A review of newer treatment approaches for type-2 diabetes: Focusing safety and efficacy of incretin based therapy

Discovery and functional mechanism of novel dipeptidyl peptidase Ⅳ inhibitory peptides from Chinese traditional fermented fish (Chouguiyu)

Dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides from fermented foods exhibit great potential to alleviate type 2 diabetes mellitus (T2DM). In this study, the DPP-IV inhibition activity of peptide extract from Chouguiyu was obviously enhanced after 4–8 d fermentation. A total of 125 DPP-IV inhibitory peptides in Chouguiyu were identified by peptidomics and were obtained from 46 precursor proteins, mainly including nebulin, titin, muscle-type creatine kinase, hemoglobin, and actin. After molecular docking with DPP-IV, four novel DPP-IV inhibitory peptides possessing the lowest docking energy were selected, including EPAEAVGDWR (D37), IPHESVDVIK (D22), PDLSKHNNHM (D35), and PFGNTHNNFK (D1). The DPP-IV inhibition activity of D37, D22, D35, and D1 were further verified after synthesis with the IC₅₀ of 0.10 mM, 2.69 mM, 3.88 mM, and 8.51 mM, respectively, in accordance with their docking energies. Energy interaction showed that the structures of EP-, IPH-, -NHM, and PF- in these peptides were easy to connect with DPP-IV enzyme through hydrogen bond, salt bridge, and alkyl. The surface force including the H-bond interaction, hydrophobicity, aromatic interaction, and SAS, played a major role in the interaction between DPP-IV enzyme and peptides. The peptides that possess high hydrophobicity and can form strong hydrogen bond and salt bridge are potential DPP-IV inhibitory peptides using for T2DM remission.

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DPP-Ⅳ inhibition activity of peptide extract in Chouguiyu increased by fermentation.

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The main precursor proteins of DPP-Ⅳ inhibitory peptides were nebulin and titin.

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Inhibition mechanism was explored by energy interaction and surface force.

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Docking energy was an effective index to select DPP-IV inhibitory peptides.

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DPP-IV inhibitory peptides formed hydrogen bond and salt bridge with DPP-IV.

Prevalence of Bacterial Urinary Tract Infection Among Patients With Type 2 Diabetes Mellitus on Sodium-Glucose Cotransporter-2 Inhibitors: A Prospective Real-World Setting Study

Background

Genitourinary tract infections, mycotic as well as bacterial, as defined by clinical symptoms, are one of the common adverse effects associated with the use of sodium-glucose cotransporter-2 inhibitors (SGLT2i) in type 2 diabetes mellitus (T2DM) patients in clinical trials. However, Indian data in terms of the prevalence of culture-proven bacterial type of urinary tract infection (UTI), and the causative organism is limited.

Objective

This study aimed to determine the prevalence and causative agents of bacterial UTI among patients with T2DM on SGLT2i.

Methodology

This was a prospective longitudinal study involving all patients with T2DM who were prescribed with SGLT2i, uncontrolled on other oral anti-diabetic medications, from June 2019 to February 2020. Prevalence of bacterial UTI was evaluated at baseline and 12 weeks after initiation of SGLT2i.

Results

A total of 80 patients were started on SGLT2i. One female patient on canagliflozin had significant asymptomatic bacteriuria and the causative agent was Acinetobacter baumannii. One male patient on dapagliflozin had symptomatic UTI with negative urine culture study. Four patients developed genital mycotic infection.

Conclusion

In this real-world study, SGLT2i as a class, was well tolerated with favorable safety profile, and risk of developing significant bacteriuria and/or symptomatic UTI was minimal.

Design and biological evaluation of tetrahydropyridine derivatives as novel human GPR119 agonists

A series of novel tetrahydropyridine derivatives were prepared and evaluated using cell-based measurements. Systematic optimization of general structure G-1 led to the identification of compound 35 (EC₅₀ = 4.9 nM) and 37 (EC₅₀ = 8.8 nM) with high GPR119 agonism activity and moderate clog P. Through single and long-term pharmacodynamic experiments, we found that compound35 showed a hypoglycemic effect and may have an effect on improving basal metabolic rate in DIO mice. Both in vitro and in vivo tests indicated that compound 35 was a potential potent GPR119 agonist in allusion to T2DM treatment.

Dipeptidyl peptidase-4 inhibitors and risk of arthralgia: A systematic review and meta-analysis

BACKGROUND

The US Food and Drug Administration has warned that treatment with dipeptidyl peptidase (DPP)-4 inhibitors may promote serious arthralgia. However, the clinical evidence for this is relatively lacking.

OBJECTIVE

For this reason, a systematic review and meta-analysis of randomized controlled trials (RCTs) were carried out to determine the relationship between DPP-4 inhibitors and risk of arthralgia, and also to investigate any potential risk factors.

METHODS

An extensive electronic search for RCTs comparing DPP-4 inhibitors with any comparators was performed up to July 2016. Outcomes of interest were overall and serious arthralgia. Summary risk ratios (RRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 67 RCTs (involving 79,110 patients) was ultimately included. Pooled results showed that DPP-4 inhibitors were associated with a slightly but significantly increased risk of overall arthralgia (RR: 1.13, 95% CI: 1.04-1.22; P=0.003) and a non-significant increased risk of serious arthralgia (RR: 1.44, 95% CI: 0.83-2.51; P=0.20). Also, subgroup analyses showed that add-on/combination therapy and longer diabetes duration (>5years) were possible factors associated with the increased risk of overall arthralgia.

CONCLUSION

These findings suggest that DPP-4 inhibitors can increase the risk of arthralgia. Thus, the benefits of glycaemic control must be weighed against the risk of arthralgia when prescribing DPP-4 inhibitors. Further studies are now needed to identify and confirm these risk factors.

Effect of exenatide after short-time intensive insulin therapy on glycaemic remission maintenance in type 2 diabetes patients: a randomized controlled trial

Early short-term intensive insulin (STII) therapy can induce drug-free glycemic remission for up to 1 year in half of newly diagnosed type 2 diabetic mellitus (T2DM) patients. Whether exenatide following STII therapy will induce higher long-term glycaemic remission is currently unknown. To assess the effect of STII+ exenatide therapy, compared with STII only, on maintenance of glycaemic remission in newly diagnosed T2DM patients. In this randomized, parallel-group, open-label, controlled trial, 129 patients (66 in STII+ exenatide group and 63 in STII only group) firstly completed 3-week STII therapy, then STII+ exenatide group was treated with exenatide for 12 weeks further. The cumulative probabilities of 1-year and 2-year glycaemic remission in STII+ exenatide group were 68.2 ± 5.7% and 53.0 ± 6.1%, which were significantly higher than STII only group (36.5 ± 6.1% and 31.8 ± 5.9%) (p-values < 0.001). Patients in STII+ exenatide group, compared with STII only group, showed significantly decreased levels of waist (82.2 (81.0, 83.5) cm v.s. 84.2 (82.7, 85.7) cm, p = 0.048) and HbA1c (5.83 (5.60, 6.06)% v.s. 6.49 (6.20, 6.77)%, p < 0.001) after 12-week exenatide treatment, but these differences disappeared after 1-year and 2-year follow-up. As conclusions, Improved effect of sequential exenatide after STII therapy on maintenance of glycaemic remission only occurred during exenatide treatment and lost upon treatment cessation.

Mechanisms of the amplifying pathway of insulin secretion in the β cell

Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.

Long-Term Efficacy and Safety of Empagliflozin Monotherapy in Drug-Naïve Patients with Type 2 Diabetes in Indian Subgroup: Results from a 76-week Extension Trial of Phase III, Double-Blind, Randomized Study

BACKGROUND AND OBJECTIVES

Empagliflozin, a sodium glucose cotransporter-2 inhibitor, was recently evaluated in a randomized, controlled trial (RCT) in drug-naïve Type 2 diabetes mellitus (T2DM) patients managed on diet and exercise therapy. Efficacy and safety of empagliflozin in Indian subgroup of patients from a 76-week extension study of the initial multicentric RCT are reported in this article.

MATERIALS AND METHODS

In this study, patients were randomized to empagliflozin 10 mg (E10, n = 24), empagliflozin 25 mg (E25, n = 29), placebo (n = 28) and sitagliptin 100 mg (S100, n = 27). Exploratory efficacy endpoints were changed from baseline to week 76 in glycosylated hemoglobin (HbA1c, %) and fasting blood glucose (mg/dL) along with body weight (kg) and blood pressure (BP) (mmHg) reduction. Safety analysis included clinically relevant adverse events (AEs).

RESULTS

In 108 randomized patients, adjusted mean reduction in HbA1c compared to placebo was significant with E10 (-0.81, 95% confidence interval (CI) -1.33, -0.28; P = 0.0029) and E25 (-1.11, 95% CI - 1.60, -0.61; P < 0.0001). HbA1c below 7% at week 76 was achieved in significantly higher number of patients with E10 (20.8%, P < 0.0001) and E25 (28.0%, P < 0.0001). There was significant reduction in adjusted mean weight as compared to placebo with E10 (-1.41, 95% CI - 2.51, -0.31; P = 0.0125) and E25 (-1.50, 95% CI - 2.54, -0.46; P = 0.0051) but nonsignificant with S100 (-0.75 95% CI - 1.86, -0.36; P = 0.1842). BP reduction was numerically higher with empagliflozin compared to placebo. AEs were similar in all treatment groups except for genital infections which were more common in E10 (20.8%) but not in E25 (3.4%) as compared to placebo (3.6%). All treatments were well tolerated with no severe AEs.

CONCLUSION

Treatment with empagliflozin was well tolerated and resulted in sustained glycemic efficacy over long-term (76 weeks) in drug-naïve Indian T2DM patients.

A review of glycemic efficacy of liraglutide once daily in achieving glycated hemoglobin targets compared with exenatide twice daily, or sitagliptin once daily in the treatment of type 2 diabetes

Incretin-based therapies such as glucagon-like peptide-1 (GLP-1) receptor agonists (RA) and dipeptidyl peptidase-4 (DPP-4) inhibitors have gained prominence in recent years for the treatment of type 2 diabetes (T2D). Such therapies offer the potential to stimulate endogenous insulin activity in proportion to circulating glucose levels; thereby, lowering the risk of hypoglycemic episodes. The synthetic GLP-1 RA exenatide, the human GLP-1 RA liraglutide, and the DPP-4 inhibitor sitagliptin are the first agents in their respective classes to be approved for the treatment of T2D and their efficacy and safety has been studied extensively in clinical trials. This article reviewed the efficacy of liraglutide once daily in achieving clinical guidelines-recommended glycated hemoglobin A1c levels in patients with T2D compared with exenatide twice daily, or sitagliptin once daily, based on published literature, with an aim to elucidate the preferred choice of incretin-related therapy in treating uncontrolled T2D.

The incretin system ABCs in obesity and diabetes - novel therapeutic strategies for weight loss and beyond

Incretins are gastrointestinal-derived hormones released in response to a meal playing a key role in the regulation of postprandial secretion of insulin (incretin effect) and glucagon by the pancreas. Both incretins, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 (GLP-1), have several other actions by peripheral and central mechanisms. GLP-1 regulates body weight by inhibiting appetite and delaying gastric, emptying actions that are dependent on central nervous system GLP-1 receptor activation. Several other hormones and gut peptides, including leptin and ghrelin, interact with GLP-1 to modulate appetite. GLP-1 is rapidly degraded by the multifunctional enzyme dipeptidyl peptidase-4 (DPP-4). DPP-4 is involved in adipose tissue inflammation, which is associated with insulin resistance and diabetes progression, being a common pathophysiological mechanism in obesity-related complications. Furthermore, the incretin system appears to provide the basis for understanding the high weight loss efficacy of bariatric surgery, a widely used treatment for obesity, often in association with diabetes. The present review brings together new insights into obesity pathogenesis, integrating GLP-1 and DPP-4 in the complex interplay between obesity and inflammation, namely, in diabetic patients. This in turn will provide the basis for novel incretin-based therapeutic strategies for obesity and diabetes with promising benefits in addition to weight loss. © 2016 World Obesity.

Brain signaling systems in the Type 2 diabetes and metabolic syndrome: promising target to treat and prevent these diseases

The changes in the brain signaling systems play an important role in etiology and pathogenesis of Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MS), being a possible cause of these diseases. Therefore, their restoration at the early stages of T2DM and MS can be regarded as a promising way to treat and prevent these diseases and their complications. The data on the functional state of the brain signaling systems regulated by insulin, IGF-1, leptin, dopamine, serotonin, melanocortins and glucagon-like peptide-1, in T2DM and MS, are analyzed. The pharmacological approaches to restoration of these systems and improvement of insulin sensitivity, energy expenditure, lipid metabolism, and to prevent diabetic complications are discussed.

GLP-1 Receptor Agonist Exenatide Attenuates the Detrimental Effects of Obesity on Inflammatory Profile in Testis and Sperm Quality in Mice

PROBLEM

Male obesity has been linked to subfecundity. This study is to investigate the effects of GLP-1 receptor (GLP-1R) agonist exenatide on sperm quality in high-fat diet (HFD)-induced obese mice.

METHOD OF STUDY

After 12 weeks of chow diet (CD) or HFD challenge, mice on HFD were allocated to either saline or exenatide (24 nmol/kg/day) interventions for 8 weeks. Sperm quality and the inflammatory profile of testis were compared among three groups.

RESULTS

Obesity reduced the quality of sperm and changed the inflammatory profile characterized by increased mRNA expression levels of TNF-α, MCP-1, and F4/80 in testis. Exenatide intervention reduced the expression of pro-inflammatory cytokines and improved the quality of sperm.

CONCLUSION

HFD-induced obesity leads to the impairment of sperm quality and increased inflammation of testis in mice, and the abnormal physiology can be attenuated by exenatide treatment. Exenatide treatment may bring additional profits to obese and diabetes men by improving sperm function.

Exenatide once-weekly injection for the treatment of type 2 diabetes in Chinese patients: current perspectives

Glucagon-like peptide-1 (GLP-1) analogs, such as exenatide, have played an important role as antidiabetic medications in the treatment of type 2 diabetes (T2DM). Like most other hypoglycemic agents, exenatide has a number of actions, including lowering blood glucose, promoting weight loss, improving insulin resistance, and protecting islet β-cells. Although GLP-1 analogs, combined with other antidiabetic medications, have excellent performance in T2DM, some side effects and imperfections limit its use in clinical practice. Since 2012, a new generation GLP-1 agent, exenatide once weekly (QW), has been available for patients with T2DM in the USA, but not as yet in the People’s Republic of China. Previous data indicate that exenatide QW achieves better fasting glucose reductions than sitagliptin or exenatide twice daily, whilst appearing non-inferior to pioglitazone and achieving less reductions than insulin glargine. Exenatide QW was better at improving average postprandial glucose than sitagliptin or titrated insulin glargine, but was inferior to exenatide twice daily. Additionally exenatide QW has a better effect in terms of weight loss than other glycemic medications. Exenatide QW can also reduce blood lipids and lower blood pressure. Accordingly, exenatide QW is cost-effective, achieves good clinical outcomes, and has acceptable side effects, indicating that it has promising prospects for future use in the People’s Republic of China.

Novel 4-heteroaryl-antipyrines as DPP-IV inhibitors

Type 2 diabetes mellitus is a vast growing progressive disease that almost affects one person among every twelve globally. Regardless the availability of wide variety of oral hypoglycemics, only one-third of patients achieves proper glycemic control. With the advantage of the low risk of hypoglycemia, DPP-IV attracted the attention of medicinal chemists as a new target for oral hypoglycemics. In this report, a lead compound 1, with antipyrine scaffold, was obtained, and its binding mode was calculated. Several derivatives with bridged nitrogenous heterocycles have been synthesized via multicomponent reaction under controlled microwave heating conditions. The antidiabetic activity versus DPP-IV protein was evaluated and compared with sitagliptin. Compounds with smaller- or medium-sized nitrogenous bridges were comparable with sitagliptin in terms of DPP-IV inhibitory activity, potentially via targeting Glu203 and Glu204. The oral hypoglycemic activities of compounds with submicromolar IC50 values were further evaluated using diabetic mouse model.