings, including early T2D managed with diet and exercise only, more established T2D uncontrolled on one to three oral antidiabetic drugs, and advanced disease treated with insulin. Across the SUSTAIN program, once-weekly subcutaneous semaglutide 1.0 mg reduced HbA1c by 1.5-1.8% after 30-56 weeks, which was significantly more than sitagliptin, liraglutide, exenatide extended release, dulaglutide, canagliflozin, or insulin glargine. Across the PIONEER program, once-daily oral semaglutide 14 mg reduced HbA1c by 1.0-1.4%, significantly more than sitagliptin or empagliflozin, and to a similar extent as liraglutide after 26 weeks. In addition, subcutaneous semaglutide reduced body weight significantly more than all active comparators tested, while oral semaglutide reduced body weight more than sitagliptin and liraglutide, and to a similar extent as empagliflozin. Neither formulation of semaglutide has been associated with an increased risk of hypoglycemia and both improve various measures of health-related quality of life. Semaglutide offers the benefits of a highly effective GLP-1RA in both injectable and oral formulations. Selection of the most appropriate formulation can be made on an individual basis to best suit the patient's preferences and needs.

Mechanisms of Beta-Cell Apoptosis in Type 2 Diabetes-Prone Situations and Potential Protection by GLP-1-Based Therapies

Type 2 diabetes (T2D) is characterized by chronic hyperglycemia secondary to the decline of functional beta-cells and is usually accompanied by a reduced sensitivity to insulin. Whereas altered beta-cell function plays a key role in T2D onset, a decreased beta-cell mass was also reported to contribute to the pathophysiology of this metabolic disease. The decreased beta-cell mass in T2D is, at least in part, attributed to beta-cell apoptosis that is triggered by diabetogenic situations such as amyloid deposits, lipotoxicity and glucotoxicity. In this review, we discussed the molecular mechanisms involved in pancreatic beta-cell apoptosis under such diabetes-prone situations. Finally, we considered the molecular signaling pathways recruited by glucagon-like peptide-1-based therapies to potentially protect beta-cells from death under diabetogenic situations.

Long-Term Dipeptidyl Peptidase 4 Inhibition Worsens Hypertension and Renal and Cardiac Abnormalities in Obese Spontaneously Hypertensive Heart Failure Rats

Background The long-term effects of dipeptidyl peptidase 4 (DPP4) inhibitors on blood pressure and cardiovascular and renal health remain controversial. Herein, we investigated the extended (>182 days) effects of DPP4 inhibition in a model of spontaneous hypertension, heart failure, diabetes mellitus, obesity and hyperlipidemia. Methods and Results Adult obese spontaneously hypertensive heart failure rats (SHHF) were implanted with radio transmitters for measurement of arterial blood pressures. Two weeks later, SHHF were randomized to receive either a DPP4 inhibitor (sitagliptin, 80 mg/kg per day in drinking water) or placebo. At the end of the radiotelemetry measurements, renal and cardiac function and histology, as well as other relevant biochemical parameters, were assessed. For the first 25 days, mean arterial blood pressures were similar in sitagliptin-treated versus control SHHF; afterwards, mean arterial blood pressures increased more in sitagliptin-treated SHHF (P<0.000001). The time-averaged mean arterial blood pressures from day 26 through 182 were 7.2 mm Hg higher in sitagliptin-treated SHHF. Similar changes were observed for systolic (8.6 mm Hg) and diastolic (6.1 mm Hg) blood pressures, and sitagliptin augmented hypertension throughout the light-dark cycle. Long-term sitagliptin treatment also increased kidney weights, renal vascular resistances, the excretion of kidney injury molecule-1 (indicates injury to proximal tubules), renal interstitial fibrosis, glomerulosclerosis, renal vascular hypertrophy, left ventricular dysfunction, right ventricular degeneration, and the ratios of collagen IV/collagen III and collagen IV/laminin in the right ventricle. Conclusions These findings indicate that, in some genetic backgrounds, long-term DPP4 inhibitor treatment is harmful and identify an animal model to study mechanisms of, and test ways to prevent, DPP4 inhibitor-induced pathological conditions.

Nocturnal Hypoglycaemia in Patients with Diabetes Mellitus: Database Analysis of a Cohort Using Telemedicine Support for Self-Monitoring of Blood Glucose over a 10-Year-Long Period

Background and Objectives: In patients with diabetes mellitus, hypoglycaemic episodes, especially during night hours, carry a significant risk. Data about the occurrence of nocturnal hypoglycaemia in real-world settings are of clinical importance. The aim of our study was to evaluate the occurrence of nocturnal hypoglycaemia among patients with diabetes using self-monitoring of blood glucose (SMBG) with telemedicine support. Materials and Methods: We retrospectively analysed the central database of an internet-based supportive system between 2010 and 2020 when 8190 SMBG users uploaded nearly 10 million capillary blood glucose values. Nocturnal hypoglycaemia was defined as capillary blood glucose < 3.0 mmol/L measured between 00:00 and 05:59 h. Results: The database contained 914,146 nocturnal blood glucose values from 7298 users; 24,623 (2.7%) glucose values were below the hypoglycaemic threshold and 2363 patients (32.4%) had at least one hypoglycaemic glucose value. Nocturnal hypoglycaemia was more often found in patients with type 1 vs. type 2 diabetes (n = 1890 (80.0%) vs. n = 387 (16.4%), respectively). Hypoglycaemic blood glucose values were most frequently observed in the age group of 10.0–19.9 years (n = 481 (20.4%)). Patients with nocturnal hypoglycaemia were mostly on insulin treatment (1854 (78.5%) patients with 20,727 (84.1%) hypoglycaemic glucose values). Only 356 patients (15.1%) with nocturnal hypoglycaemia performed a retest within 120 min. Within a one-day-long (1440 min) timeframe, the elapsed median time until a retest, yielding a safe blood glucose value (>3.9 mml/L), was 273 min (interquartile range: 157–300 min). Conclusions: Nocturnal hypoglycaemia should be considered as a persisting challenge to antihyperglycaemic treatment in patients living with diabetes. Continuous efforts are needed to improve both antihyperglycaemic treatment and patient education for preventing nocturnal hypoglycaemia, and to act adequately if hypoglycaemic values are detected.

Incretin Hormones in Obesity and Related Cardiometabolic Disorders: The Clinical Perspective

The prevalence of obesity continues to grow rapidly worldwide, posing many public health challenges of the 21st century. Obese subjects are at major risk for serious diet-related noncommunicable diseases, including type 2 diabetes mellitus, cardiovascular disease, and non-alcoholic fatty liver disease. Understanding the mechanisms underlying obesity pathogenesis is needed for the development of effective treatment strategies. Dysregulation of incretin secretion and actions has been observed in obesity and related metabolic disorders; therefore, incretin-based therapies have been developed to provide new therapeutic options. Incretin mimetics present glucose-lowering properties, together with a reduction of appetite and food intake, resulting in weight loss. In this review, we describe the physiology of two known incretins—glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), and their role in obesity and related cardiometabolic disorders. We also focus on the available and incoming incretin-based medications that can be used in the treatment of the above-mentioned conditions.

Clinical Perspectives on the Use of Subcutaneous and Oral Formulations of Semaglutide

Early and effective glycemic control can prevent or delay the complications associated with type 2 diabetes (T2D). The benefits of glucagon-like peptide-1 receptor agonists (GLP-1RAs) are becoming increasingly recognized and they now feature prominently in international T2D treatment recommendations and guidelines across the disease continuum. However, despite providing effective glycemic control, weight loss, and a low risk of hypoglycemia, GLP-1RAs are currently underutilized in clinical practice. The long-acting GLP-1RA, semaglutide, is available for once-weekly injection and in a new once-daily oral formulation. Semaglutide is an advantageous choice for the treatment of T2D since it has greater efficacy in reducing glycated hemoglobin and body weight compared with other GLP-1RAs, has demonstrated benefits in reducing major adverse cardiovascular events, and has a favorable profile in special populations (e.g., patients with hepatic impairment or renal impairment). The oral formulation represents a useful option to help improve acceptance and adherence compared with injectable formulations for patients with a preference for oral therapy, and may lead to earlier and broader use of GLP-1RAs in the T2D treatment trajectory. Oral semaglutide should be taken on an empty stomach, which may influence the choice of formulation. As with most GLP-1RAs, initial dose escalation of semaglutide is required for both formulations to mitigate gastrointestinal adverse events. There are also specific dose instructions to follow with oral semaglutide to ensure sufficient gastric absorption. The evidence base surrounding the clinical use of semaglutide is being further expanded with trials investigating effects on diabetic retinopathy, cardiovascular outcomes, and on the common T2D comorbidities of obesity, chronic kidney disease, and non-alcoholic steatohepatitis. These will provide further information about whether the benefits of semaglutide extend to these other indications.

Pyrazole Incorporated New Thiosemicarbazones: Design, Synthesis and Investigation of DPP-4 Inhibitory Effects

Dipeptidyl peptidase-4 (DPP-4) inhibition has been recognized as a promising approach to develop safe and potent antidiabetic agents for the management of type 2 diabetes. In this context, new thiosemicarbazones (2a-o) were prepared efficiently by the reaction of aromatic aldehydes with 4-[4-(1H-pyrazol-1-yl)phenyl]thiosemicarbazide (1), which was obtained via the reaction of 4-(1H-pyrazol-1-yl)phenyl isothiocyanate with hydrazine hydrate. Compounds 2a-o were evaluated for their DPP-4 inhibitory effects based on a convenient fluorescence-based assay. 4-[4-(1H-pyrazol-1-yl)phenyl]-1-(4-bromobenzylidene)thiosemicarbazide (2f) was identified as the most effective DPP-4 inhibitor in this series with an IC₅₀ value of 1.266 ± 0.264 nM when compared with sitagliptin (IC₅₀ = 4.380 ± 0.319 nM). MTT test was carried out to assess the cytotoxic effects of compounds 2a-o on NIH/3T3 mouse embryonic fibroblast (normal) cell line. According to cytotoxicity assay, compound 2f showed cytotoxicity towards NIH/3T3 cell line with an IC₅₀ value higher than 500 µM pointing out its favourable safety profile. Molecular docking studies indicated that compound 2f presented π-π interactions with Arg358 and Tyr666 via pyrazole scaffold and 4-bromophenyl substituent, respectively. Overall, in vitro and in silico studies put emphasis on that compound 2f attracts a great notice as a drug-like DPP-4 inhibitor for further antidiabetic research.

Appetite control: hormones or diet strategies?

PURPOSE OF REVIEW

Appetite control results from metabolic, behavioral, and environmental factors that influence hunger and the desire to eat. We summarize the latest advances in the hormonal and nutritional strategies to control appetite and reduce hunger.

RECENT FINDINGS

The fed-hunger-state is regulated by central and peripheric hormones, which modulate energy balance. Leptin, insulin, ghrelin, peptide YY (PYY), and other gut-derived peptides represent the main appetite controllers. The role of orexins, obestatin, and liver-expressed antimicrobial peptide 2 has been uncovered recently. New insights have demonstrated the role of hippocampal activity as a possible mechanism of action. Glucagon-like peptide 1 (GLP1) receptor agonists are well known agents controlling appetite. Association of GLP1 receptor agonist, PYY, or glucose-dependent insulinotropic polypeptide agonists have been tested as new approaches. Appetite-control hormones have also risen as factors involved in the efficacy of bariatric procedures. High-protein, ketogenic diet, and intermittent fasting have been described as nutritional strategies to reduce appetite, although the physiological mechanism and long-term safety remains unclear.

SUMMARY

Appetite control has been an important target for the treatment of obesity and associated disorders. New studies have demonstrated promising adoption of dietary approaches, hormone-based drugs, and bariatric surgery to control energy intake. Further research will establish a significant association, benefits, and safety of these new therapies.