Inhibition of DPP-4: a new therapeutic approach for the treatment of type 2 diabetes

Comprehensive safety profile of dipeptidyl peptidase-4 inhibitors: a post-marketing study based on FAERS database using signal detection algorithms

BACKGROUND

Dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) have acquired a foothold in managing type 2 diabetes mellitus, but few concerns have arisen regarding their overall safety profile. The aim of this study is to assess the potential risk of DPP-4 inhibitors by analyzing data from the FDA Adverse Event Reporting System (FAERS) database.

RESEARCH DESIGN AND METHODS

This is a retrospective study which explored the FAERS database till March 2023 for the collection of safety reports. The disproportionality analysis was performed using signal detection algorithms (SDAs) incorporating frequentist-based data mining approach such as relative reporting ratio (RRR), reporting odds ratio (ROR) and proportional reporting ratio (PRR) with 95% confidence interval (CI).

RESULTS

A total of 14,573 adverse event reports were reported in the FAERS public dashboard associated with all the included DPP-4 inhibitors. The computed PRR, ROR, and RRR indicated positive signals for DPP-4 inhibitors with cardiac failure, pancreatitis, pemphigoid, hypoglycemia, acute kidney injury and lactic acidosis. Saxagliptin showed a higher signal score for cardiac failure, while sitagliptin was more associated with pancreatitis. Moreover, alogliptin exhibited an elevated signal score associated with pancreatic carcinoma.

CONCLUSION

Several significant disproportionality signals were observed with DPP-4 inhibitors. However, clinicians have to consider the comorbidities and concomitant drugs while prescribing these drugs.

GLP-1/GIP Agonist as an Intriguing and Ultimate Remedy for Combating Alzheimer's Disease through its Supporting DPP4 Inhibitors: A Review

BACKGROUND

Alzheimer's disease (AD) is a widespread neurological illness in the elderly, which impacted about 50 million people globally in 2020. Type 2 diabetes has been identified as a risk factor. Insulin and incretins are substances that have various impacts on neurodegenerative processes. Preclinical research has shown that GLP-1 receptor agonists decrease neuroinflammation, tau phosphorylation, amyloid deposition, synaptic function, and memory formation. Phase 2 and 3 studies are now occurring in Alzheimer's disease populations. In this article, we present a detailed assessment of the therapeutic potential of GLP-1 analogues and DPP4 inhibitors in Alzheimer's disease.

AIM

This study aimed to gain insight into how GLP-1 analogues and associated antagonists of DPP4 safeguard against AD.

METHODS

This study uses terms from search engines, such as Scopus, PubMed, and Google Scholar, to explore the role, function, and treatment options of the GLP-1 analogue for AD.

RESULTS

The review suggested that GLP-1 analogues may be useful for treating AD because they have been linked to anti-inflammatory, neurotrophic, and neuroprotective characteristics. Throughout this review, we discuss the underlying causes of AD and how GLP signaling functions.

CONCLUSION

With a focus on AD, the molecular and pharmacological effects of a few GLP-1/GIP analogs, both synthetic and natural, as well as DPP4 inhibitors, have been mentioned, which are in the preclinical and clinical studies. This has been demonstrated to improve cognitive function in Alzheimer's patients.

Efficacy of Bee Products (Anzer Honey, Pollen and Propolis) in Detection and Healing of Damage Induced by Antidiabetic Drug Vildagliptin/Metformin Hydrochloride in Healthy Human Pancreatic Cells: Cytotoxic, Genotoxic and Biochemical Studies

BACKGROUND AND OBJECTIVE

Although drugs are powerful therapeutic agents, they have a range of side effects. These side effects are sometimes cellular and not clinically noticeable. Vildagliptin/metformin hydrochloride is one of the most widely used oral antidiabetic drugs with two active ingredients. In this study, we investigated its harmful effects on the metabolic activation system in healthy human pancreatic cells "hTERT-HPNE", and we aimed to improve these harmful effects by natural products. To benefit from the healing effect, we used the unique natural products produced by the bees of the Anzer Plateau in the Eastern Black Sea Region of Turkey.

METHODS

Cytotoxic and genotoxic effects of the drug were investigated by different tests, such as MTT, flow cytometry-apoptosis and comet assays. Anzer honey, pollen and propolis were analyzed by gas chromatography/mass spectrometry (G/C-MS). A total of 19 compounds were detected, constituting 99.9% of the samples.

RESULTS

The decrease in cell viability at all drug concentrations was statistically significant compared to the negative control (P<0.05). A statistically significant decrease was detected in the apoptosis caused by vildagliptin/metformin hydrochloride with the supplementation of Anzer honey, pollen and propolis in hTERT-HPNE cells (P<0.05).

CONCLUSION

This study can contribute to other studies testing the healing properties of natural products against the side effects of oral antidiabetics in human cells. In particular, Anzer honey, pollen and propolis can be used as additional foods to maintain cell viability and improve heal damage and can be evaluated against side effects in other drug studies.

Efficacy and safety of cetagliptin as monotherapy in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled phase 3 trial

AIM

To assess the efficacy and safety of the dipeptidyl peptidase-4 inhibitor, cetagliptin, as monotherapy in Chinese patients with type 2 diabetes (T2D) and inadequate glycaemic control.

MATERIALS AND METHODS

In total, 504 eligible patients with T2D were enrolled and randomized to cetagliptin 50 mg once daily, cetagliptin 100 mg once daily or placebo at a ratio of 2:2:1 for 24 weeks of double-blind treatment, then all patients received cetagliptin 100 mg once daily for 28 weeks of open-label treatment. The primary efficacy endpoint was the change in HbA1c level from baseline at week 24.

RESULTS

After 24 weeks, HbA1c from baseline was significantly reduced with cetagliptin 50 mg (-1.08%) and cetagliptin 100 mg (-1.07%) compared with placebo (-0.35%). The placebo-subtracted HbA1c reduction was -0.72% with cetagliptin 50 mg and 100 mg. Patients with a baseline HbA1c of 8.5% or higher had a greater HbA1c reduction with cetagliptin than those patients with a baseline HbA1c of less than 8.5%. Both doses studied led to a significantly higher proportion of patients (42.3% with 100 mg and 45.0% with 50 mg) achieving an HbA1c of less than 7.0% compared with placebo (12.9%). Cetagliptin also significantly lowered fasting plasma glucose and 2-hour postmeal plasma glucose relative to placebo. The incidence of adverse experiences was similar between cetagliptin and placebo. No drug-related hypoglycaemia was reported.

CONCLUSIONS

Cetagliptin monotherapy was effective and well tolerated in Chinese patients with T2D who had inadequate glycaemic control on exercise and diet.

Whey protein hydrolysates improve high-fat-diet-induced obesity by modulating the brain-peripheral axis of GLP-1 through inhibition of DPP-4 function in mice

PURPOSE

Obesity is a growing global health concern. Recent literature indicates a prominent role of glucagon-like peptide-1 (GLP-1) in glucose metabolism and food intake. The synergistic action of GLP-1 in the gut and brain is responsible for its satiety-inducing effect, suggesting that upregulation of active GLP-1 levels could be an alternative strategy to combat obesity. Dipeptidyl peptidase-4 (DPP-4) is an exopeptidase known to inactivate GLP-1, suggesting that its inhibition could be a crucial strategy for effectively extending the half-life of endogenous GLP-1. Peptides derived from partial hydrolysis of dietary proteins are gaining traction due to their inhibitory activity on DPP-4.

METHODS

Whey protein hydrolysate from bovine milk (bmWPH) was produced using simulated in situ digestion, purified using RP-HPLC, and characterized for DPP-4 inhibition. The antiadipogenic and antiobesity activity of bmWPH was then studied in 3T3-L1 preadipocytes and high-fat diet-induced obesity (HFD) mice model, respectively.

RESULTS

The dose-dependent inhibitory effect of bmWPH on the catalytic activity of DPP-4 was observed. Additionally, bmWPH suppressed adipogenic transcription factors and DPP-4 protein levels, leading to a negative effect on preadipocyte differentiation. In an HFD mice model, co-administration of WPH for 20 weeks downregulated adipogenic transcription factors, resulting in a concomitant reduction in whole body weight and adipose tissues. Mice fed with bmWPH also showed a marked reduction in DPP-4 levels in WAT, liver, and serum. Furthermore, HFD mice fed with bmWPH exhibited increased serum and brain GLP levels, which led to a significant decrease in food intake.

CONCLUSION

In conclusion, bmWPH reduces body weight in HFD mice by suppressing appetite through GLP-1, a satiety-inducing hormone, in both the brain and peripheral circulation. This effect is achieved through modulation of both the catalytic and non-catalytic activity of DPP-4.

Applications of synthetic biology in medical and pharmaceutical fields

Synthetic biology aims to design or assemble existing bioparts or bio-components for useful bioproperties. During the past decades, progresses have been made to build delicate biocircuits, standardized biological building blocks and to develop various genomic/metabolic engineering tools and approaches. Medical and pharmaceutical demands have also pushed the development of synthetic biology, including integration of heterologous pathways into designer cells to efficiently produce medical agents, enhanced yields of natural products in cell growth media to equal or higher than that of the extracts from plants or fungi, constructions of novel genetic circuits for tumor targeting, controllable releases of therapeutic agents in response to specific biomarkers to fight diseases such as diabetes and cancers. Besides, new strategies are developed to treat complex immune diseases, infectious diseases and metabolic disorders that are hard to cure via traditional approaches. In general, synthetic biology brings new capabilities to medical and pharmaceutical researches. This review summarizes the timeline of synthetic biology developments, the past and present of synthetic biology for microbial productions of pharmaceutics, engineered cells equipped with synthetic DNA circuits for diagnosis and therapies, live and auto-assemblied biomaterials for medical treatments, cell-free synthetic biology in medical and pharmaceutical fields, and DNA engineering approaches with potentials for biomedical applications.

Analysis of Antidiabetic Activity of Squalene via In Silico and In Vivo Assay

Squalene has been tested widely in pharmacological activity including anticancer, antiinflammatory, antioxidant, and antidiabetic properties. This study aims to examine antidiabetic activity of squalene in silico and in vivo models. In the in silico model, the PASS server was used to evaluate squalene antidiabetic properties. Meanwhile, the in vivo model was conducted on a Type 2 Diabetes Mellitus (T2DM) with the rats separated into three groups. These include squalene (160 mg/kgbw), metformin (45 mg/kgbw), and diabetic control (DC) (aquades 10 mL/kgbw) administered once daily for 14 days. Fasting Blood Glucose Level (FBGL), Dipeptidyl Peptidase IV (DPPIV), leptin, and Superoxide Dismutase (SOD) activity were measured to analysis antidiabetic and antioxidant activity. Additionally, the pancreas was analysed through histopathology to examine the islet cell. The results showed that in silico analysis supported squalene antidiabetic potential. In vivo experiment demonstrated that squalene decreased FBGL levels to 134.40 ± 16.95 mg/dL. The highest DPPIV level was in diabetic control- (61.26 ± 15.06 ng/mL), while squalene group showed the lowest level (44.09 ± 5.29 ng/mL). Both metformin and squalene groups showed minor pancreatic rupture on histopathology. Leptin levels were significantly higher (p < 0.05) in diabetic control group (15.39 ± 1.77 ng/mL) than both squalene- (13.86 ± 0.47 ng/mL) and metformin-treated groups (9.22 ± 0.84 ng/mL). SOD activity were higher in both squalene- and metformin-treated group, particularly 22.42 ± 0.27 U/mL and 22.81 ± 0.08 U/mL than in diabetic control (21.88 ± 0.97 U/mL). In conclusion, in silico and in vivo experiments provide evidence of squalene antidiabetic and antioxidant properties.

Coumarin-Based Sulfonamide Derivatives as Potential DPP-IV Inhibitors: Pre-ADME Analysis, Toxicity Profile, Computational Analysis, and In Vitro Enzyme Assay

Recent research on dipeptidyl peptidase-IV (DPP-IV) inhibitors has made it feasible to treat type 2 diabetes mellitus (T2DM) with minimal side effects. Therefore, in the present investigation, we aimed to discover and develop some coumarin-based sulphonamides as potential DPP-IV inhibitors in light of the fact that molecular hybridization of many bioactive pharmacophores frequently results in synergistic activity. Each of the proposed derivatives was subjected to an in silico virtual screening, and those that met all of the criteria and had a higher binding affinity with the DPP-IV enzyme were then subjected to wet lab synthesis, followed by an in vitro biological evaluation. The results of the pre-ADME and pre-tox predictions indicated that compounds 6e, 6f, 6h, and 6m to 6q were inferior and violated the most drug-like criteria. It was observed that 6a, 6b, 6c, 6d, 6i, 6j, 6r, 6s, and 6t displayed less binding free energy (PDB ID: 5Y7H) than the reference inhibitor and demonstrated drug-likeness properties, hence being selected for wet lab synthesis and the structures being confirmed by spectral analysis. In the in vitro enzyme assay, the standard drug Sitagliptin had an IC₅₀ of 0.018 µM in the experiment which is the most potent. All the tested compounds also displayed significant inhibition of the DPP-IV enzyme, but 6i and 6j demonstrated 10.98 and 10.14 µM IC₅₀ values, respectively, i.e., the most potent among the synthesized compounds. Based on our findings, we concluded that coumarin-based sulphonamide derivatives have significant DPP-IV binding ability and exhibit optimal enzyme inhibition in an in vitro enzyme assay.

In silico prediction of the possible antidiabetic and anti-inflammatory targets of Nymphaea lotus-derived phytochemicals and mechanistic insights by molecular dynamics simulations

Nymphaea lotus is used traditionally for the treatment of diabetes and its complications. However, the mode of action and the likely bioactive phytochemicals involved are not yet fully explored. GC-MS analysis was employed to identify the inherent compounds in N. lotus leaves. To gain an insight into the antidiabetic mode of action of this plant, the identified phytochemicals were subjected to computational studies against four molecular targets of diabetes, dipeptidyl peptidase-4, glycogen synthase kinase 3, NADPH oxidase (NOX), sodium-glucose co-transporter-2, and one target of inflammation, cyclooxygenase-2. Compounds with notable binding affinity were subjected to druggability test. Results from molecular docking showed that seven of the compounds investigated exhibited druggability properties and had outstanding binding affinity values for these targets relative to values obtained for the respective standards of each of the targets. Analysis of the MD trajectories from a 100 ns atomistic run shows that the integrities of the complex systems were more stable and preserved throughout the simulation than the unbound protein. These results indicated that the antidiabetic and anti-inflammatory effects of these compounds might be via the inhibition of these targets, laying the foundation for further studies, such as in vitro and in vivo studies to fully validate the anti-diabetic agents from this plant.Communicated by Ramaswamy H. Sarma.

Immunotropic effects of hypoglycemic agents on coronavirus infection: a view from the perspective of pharmacogenetics

Diabetes mellitus is a predictor of the severe course of a new coronavirus infection and high mortality, in this regard, the selection of appropriate hypoglycemic therapy is a vital issue. In this article, we paid attention to dipeptidyl peptidase-4 (DPP-4) inhibitors, since this group of drugs has features like low risk of hyperglycemia and immuno-mediated effects. For the most effective treatment, it is necessary to take into account the individual characteristics of each patient, namely, the achievements of pharmacogenetics. The genetic variability of the response to therapy with DPP-4 inhibitors is due to a variety of polymorphisms, several main variations are considered in the review. The ambiguity of the available studies on the effectiveness of DPP-4 inhibitors in patients with type 2 diabetes with COVID-19 indicates the need to continue pharmacogenetic studies. The combination of knowledge about the subtleties of the mechanisms of pharmacological action of drugs and individual characteristics of pharmacodinamics will ensure the greatest effectiveness and safety of personalized therapy of diabetes mellitus against the background of coronavirus infection.

Oxidative stress in the pathophysiology of type 2 diabetes and related complications: Current therapeutics strategies and future perspectives

Type 2 diabetes (T2DM) is a persistent metabolic disorder rising rapidly worldwide. It is characterized by pancreatic insulin resistance and β-cell dysfunction. Hyperglycemia induced reactive oxygen species (ROS) production and oxidative stress are correlated with the pathogenesis and progression of this metabolic disease. To counteract the harmful effects of ROS, endogenous antioxidants of the body or exogenous antioxidants neutralise it and maintain bodily homeostasis. Under hyperglycemic conditions, the imbalance between the cellular antioxidant system and ROS production results in oxidative stress, which subsequently results in the development of diabetes. These ROS are produced in the endoplasmic reticulum, phagocytic cells and peroxisomes, with the mitochondrial electron transport chain (ETC) playing a pivotal role. The exacerbated ROS production can directly cause structural and functional modifications in proteins, lipids and nucleic acids. It also modulates several intracellular signaling pathways that lead to insulin resistance and impairment of β-cell function. In addition, the hyperglycemia-induced ROS production contributes to micro- and macro-vascular diabetic complications. Various in-vivo and in-vitro studies have demonstrated the anti-oxidative effects of natural products and their derived bioactive compounds. However, there is conflicting clinical evidence on the beneficial effects of these antioxidant therapies in diabetes prevention. This review article focused on the multifaceted role of oxidative stress caused by ROS overproduction in diabetes and related complications and possible antioxidative therapeutic strategies targeting ROS in this disease.

Synthesis, Characterization and Screening of Some Novel 2-Methyl-N'- [(Z)-Substituted-Phenyl ethylidene] Imidazo [1, 2-a] Pyridine-3-Carbohy drazide Derivatives as DPP-IV Inhibitors for the Treatment of Type 2 Diabetes Mellitus

Background:

One of the leading global metabolic diseases marked by insulin resistance and chronic hyperglycemia is type 2 diabetes mellitus (T2DM). Since the last decade, DPP-4 enzyme inhibition has proven to be a successful, safe, and well-established therapy for the treatment of T2DM.

Objective:

The present work reports the synthesis, characterization, and screening of some novel 2- methyl-N'-[(Z)-substituted-phenyl ethylidene] imidazo [1, 2-a] pyridine-3-carbohydrazide derivatives as DPP-IV inhibitors for the treatment of T2DM.

Methods:

The molecular docking was performed to study these derivatives' binding mode in the enzyme's allosteric site. All the synthesized compounds were subjected for DPP-IV enzyme assay and in vivo antihyperglycemic activity in STZ-induced diabetic rats.

Results:

The synthesized derivatives exhibited potent antidiabetic activity as compared to the standard drug Sitagliptin. Out of sixteen compounds, A1, A4, B4, C2, C3, and D4 have shown promising antidiabetic activity against the DPP-IV enzyme. The most promising compound, C2, showed a percentage inhibition of 72.02±0.27 at 50 μM concentration. On the 21st-day, compound C2 showed a significant reduction in serum blood glucose level, i.e., 156.16±4.87 mg/dL, then diabetic control, which was 280.00±13.29 mg/dL whereas, standard Sitagliptin showed 133.50±11.80 mg/dL. In the in vivo antihyperglycemic activity, the compounds have exhibited good hypoglycemic potential in fasting blood glucose in the T2DM animal model. All the docked molecules have exhibited perfect binding affinity towards the active pocket of the enzyme. The synthesized derivatives were screened through Lipinski's rule of five for better optimization, and fortunately, none of them violated the rule.

Conclusion:

The above results indicate that compound C2 is a relatively active and selective hit molecule that can be structurally modified to enhance the DPP-IV inhibitor's potency and overall pharmacological profile. From the present work, it has been concluded that substituted pyridine-3-carbohydrazide derivatives possess excellent DPP-IV inhibitory potential and can be better optimized further by generating more in vivo, in vitro models.

Synthesis of 5(S)-Methyl-L-Proline containing Peptidomimetic Compounds and their In-Vitro Evaluation for Dipeptidyl Peptidase-4 Inhibition

Background:

Type 2 diabetes mellitus (T2DM), which is the epidemic of the 21st century, has affected millions of people worldwide. Traditional methods available for the treatment are associated with various side effects. Among the newer therapies, DPP-4 (Dipeptidyl peptidase-4) inhibition has been a promising therapy for the past decade with the scope of further development, especially in peptidomimetics.

Objective:

5(S)-methyl-L-proline containing peptidomimetic compounds were designed in the previous work. The designed compounds were synthesized and characterized by spectral methods, such as mass spectrometry, 1H NMR, and 13C NMR (Nuclear magnetic resonance) spectroscopy. The purity of the final compounds was determined by high-performance liquid chromatography (HPLC). The synthesized compounds were in vitro evaluated for their DPP-4 inhibitory activity.

Method:

Compounds were peptide in nature and were synthesized using the conventional synthesis approach, where peptide synthesis was done using an acid-amine coupling reagent. They were evaluated through fluorimetric enzyme-based assay using a DPP-4 inhibitor screening kit. Moreover, the CLARIOstar microplate reader instrument was used to measure fluorescence.

Results:

5(S)-methyl-L-proline containing 13 compounds were synthesized. All of them were characterized for structural integrity using spectral methods. They had HPLC purity of more than 95% and were evaluated for DPP-4 inhibition. Compounds 001, 007, 010, 011, 014, and 017 were found to have good inhibition than others. These compounds were further evaluated at different concentrations to develop a linear correlation coefficient (R2).

Conclusion:

Six compounds were found to have good DPP-4 inhibition, hence it further opens the possibility of developing DPP-4 inhibitor-containing 5(S)-methyl-L-proline.

A review on phytochemical and pharmacological facets of tropical ethnomedicinal plants as reformed DPP-IV inhibitors to regulate incretin activity

Type 2 diabetes mellitus is a metabolic disorder resulting from impaired insulin secretion and resistance. Dipeptidyl peptidase (DPP)-IV is an enzyme known to trigger the catalysis of insulinotropic hormones, further abating the endogenous insulin levels and elevating the glucose levels in blood plasma. In the field of drug development, DPP-IV inhibitors have opened up numerous opportunities for leveraging this target to generate compounds as hypoglycemic agents by regulating incretin activity and subsequently decreasing blood glucose levels. However, the practice of synthetic drugs is an apparent choice but poses a great pharmacovigilance issue due to their incessant undesirable effects. The ideology was set to inventively look upon different ethnomedicinal plants for their anti-diabetic properties to address these issues. To date, myriads of phytochemicals are characterized, eliciting an anti-diabetic response by targeting various enzymes and augmenting glucose homeostasis. Antioxidants have played a crucial role in alleviating the symptoms of diabetes by scavenging free radicals or treating the underlying causes of metabolic disorders and reducing free radical formation. Plant-based DPP-IV inhibitors, including alkaloids, phenolic acid, flavonoids, quercetin, and coumarin, also possess antioxidant capabilities, providing anti-diabetic and antioxidative protection. This review article provides a new gateway for exploring the ability of plant-based DPP-IV inhibitors to withstand oxidative stress under pathological conditions related to diabetes and for reforming the strategic role of ethnomedicinal plants as potent DPP-IV inhibitors through the development of polyherbal formulations and nanophytomedicines to regulate incretin activity.

Effects of omarigliptin on glucose variability and oxidative stress in type 2 diabetes patients: A prospective study

AIMS

To date, no clinical studies have compared once-weekly dipeptidyl peptidase 4 (DPP-4) inhibitors with once-daily DPP-4 inhibitors in terms of glucose variability (GV) and oxidative stress (OS).

METHODS

Thirty-six patients with type 2 diabetes mellitus (T2DM) treated with once-daily DPP-4 inhibitors for at least 12 weeks were randomized to either continue once-daily DPP-4 inhibitors or receive omarigliptin, a once-weekly DPP-4 inhibitor, for 24 weeks. The primary end points were changes in the diacron-reactive oxygen metabolite (d-ROMs) test, a marker of OS, and GV using flash glucose monitoring. The secondary end point was changes in the diabetes treatment satisfaction questionnaire (DTSQ) scores.

RESULTS

There were no significant group differences in d-ROMs and DTSQ scores after 24 weeks of treatments. However, omarigliptin was superior to once-daily DPP-4 inhibitors in controlling fasting plasma glucose (FPG) and time in range (TIR). Although FPG and TIR were unchanged at 24 weeks after switching to omarigliptin, these parameters increased in the group receiving maintenance therapy with once-daily DPP-4 inhibitors. No statistically significant changes in hemoglobin A1c were observed between the two groups.

CONCLUSIONS

Our findings suggest that switching from once-daily DPP-4 inhibitors to omarigliptin may be efficacious for maintaining FPG and TIR in T2DM patients.

The Involvement of the Mammalian Target of Rapamycin, Protein Tyrosine Phosphatase 1b and Dipeptidase 4 Signaling Pathways in Cancer and Diabetes: A Narrative Review

BACKGROUND

The mammalian target of rapamycin (mTOR), protein tyrosine phosphatase 1b (PTP1B) and dipeptidase 4 (DPP4) signaling pathways regulate eukaryotic cell proliferation and metabolism. Previous researches described different transduction mechanisms in the progression of cancer and diabetes.

METHODOLOGY

We reviewed recent advances in the signal transduction pathways of mTOR, PTP1B and DPP4 regulation and determined the crosstalk and common pathway in diabetes and cancer.

RESULTS

We showed that according to numerous past studies, the proteins participate in the signaling networks for both diseases.

CONCLUSION

There are common pathways and specific proteins involved in diabetes and cancer. This article demonstrates and explains the potential mechanisms of association and future prospects for targeting these proteins in pharmacological studies.

Anti-inflammatory Effects of Empagliflozin and Gemigliptin on LPS-Stimulated Macrophage via the IKK/NF-κB, MKK7/JNK, and JAK2/STAT1 Signalling Pathways

Background

Sodium-glucose cotransporter 2 (SGLT2) and dipeptidyl peptidase-4 (DPP-4) inhibitors are glucose-lowering drugs whose anti-inflammatory properties have recently become useful in tackling metabolic syndromes in chronic inflammatory diseases, including diabetes and obesity. We investigated whether empagliflozin (SGLT2 inhibitor) and gemigliptin (DPP-4 inhibitor) improve inflammatory responses in macrophages, identified signalling pathways responsible for these effects, and studied whether the effects can be augmented with dual empagliflozin and gemigliptin therapy.

Methods

RAW 264.7 macrophages were first stimulated with lipopolysaccharide (LPS), then cotreated with empagliflozin, gemigliptin, or empagliflozin plus gemigliptin. We conducted quantitative RT-PCR (qRT-PCR) to determine the most effective anti-inflammatory doses without cytotoxicity. We performed ELISA and qRT-PCR for inflammatory cytokines and chemokines and flow cytometry for CD80, the M1 macrophage surface marker, to evaluate the anti-inflammatory effects of empagliflozin and gemigliptin. NF-κB, MAPK, and JAK2/STAT signalling pathways were examined via Western blotting to elucidate the molecular mechanisms of anti-inflammation.

Results

LPS-stimulated CD80⁺ M1 macrophages were suppressed by coincubation with empagliflozin, gemigliptin, and empagliflozin plus gemigliptin, respectively. Empagliflozin and gemigliptin (individually and combined) inhibited prostaglandin E₂ (PGE₂) release and COX-2, iNOS gene expression in LPS-stimulated RAW 264.7 macrophages. These three treatments also attenuated the secretion and mRNA expression of proinflammatory cytokines, such as TNF-α, IL-1β, IL-6, and IFN-γ, and proinflammatory chemokines, such as CCL3, CCL4, CCL5, and CXCL10. All of them blocked NF-κB, JNK, and STAT1/3 phosphorylation through IKKα/β, MKK4/7, and JAK2 signalling.

Conclusions

Our study demonstrated the anti-inflammatory effects of empagliflozin and gemigliptin via IKK/NF-κB, MKK7/JNK, and JAK2/STAT1 pathway downregulation in macrophages. In all cases, combined empagliflozin and gemigliptin treatment showed greater anti-inflammatory properties.

Unravelling the involvement of gut microbiota in type 2 diabetes mellitus

Type 2 diabetes mellitus is the most prevalent metabolic disorder characterized by hyperglycemia, hyperlipidemia as well as insulin resistance and is affecting the lives of a huge population across the globe. Genetic mutations, obesity and lack of physical activity constitute the possible factors that can lead to onset and progression of this disorder. However, there is another major factor that can be the root cause of type 2 diabetes mellitus and that is an imbalance in the microorganisms that inhabit the gut. The gut microbiome is a vital component that needs to be given significant attention because any "dysbiosis" in the colonic microorganisms can transform the host from a state of health to a state of disease. This transformation is quite obvious since the gut barrier integrity, host metabolism such as sensitivity to insulin and maintaining blood glucose level are carried out by the tiny organisms inhabiting our intestine. In fact, the normal functioning of the human body is accredited to the microbes, particularly the bacteria, because they generate their metabolites that communicate with host cells and maintain normal physiology. Giving importance to gut health is, therefore, necessary to prevent metabolic diseases that can be maintained by the intake of prebiotics, probiotics, synbiotics along with healthy diet. The tiny microorganisms in the gut that keep our body free of disorders such as type 2 diabetes mellitus need to be in a state of 'eubiosis', else the consequences of disturbance in gut microbes can progress to serious complications in the host.

Evogliptin Suppresses Calcific Aortic Valve Disease by Attenuating Inflammation, Fibrosis, and Calcification

Calcific aortic valve disease (CAVD) accompanies inflammatory cell infiltration, fibrosis, and ultimately calcification of the valve leaflets. We previously demonstrated that dipeptidyl peptidase-4 (DPP-4) is responsible for the progression of aortic valvular calcification in CAVD animal models. As evogliptin, one of the DPP-4 inhibitors displays high specific accumulation in cardiac tissue, we here evaluated its therapeutic potency for attenuating valvular calcification in CAVD animal models. Evogliptin administration markedly reduced calcific deposition accompanied by a reduction in proinflammatory cytokine expression in endothelial nitric oxide synthase-deficient mice in vivo, and significantly ameliorated the mineralization of the primary human valvular interstitial cells (VICs), with a reduction in the mRNA expression of bone-associated and fibrosis-related genes in vitro. In addition, evogliptin ameliorated the rate of change in the transaortic peak velocity and mean pressure gradients in our rabbit model as assessed by echocardiography. Importantly, evogliptin administration in a rabbit model was found to suppress the effects of a high-cholesterol diet and of vitamin D2-driven fibrosis in association with a reduction in macrophage infiltration and calcific deposition in aortic valves. These results have indicated that evogliptin prohibits inflammatory cytokine expression, fibrosis, and calcification in a CAVD animal model, suggesting its potential as a selective therapeutic agent for the inhibition of valvular calcification during CAVD progression.

Maternal sitagliptin treatment attenuates offspring glucose metabolism and intestinal proinflammatory cytokines IL-6 and TNF-α expression in male rats

Increasing evidence shows that maternal overnutrition may increase the risk of diabetes in offspring. We hypothesized that maternal sitagliptin intervention may improve glucose intolerance through gut targeting. Female Sprague-Dawley (SD) rats were fed a normal diet (ND) or a high-fat diet (HFD) for 4 weeks before mating. ND pregnant rats were divided into two subgroups: ND group (ND alone) and the ND-sitagliptin group (ND combined with 10 mg/kg/day sitagliptin treatment). HFD pregnant rats were randomized to one of two groups: HFD group (HFD alone) and the HFD-sitagliptin group (HFD combined with 10 mg/kg/day sitagliptin treatment) during pregnancy and lactation. Glucose metabolism was assessed in offspring at weaning. Intestinal gene expression levels were investigated. Maternal sitagliptin intervention moderated glucose intolerance and insulin resistance in male pups. Moreover, maternal sitagliptin treatment inhibited offspring disordered intestinal expression of proinflammatory markers, including interleukin-6 (Il6), ll1b, and tumor necrosis factor (Tnf), at weaning and reduced intestinal IL-6, TNF-α expression by immunohistochemical staining and serum IL-6, TNF-α levels. However, maternal sitagliptin intervention did not affect offspring serum anti-inflammatory cytokine IL-10 level. Our results are the first to show that maternal sitagliptin intervention moderated glucose metabolism in male offspring. It may be involved with moderating intestinal IL-6 and TNF-α expression in male rat offspring.

Evaluation of the safety of sodium-glucose co-transporter-2 inhibitors for treating patients with type 1 diabetes

AIM

To conduct an overall safety assessment of sodium-glucose co-transporter-2 (SGLT-2) inhibitors used for the treatment of patients with type 1 diabetes (T1D), including ketoacidosis, genital infection, volume depletion, liver and kidney injury events, cardiovascular events, diarrhea and severe hypoglycaemia.

MATERIALS AND METHODS

We searched three databases (Pubmed, Embase and the Cochrane Library) for randomized controlled trials that treated T1D by using SGLT-2 inhibitors from 2000 to 5 March 2020.

RESULTS

Of the 1653 articles identified that fit our search criteria, 22 studies included qualitative-based results, eight of which were randomized clinical trials that included quantitative-based results. Compared with the control group, the SGLT-2 inhibitors treatment group was found to have had an increased incidence of ketoacidosis (P < .00001, OR 4.34, 95% CI [2.37, 7.96], I² = 18%), events leading to discontinuation (P < .0001, OR 1.76, 95% CI [1.34, 2.31], I² = 0%), genital infection (P < .00001, OR 3.64, 95% CI [2.82, 4.70], I² = 0%), volume depletion (P = .006, OR 2.10, 95% CI [1.23, 3.59], I² = 4%) and diarrhoea (P = .008, OR 1.64, 95% CI [1.14, 2.36], I² = 0%). However, according to subgroup analysis, the risk of diarrhoea was dose-related. The incidence of urinary tract infection, cardiovascular events, renal events, liver injury and fracture was not significantly different for the treatment group compared with the control group.

CONCLUSIONS

Despite showing some promise as a treatment approach, the application of SGLT-2 inhibitors for patients with T1D should be considered with caution.

Clinical implications, diagnosis, and management of diabetes in patients with chronic liver diseases

Diabetes mellitus (DM) negatively affects the development and progression of chronic liver diseases (CLD) of various etiologies. Concurrent DM and CLD are also associated with worse clinical outcomes with respect to mortality, the occurrence of hepatic decompensation, and the development of hepatocellular carcinoma (HCC). Unfortunately, early diagnosis and optimal treatment of DM can be challenging, due to the lack of established clinical guidelines as well as the medical complexity of this patient population. We conducted an exploratory review of relevant literature to provide an up-to-date review for internists and hepatologists caring for this patient population. We reviewed the epidemiological and pathophysiological associations between DM and CLD, the impact of insulin resistance on the progression and manifestations of CLD, the pathogenesis of hepatogenic diabetes, as well as the practical challenges in diagnosis and monitoring of DM in this patient population. We also reviewed the latest clinical evidence on various pharmacological antihyperglycemic therapies with an emphasis on liver disease-related clinical outcomes. Finally, we proposed an algorithm for managing DM in patients with CLD and discussed the clinical and research questions that remain to be addressed.

Ligliptin for treatment of type 2 diabetes mellitus with early renal injury: Efficacy and impact on endogenous hydrogen sulfide and endothelial function

BACKGROUND

Diabetes is a clinically common chronic disease, and its incidence has been increasing in recent years. Diabetes is believed to accelerate the process of atherosclerosis in patients, and abnormal endothelial function is an important factor leading to diabetic kidney damage.

AIM

To investigate the efficacy of ligliptin in the treatment of type 2 diabetes mellitus (T2DM) with early renal injury and its effect on serum endogenous hydrogen sulfide (H₂S), endothelial cell particles, and endothelial function.

METHODS

From January 2018 to April 2019, 110 patients with T2DM and early kidney injury treated at our hospital were divided into an observation group (receiving ligliptin treatment, n = 54) and a control group (receiving gliquidone therapy, n = 56). Blood glucose and renal function before and after treatment were compared between the two groups.

RESULTS

The differences in fasting blood glucose, 2 h blood glucose, and glycated hemoglobin were not statistically significant between the two groups after treatment. The urinary albumin excretion rate after treatment in the ligliptin group was 70.32 ± 11.21 µg/min, which was significantly lower than that of the gliquidone group (P = 0.000). Serum endogenous H₂S and endothelial cell microparticles of the ligliptin treatment group were 40.04 ± 8.82 mol/L and 133.40 ± 34.39, respectively, which were significantly lower than those of the gliquidone treatment group (P = 0.000 for both); endothelin-dependent diastolic function and nitric oxide after treatment in the ligliptin group were 7.98% ± 1.22% and 190.78 ± 30.32 mol/L, significantly higher than those of the gliquidone treatment group (P = 0.000 for both).

CONCLUSION

Ligliptin treatment of T2DM with early renal injury has the same glucose-lowering effect as gliquidone treatment. Ligliptin treatment has a better effect and it can significantly improve the renal function and vascular endothelial function of patients, and reduce serum endogenous H₂S and endothelial cell particle levels.

Advances in covalent kinase inhibitors

This comprehensive review details recent advances, challenges and innovations in covalent kinase inhibition within a 10 year period (2007–2018).

Use of Insulin Glargine 100 U/mL for the Treatment of Type 2 Diabetes Mellitus in East Asians: A Review

Insulin glargine (IGlar) 100 U/mL (IGlar-100) is widely used in East Asian countries for the treatment of type 2 diabetes mellitus (T2DM) and is the gold standard of basal insulin treatment. In this review we summarize key information about clinical experience with IGlar-100 in East Asian patients with T2DM, including findings from clinical trials and postmarketing studies. We also provide recommendations and opinions on the optimal use of IGlar-100 in this population. The findings from the studies highlighted in our review indicate that IGlar-100 can be a suitable treatment option for East Asians with T2DM, from initial therapy in combination with oral antihyperglycemic medications through to different combinations and intensification models. FUNDING: Eli Lilly and Company.

Model-based characterization of the relationship between dapagliflozin systemic exposure and HbA1c response in patients with type 1 diabetes mellitus

AIMS

To quantitatively describe the relationship between dapagliflozin systemic exposure and HbA1c response among patients with type 1 diabetes mellitus (T1DM) and assess the potential impact of covariate effects.

MATERIALS AND METHODS

Individual longitudinal HbA1c data from two phase 3 studies in patients with T1DM (24-week treatment with once-daily dapagliflozin 5 or 10 mg or placebo, with adjustable insulin) were analyzed using a non-linear mixed effect modeling approach. Area under the concentration curve was used to measure dapagliflozin systemic exposure. Baseline HbA1c, estimated glomerular filtration rate, reduction in total insulin dose, baseline glucose concentrations, age, sex, race (Asian vs. non-Asian), and insulin administration method (multiple daily injections vs. insulin pump) were assessed as covariates.

RESULTS

A maximum effect (Emax ) model identified a positive exposure-response relationship. Model-predicted placebo-corrected HbA1c reductions after 24 weeks for dapagliflozin 5- and 10-mg doses were - 0.42% [95% confidence interval (CI) -0.47 to -0.36) and - 0.45% (95% CI -0.50 to -0.40), respectively; baseline HbA1c was ~8.4%. This was in good agreement with actual observations from both studies. Baseline HbA1c was a significant covariate: patients with higher baseline HbA1c were predicted to have greater HbA1c reductions.

CONCLUSIONS

The relationship between dapagliflozin systemic exposure and HbA1c response was successfully described in patients with T1DM. None of the tested covariates affected the efficacy of dapagliflozin to a clinically relevant extent. Therefore, no dose adjustment of dapagliflozin is required in patients with T1DM based on the tested covariates. ClinicalTrials.gov, NCT02268214; NCT02460978.

Which is better, high-dose metformin monotherapy or low-dose metformin/linagliptin combination therapy, in improving glycemic variability in type 2 diabetes patients with insufficient glycemic control despite low-dose metformin monotherapy? A randomized, cross-over, continuous glucose monitoring-based pilot study

AIMS/INTRODUCTION

The present study investigated the effect of high-dose metformin or low-dose metformin/linagliptin combination therapy on glycemic variability (GV) in type 2 diabetes patients with insufficient glycemic control despite low-dose metformin monotherapy in a cross-over study using continuous glucose monitoring.

MATERIALS AND METHODS

The present study was carried out with 11 type 2 diabetes outpatients (7% < glycated hemoglobin < 10%) receiving low-dose metformin monotherapy (500-1,000 mg). All patients were assigned to either metformin 1,500 mg monotherapy (HMET) or combination therapy of low-dose (750 mg) metformin and linagliptin 5 mg (LMET + dipeptidyl peptidase-4 [DPP4]). GV was evaluated by continuous glucose monitoring after >4 weeks of the initial treatment and again after cross-over to the other treatment. GV metrics were compared between the treatments using the Wilcoxon signed-rank test.

RESULTS

Of the continuous glucose monitoring-derived GV metrics for the HMET versus LMET + DPP4, mean glucose levels, standard deviations and mean amplitude of glucose excursions were not significantly different. Although the pre-breakfast glucose levels were not significantly different among the treatments (P = 0.248), the 3-h postprandial glucose area under the curve (>160 mg/dL) after breakfast was significantly larger with HMET versus LMET + DPP4 (9,550 [2,075-11,395] vs 4,065 [1,950-8,895]; P = 0.041).

CONCLUSIONS

A comparison of GV with HMET versus LMET + DPP4 suggested that LMET + DPP4 might reduce post-breakfast GV to a greater degree than HMET in type 2 diabetes patients receiving low-dose metformin monotherapy.

Discovery of a Natural-Product-Derived Preclinical Candidate for Once-Weekly Treatment of Type 2 Diabetes

Poor medication adherence is one of the leading causes of suboptimal glycaemic control in approximately half of the patients with type 2 diabetes mellitus (T2DM). Long-acting antidiabetic drugs are clinically needed for improving patients' compliance. Dipeptidyl peptidase-4 (DPP-4) inhibitors play an increasingly important role in the treatment of T2DM because of their favorable properties of weight neutrality and hypoglycemia avoidance. Herein, we report the successful discovery and scale-up synthesis of compound 5, a structurally novel, potent, and long-acting DPP-4 inhibitor for the once-weekly treatment of T2DM. Inhibitor 5 has fast-associating and slow-dissociating binding kinetics profiles as well as slow clearance rate and long terminal half-life pharmacokinetic properties. A single-dose oral administration of 5 (3 mg/kg) inhibited >80% of DPP-4 activity for more than 7 days in diabetic mice. The long-term antidiabetic efficacies of 5 (10 mg/kg, qw) were better than those of the once-weekly trelagliptin and omarigliptin, especially in decreasing the hemoglobin A1c level.

Human DPP9 represses NLRP1 inflammasome and protects against autoinflammatory diseases via both peptidase activity and FIIND domain binding

The inflammasome is a critical molecular complex that activates interleukin-1 driven inflammation in response to pathogen- and danger-associated signals. Germline mutations in the inflammasome sensor NLRP1 cause Mendelian systemic autoimmunity and skin cancer susceptibility, but its endogenous regulation remains less understood. Here we use a proteomics screen to uncover dipeptidyl dipeptidase DPP9 as a novel interacting partner with human NLRP1 and a related inflammasome regulator, CARD8. DPP9 functions as an endogenous inhibitor of NLRP1 inflammasome in diverse primary cell types from human and mice. DPP8/9 inhibition via small molecule drugs and CRISPR/Cas9-mediated genetic deletion specifically activate the human NLRP1 inflammasome, leading to ASC speck formation, pyroptotic cell death, and secretion of cleaved interleukin-1β. Mechanistically, DPP9 interacts with a unique autoproteolytic domain (Function to Find Domain (FIIND)) found in NLRP1 and CARD8. This scaffolding function of DPP9 and its catalytic activity act synergistically to maintain NLRP1 in its inactive state and repress downstream inflammasome activation. We further identified a single patient-derived germline missense mutation in the NLRP1 FIIND domain that abrogates DPP9 binding, leading to inflammasome hyperactivation seen in the Mendelian autoinflammatory disease Autoinflammation with Arthritis and Dyskeratosis. These results unite recent findings on the regulation of murine Nlrp1b by Dpp8/9 and uncover a new regulatory mechanism for the NLRP1 inflammasome in primary human cells. Our results further suggest that DPP9 could be a multifunctional inflammasome regulator involved in human autoinflammatory diseases.

The efficacy and safety of once-weekly DPP-4 inhibitor omarigliptin in patients with type 2 diabetes mellitus: A systemic review and meta-analysis

BACKGROUND

The efficacy and safety of once-weekly dipeptidyl peptidase-4 inhibitor (DPP-4i) omarigliptin as monotherapy or add on to other antihyperglycemic agents (AHAs) in patients with type 2 diabetes mellitus (T2DM) is unclear.

METHODS

PubMed, EMBASE, Cochrane library, and ClinicalTrials.gov were searched from the inception to January 24, 2018. Randomized controlled trials comparing omarigliptin with placebo or other AHAs in T2DM patients were included in our meta-analysis. Risk ratio (RR) and mean difference (MD) were used to evaluate the outcomes.

RESULTS

Totally, 11 trials involving 8276 patients were satisfied with our inclusion criteria. Compared with control group, omarigliptin was associated with a significantly stronger reduction in hemoglobin A1c (HbA1c) (MD 0.38%, 95% confidence interval [CI] [0.18, 0.58], P = .0002) and fasting plasma glucose (MD 0.48 mmol/L, 95% CI [0.14 mmol/L, 0.82 mmol/L], P = .006). Omarigliptin increased the number of participants who achieved HbA1c < 7.0% compared with control group (RR 2.03, 95% CI [1.38, 2.98], P = .0003). No significant difference was found in the aspect of adverse events (RR 1.00, 95% CI [0.97, 1.03], P = .99), serious adverse events (RR 1.02, 95% CI [0.91, 1.13], P = .75), hypoglycemic events (RR 0.86, 95% CI [0.48, 1.54], P = .61) between omarigliptin and control group. Omarigliptin has a homologous efficacy and safety background to other AHAs according to the results of subgroup analysis.

CONCLUSIONS

This review revealed that omarigliptin had a favorable efficacy and safety as monotherapy or add on to other AHAs in treating T2DM patients. It is a superior choice for T2DM patients who have a poor adherence to daily AHAs.

Cross-Talk Between Insulin Signaling and G Protein-Coupled Receptors

Diabetes is a major risk factor for the development of heart failure. One of the hallmarks of diabetes is insulin resistance associated with hyperinsulinemia. The literature shows that insulin and adrenergic signaling is intimately linked to each other; however, whether and how insulin may modulate cardiac adrenergic signaling and cardiac function remains unknown. Notably, recent studies have revealed that insulin receptor and β2 adrenergic receptor (β2AR) forms a membrane complex in animal hearts, bringing together the direct contact between 2 receptor signaling systems, and forming an integrated and dynamic network. Moreover, insulin can drive cardiac adrenergic desensitization via protein kinase A and G protein-receptor kinases phosphorylation of the β2AR, which compromises adrenergic regulation of cardiac contractile function. In this review, we will explore the current state of knowledge linking insulin and G protein-coupled receptor signaling, especially β-adrenergic receptor signaling in the heart, with emphasis on molecular insights regarding its role in diabetic cardiomyopathy.

A randomized, double-blind trial evaluating the efficacy and safety of monotherapy with the once-weekly dipeptidyl peptidase-4 inhibitor omarigliptin in people with type 2 diabetes

AIMS

To assess the efficacy and safety of once-weekly omarigliptin as monotherapy in people with type 2 diabetes mellitus (T2DM).

METHODS

People with T2DM not on glucose-lowering medications, or who were washed off monotherapy or low-dose dual therapy, were randomized double-blind to omarigliptin 25 mg (n=165) or matching omarigliptin placebo (n=164) for 24 weeks, followed by a 30-week period to assess continuing efficacy and safety longer-term of omarigliptin during which metformin was added to the placebo group and metformin placebo to the omarigliptin group.

RESULTS

From a mean baseline HbA1c of 8.0-8.1%, the least squares mean (95% CI) change from baseline in HbA1c at week 24 (primary endpoint) was -0.49% (-0.73, -0.24) in the omarigliptin group and -0.10% (-0.34, 0.14) in the placebo group, for a between-group difference of -0.39% (-0.59, -0.19) (p<.001). Protocol deviation in use of metformin by 38 of 252 (15%) people whose samples were available for evaluation probably attenuated glycemic efficacy results, as suggested by the LS mean difference -0.53% (-0.75, -0.32) after censoring of such participants. At 24 and 54 weeks, the incidences of adverse events (AEs) were similar in the omarigliptin and placebo groups. During 54 weeks there were no AEs of symptomatic hypoglycemia in the omarigliptin group and 5 AEs in the placebo group. Over 54 weeks, a majority of the omarigliptin treatment had a persistent reduction in HbA1c, remaining rescue-free.

CONCLUSIONS

In people with T2DM, omarigliptin monotherapy improved glycemic control over 54 weeks and was generally well tolerated with a low risk of hypoglycemia. ClinicalTrials.gov Identifier: NCT01717313. EudraCT Number: 2012-003626-24.

The effects of dipeptidyl peptidase-4 inhibitors on bone fracture among patients with type 2 diabetes mellitus: A network meta-analysis of randomized controlled trials

Aim

The association between dipeptidyl peptidase-4 inhibitors (DPP-4is), a class of anti-diabetes, and bone fracture in patients with type 2 diabetes mellitus (T2DM) is unknown. This meta-analysis aimed to systematically evaluate the effects of DPP-4is on bone fracture in T2DM patients.

Methods

We searched the Cochrane Library, Embase, Medline and ClinicalTrials.gov from inception through April 28th, 2016 to identify randomized controlled trials (RCTs) that compared DPP-4is with placebo or other anti-diabetes in T2DM patients. RCTs lasting more than 12 weeks and having data on bone fracture were included. We conducted random-effects meta-analysis to estimate odds ratios (ORs) and their 95% confidence intervals (CIs), and network meta-analysis (NMA) to supplement direct comparisons. Predictive interval plot and node-splitting method were used to evaluate the heterogeneity and inconsistency for NMA, while the funnel plot was applied to explore publication bias. Besides, study quality was assessed according to Cochrane risk of bias tool.

Results

We identified 75 RCTs with a total of 70,207 patients and 11 treatments: interventions included 5 DPP-4is (alogliptin, linagliptin, saxagliptin, sitagliptin, vildagliptin), while controls included placebo and 5 other anti-diabetes (sulfonylureas, glucagon-like peptide-1 receptor agonists, metformin, thiazolidinediones, sodium-glucose co-transporter 2 inhibitors). In the NMA, the risk of fracture for alogliptin tended to decrease when versus placebo (OR, 0.51; 95% CI, 0.29 to 0.88). Besides, aloglitpin had a lower risk compared with linagliptin (OR, 0.45; 95% CI, 0.20 to 0.99) and saxagliption (OR, 0.46; 95%CI, 0.25 to 0.84); the risk was higher with saxagliptin when versus sitagliptin (OR, 1.90; 95% CI, 1.04 to 3.47) and sulfonylureas (OR, 1.98; 95% CI, 1.06 to 3.71). In the direct pairwise meta-analysis, alogliptin was associated with a non-significant tendency to reduction of bone fracture compared with placebo (OR, 0.54; 95% CI, 0.29 to 1.01). Ranking probability analysis indicated alogliptin decreased the risk of bone fracture most with a probability of 76.3%.

Conclusion

Alogliptin may be associated with a lower risk of bone fracture compared with placebo, linagliptin, or saxagliptin, while other anti-diabetes did not seem to have an association with the risk of bone fracture.

A randomized, placebo-controlled clinical trial evaluating the safety and efficacy of the once-weekly DPP-4 inhibitor omarigliptin in patients with type 2 diabetes mellitus inadequately controlled by glimepiride and metformin

BACKGROUND

Type 2 diabetes (T2D) is a progressive disease that often requires a patient to use multiple antihyperglycemic agents to achieve glycemic control with disease progression. Omarigliptin is a once-weekly dipeptidyl peptidase-4 inhibitor. The purpose of this trial was to assess the efficacy and safety of adding omarigliptin to the treatment regimen of patients with T2D inadequately controlled by dual therapy with metformin and glimepiride.

METHODS

Patients with T2D and HbA1c ≥7.5% and ≤10.5% while on metformin (≥1500 mg/day) and glimepiride (≥4 mg/day) were randomized to omarigliptin 25 mg once-weekly (N = 154) or placebo (N = 153) for 24 weeks. The primary objective was to assess whether omarigliptin was superior to placebo in reducing HbA1c at Week 24. Secondary objectives were to assess the effects of omarigliptin vs. placebo on FPG and the proportion of subjects attaining HbA1c goals of <7% and <6.5%.

RESULTS

From a mean baseline HbA1c of 8.5% (omarigliptin) and 8.6% (placebo), the least squares (LS) mean change from baseline in HbA1c at Week 24 was -0.67% in the omarigliptin group and -0.06% in the placebo group, with a between-group difference (95% CI) of -0.61% (-0.85, -0.38). Treatment with omarigliptin resulted in a significantly greater reduction in FPG relative to placebo (LS mean difference [95% CI] -0.9 mmol/L [-1.4, -0.4]; p < 0.001). The proportion of patients achieving glycemic goals of <7.0% and <6.5% was higher in the omarigliptin group relative to the placebo group. The overall incidences of adverse events (AEs), serious AEs, drug-related AEs and discontinuations were generally similar between treatment groups. The incidence of symptomatic hypoglycemia was 10.5% in the omarigliptin group and 8.5% in the placebo group. Relative to baseline, omarigliptin and placebo treatments were associated with LS mean changes in body weight of -0.1 kg and -0.9 kg, respectively.

CONCLUSION

In patients with T2D and inadequate glycemic control on dual therapy with metformin and glimepiride, compared with placebo, once-weekly omarigliptin provided greater improvement in glycemic control and was generally well tolerated.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01704261 , EudraCT Number: 2012-002612-10. Trial Registration Date: October 8, 2012.

A randomized, placebo- and sitagliptin-controlled trial of the safety and efficacy of omarigliptin, a once-weekly dipeptidyl peptidase-4 inhibitor, in Japanese patients with type 2 diabetes

AIMS

To assess the safety and efficacy of omarigliptin in Japanese patients with type 2 diabetes (T2D).

METHODS

In a 24-week double-blind trial, 414 patients with T2D were randomized to omarigliptin 25 mg once weekly, sitagliptin 50 mg once daily or placebo. The double-blind period was followed by a 28-week open-label extension during which all patients received omarigliptin 25 mg once weekly. Efficacy endpoints were glycated haemoglobin (HbA1c), 2-hour postprandial glucose (PPG) and fasting plasma glucose (FPG) levels.

RESULTS

After 24 weeks, the least squares (LS) mean change from baseline in HbA1c was -0.66% for omarigliptin, -0.65% for sitagliptin and 0.13% for placebo. The difference in LS mean for omarigliptin vs placebo was -0.80% ( P  < .001). The difference in LS mean for omarigliptin vs sitagliptin was -0.02% (95% confidence interval -0.15, 0.12), which met the criterion for non-inferiority to sitagliptin. Both active treatments provided significant reductions in FPG and 2-hour PPG compared with placebo (P < .001). Over the 24-week double-blind period, there were no clinically meaningful differences in the incidence rates of adverse events among the treatment groups. There was 1 episode of symptomatic hypoglycaemia in the sitagliptin group and none in the omarigliptin or placebo groups. In the 28-week open-label period, omarigliptin provided persistent improvements in glycaemic control without notable change in safety profile compared with the double-blind period. Omarigliptin had no meaningful effect on body weight.

CONCLUSIONS

In Japanese patients with T2D, omarigliptin 25 mg once weekly provided significant glucose-lowering compared with placebo and was non-inferior to sitagliptin 50 mg once daily. Omarigliptin was generally well tolerated for up to 52 weeks.

Anti-diabetic potential of peptides: Future prospects as therapeutic agents

Diabetes mellitus is a metabolic disorder in which the glucose level in blood exceeds beyond the normal level. Persistent hyperglycemia leads to diabetes late complication and obviously account for a large number of morbidity and mortality worldwide. Numerous therapeutic options are available for the treatment of diabetes including insulin for type I and oral tablets for type II, but its effective management is still a dream. To date, several options are under investigation in various research laboratories for efficacious and safer agents. Of them, peptides are currently amongst the most widely investigated potential therapeutic agents whose design and optimal uses are under development. A number of natural and synthetic peptides have so far been found with outstanding antidiabetic effect mediated through diverse mechanisms. The applications of new emerging techniques and drug delivery systems further offer opportunities to achieve the desired target outcomes. Some outstanding peptides in preclinical and clinical studies with better efficacy and safety profile have already been identified. Further detail studies on these peptides may therefore lead to significant clinically useful antidiabetic agents.

A randomized, double-blind, non-inferiority trial evaluating the efficacy and safety of omarigliptin, a once-weekly DPP-4 inhibitor, or glimepiride in patients with type 2 diabetes inadequately controlled on metformin monotherapy

OBJECTIVE

To evaluate the efficacy and safety of adding the once-weekly DPP-4 inhibitor omarigliptin or the sulfonylurea glimepiride to the treatment regimen of patients with type 2 diabetes (T2DM) and inadequate glycemic control on metformin monotherapy.

METHODS

Patients with T2DM and HbA1c ≥6.5% to ≤9.0% while on a stable dose of metformin (≥1500 mg/day) were randomized to omarigliptin 25 mg once-weekly (n = 376) or glimepiride up to 6 mg once daily (n = 375) for 54 weeks. The primary hypothesis was that omarigliptin is non-inferior to glimepiride in reducing HbA1c at week 54.

RESULTS

The mean baseline HbA1c was 7.5% in the omarigliptin group and 7.4% in the glimepiride group. After 54 weeks, the least squares (LS) mean change from baseline in HbA1c was -0.30% in the omarigliptin group and -0.48% in the glimepiride group, with a between-group difference (95% CI) of 0.18% (0.06, 0.30), which met the pre-specified criterion for declaring non-inferiority. The incidence of symptomatic hypoglycemia was 5.3% in the omarigliptin group and 26.7% in the glimepiride group. With the exception of hypoglycemia, the incidences of adverse events and discontinuations were similar between treatment groups. Relative to baseline, omarigliptin was associated with a mean weight loss (-0.4 kg) and glimepiride a mean weight gain (+1.5 kg).

CONCLUSIONS

After 54 weeks, as add-on therapy to metformin, once-weekly omarigliptin was generally well tolerated and non-inferior to glimepiride in improving glycemic control, with a lower incidence of hypoglycemia and with weight loss vs weight gain.

Sitagliptin attenuates high glucose-induced alterations in migration, proliferation, calcification and apoptosis of vascular smooth muscle cells through ERK1/2 signal pathway

Background/Aims

This study investigated the effects of sitagliptin on migration, proliferation, calcification and apoptosis of vascular smooth muscle cells (VSMCs) under high glucose (HG) conditions.

Methods

VSMCs were isolated from the thoracic aorta of Sprague Dawley rats. The cultured VSMCs were subjected to control medium, mannitol medium, HG medium (25 mM), pretreatment with 200 nM sitagliptin in control or HG medium, or the ERK1/2 inhibitor PD98059 in HG medium. Cell proliferation, migration, apoptosis and calcification were determined.

Results

HG conditions promoted the proliferation, migration, calcification and impairment of apoptosis in VSMCs compared with controls (P<0.05). Pretreatment with sitagliptin effectively attenuated proliferation, migration, calcification of cells and increased apoptosis of HG-cultured VSMCs as compared with the HG group (P<0.05). Culture with HG resulted in the up-regulation of p-ERK1/2 in VSMCs, whereas sitagliptin pretreatment could inhibit HG-induced p-ERK1/2 expression. In addition, the ERK1/2 inhibitor PD98059, inhibited proliferation, migration, calcification and promoted the apoptosis of HG-cultured VSMCs compared with the HG group (P<0.05).

Conclusion

The effects of sitagliptin on VSMC under high glucose condition were achieved through ERK1/2 signaling pathways.

A Randomized, Placebo-Controlled Trial Evaluating the Safety and Efficacy of Adding Omarigliptin to Antihyperglycemic Therapies in Japanese Patients with Type 2 Diabetes and Inadequate Glycemic Control

INTRODUCTION

Daily dipeptidyl peptidase-4 (DPP-4) inhibitors are commonly used with other orally administered antihyperglycemic agents (AHA), as combination therapy, to treat Japanese patients with type 2 diabetes. When combination therapy is indicated, use of a once-weekly (q.w.) orally administered DPP-4 inhibitor might be an appropriate therapeutic option for some patients.

METHODS

A 52-week trial was conducted to assess the safety and tolerability (primary objectives) and glycemic efficacy (secondary objectives) of the q.w. DPP-4 inhibitor omarigliptin as add-on therapy to five different classes of orally administered AHA [sulfonylurea (SU), glinide (GL), biguanide (BG), thiazolidinedione (TZD), or α-glucosidase inhibitor (AGI)] commonly used in Japan and having different mechanisms of drug action from DPP-4 inhibitors. The trial consisted of an initial 24-week double-blind, placebo-controlled period during which patients (stratified by background AHA) were randomized to omarigliptin 25 mg q.w. or placebo, followed by a 28-week open-label period during which patients on placebo were switched to omarigliptin.

RESULTS

After 24 weeks, the percentages of patients with adverse events (AEs), serious AEs, drug-related AEs, AEs of symptomatic hypoglycemia, or who discontinued from trial medication because of an AE were generally similar in the omarigliptin and placebo groups, in all background AHA strata and in the overall population. From a mean baseline HbA1c of approximately 8.0%, the placebo-adjusted least-squares mean changes from baseline ranged from -0.80% (AGI stratum) to -1.16% (TZD stratum); p < 0.001 for all background AHA strata. During the open-label period, no safety signals emerged with longer-term treatment. At week 52, the change from baseline in HbA1c in the omarigliptin/omarigliptin group was similar to that of the placebo/omarigliptin group.

CONCLUSIONS

Addition of once-weekly omarigliptin to AHA therapy with an SU, GL, BG, TZD, or AGI for up to 52 weeks was generally safe and well tolerated, and provided persistent efficacy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT01697592.

FUNDING

MSD K.K., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA.

A randomised, double-blind, trial of the safety and efficacy of omarigliptin (a once-weekly DPP-4 inhibitor) in subjects with type 2 diabetes and renal impairment

AIMS

To assess the safety and efficacy of omarigliptin in subjects with type 2 diabetes mellitus (T2DM) and chronic renal impairment (RI).

METHODS

Patients with T2DM with moderate RI (estimated glomerular filtration rate [eGFR] ≥30 to <60 mL/min/1.73 m2 ) (N=114), severe RI (eGFR <30 mL/min/1.73 m2 ) (N=55) or end-stage renal disease on dialysis (N=44), who were either not on an antihyperglycaemic agent therapy for at least 12 weeks at screening, washed-off of oral antihyperglycaemic agent monotherapy or low-dose dual combination therapy, or on insulin monotherapy, with baseline glycated haemoglobin (HbA1c) of 6.5%-10.0% were randomised to omarigliptin or to placebo for 24 weeks (primary end-point) followed by a 30-week period with subjects on placebo switched to blinded glipizide (if not on insulin).

RESULTS

After 24 weeks, from a mean baseline HbA1c of 8.4% in the omarigliptin group and 8.3% in the placebo group, the least squares mean (95% CI) change from baseline in HbA1c in the overall population (all renal strata combined) was -0.77% (-1.00 to -0.54) in the omarigliptin group and -0.44% (-0.67 to -0.21) in the placebo group; between-group difference of -0.33% (-0.63 to -0.02); P=0.035. After 24 weeks, the incidences of subjects with symptomatic hypoglycaemia, one or more adverse event (AE), drug-related AE, serious AE and discontinuation due to an AE were similar in the omarigliptin and placebo groups.

CONCLUSIONS

In this study in subjects with T2DM and RI, relative to placebo, omarigliptin provided clinically meaningful reductions in HbA1c, had a similar incidence of symptomatic hypoglycaemia and was generally well tolerated.

Sensitive and specific LC-ESI-MS/MS method for determination of ZYDPLA1, a novel long-acting dipeptidyl peptidase 4 inhibitor in rat plasma: An application for toxicokinetic study in rats

A rapid and highly specific assay was developed and validated for the estimation of ZYDPLA1 in rat plasma using liquid chromatography coupled to tandem mass spectrometry with positive electrospray ionization. Method validation comprised of parameters such as specificity, matrix effect, precision, accuracy, recovery, stability, etc. The assay procedure involved a simple protein precipitation of ZYDPLA1 and alprazolam (internal standard) from rat plasma using acetonitrile. Chromatographic separation was achieved with a gradient mobile phase comprising: (A) 0.2% ammonia in purified water; (B) 0.1% formic acid in isopropyl alcohol/methanol (1: 1 v/v); and (C) acetonitrile at a flow rate of 1 mL/min on an ACE-5, C18 (4.6 × 50 mm) column with a run time of 5.5 min. The quantitation of ZYDPLA1 was achieved by the summation of four multiple reaction mode transitions (m/z 399.7 → 383.0, 399.7 → 276.10, 399.7 → 153.20 and 399.7 → 127.20), while that of the internal standard was by a single multiple reaction mode transition (m/z 309.10 → 281.00). The lower limit of quantitation achieved was 0.01 μg/mL and the method showed linearity from 0.01 to 25 μg/mL. The intra- and inter-day precision (%CV) of the quality control samples was within 8.81% and accuracy was ±10% of nominal values. This novel method was applied for evaluation of toxicokinetics of ZYDLA1 in rats.

Dipeptidyl Peptidase-4 Induces Aortic Valve Calcification by Inhibiting Insulin-Like Growth Factor-1 Signaling in Valvular Interstitial Cells

Background:

Calcification of the aortic valve leads to increased leaflet stiffness and consequently to the development of calcific aortic valve disease. However, the underlying molecular and cellular mechanisms of calcification remain unclear. Here, we identified that dipeptidyl peptidase-4 (DPP-4, also known as CD26) increases valvular calcification and promotes calcific aortic valve disease progression.

Methods:

We obtained the aortic valve tissues from humans and murine models (wild-type and endothelial nitric oxide synthase-deficient-mice) and cultured the valvular interstitial cells (VICs) and valvular endothelial cells from the cusps. We induced osteogenic differentiation in the primary cultured VICs and examined the effects of the DPP-4 inhibitor on the osteogenic changes in vitro and aortic valve calcification in endothelial nitric oxide synthase-deficient-mice. We also induced calcific aortic stenosis in male New Zealand rabbits (weight, 2.5–3.0 kg) by a cholesterol-enriched diet+vitamin D2 (25 000 IU, daily). Echocardiography was performed to assess the aortic valve area and the maximal and mean transaortic pressure gradients at baseline and 3-week intervals thereafter. After 12 weeks, we harvested the heart and evaluated the aortic valve tissue using immunohistochemistry.

Results:

We found that nitric oxide depletion in human valvular endothelial cells activates NF-κB in human VICs. Consequently, the NF-κB promotes DPP-4 expression, which then induces the osteogenic differentiation of VICs by limiting autocrine insulin-like growth factor-1 signaling. The inhibition of DPP-4 enzymatic activity blocked the osteogenic changes in VICs in vitro and reduced the aortic valve calcification in vivo in a mouse model. Sitagliptin administration in a rabbit calcific aortic valve disease model led to significant improvements in the rate of change in aortic valve area, transaortic peak velocity, and maximal and mean pressure gradients over 12 weeks. Immunohistochemistry staining confirmed the therapeutic effect of Sitagliptin in terms of reducing the calcium deposits in the rabbit aortic valve cusps. In rabbits receiving Sitagliptin, the plasma insulin-like growth factor-1 levels were significantly increased, in line with DPP-4 inhibition.

Conclusions:

DPP-4-dependent insulin-like growth factor-1 inhibition in VICs contributes to aortic valve calcification, suggesting that DPP-4 could serve as a potential therapeutic target to inhibit calcific aortic valve disease progression.

The Effect of Sitagliptin on Lipid Metabolism of Fatty Liver Mice and Related Mechanisms

Background

In clinics, patients with type 2 diabetes complicated with non-alcoholic fatty liver disease (NAFLD) have been shown to receive significant improvements in blood glucose levels, lipid levels, and liver function after sitagliptin treatment, although the mechanism of drug action remains poorly understood. This study investigated the possible mechanism of sitagliptin on lipid metabolism of NAFLD mice.

Material/Methods

Male C57/BL6 mice were induced for NAFLD via 16 weeks of a high-fat diet, and were treated with 15 mg/kg/day sitagliptin for 16 consecutive weeks. Blood lipid levels were measured and samples were stained with hematoxylin and eosin (H&E) and oil red staining for liver pathology and lipid deposition. Serum levels of fibroblast growth factor (FGF)-9 and FGF-21 were quantified by enzyme-linked immunosorbent assay (ELISA). Peroxisome proliferator-activated receptor (PPAR)-α, and cAMP reactive element binding homolog (CREBH) were measured by Western blotting, while fatty acid synthase and carnitine palmitoyltransferase 1 (CPT1) mRNA levels were assayed by RT-PCR.

Results

Compared to the control group, the NAFLD model mice had liver fatty disease, lower serum FGF-21 and FGF-19 levels, elevated serum lipid levels, depressed PPAR-α, CREBH, and CPT1 expression, and enhanced FAS expression (p<0.05). Sitagliptin treatment depressed blood lipid levels, increased serum FGF-21 and FGF-19 levels, PPAR-α, CREBH, and CPT1 expression, and suppressed FAS expression (p<0.05).

Conclusions

Sitagliptin can protect liver tissue and modulate lipid metabolism in NAFLD mice via elevating FGF-21 and FGF-19, upregulating liver PPAR-α and CREBH levels, and mediating expression levels of key enzymes for lipid metabolism.

Randomized clinical trial comparing the efficacy and safety of treatment with the once-weekly dipeptidyl peptidase-4 (DPP-4) inhibitor omarigliptin or the once-daily DPP-4 inhibitor sitagliptin in patients with type 2 diabetes inadequately controlled on metformin monotherapy

AIM

To compare the efficacy and safety of the once-weekly oral dipeptidyl peptidase-4 (DPP-4) inhibitor omarigliptin or once-daily DPP-4 inhibitor sitagliptin in patients with type 2 diabetes (T2DM) and inadequate glycaemic control on metformin.

MATERIALS AND METHODS

Patients with T2DM with a glycated haemoglobin (HbA1c) concentration ≥6.5% to ≤9.0% while on a stable dose of metformin (≥1500 mg/d) were randomized in a double-blind manner to receive omarigliptin 25 mg once weekly (n = 322) or sitagliptin 100 mg once daily (n = 320). The primary analysis assessed whether omarigliptin was non-inferior to sitagliptin in reducing HbA1c at week 24, based on the criterion of having an upper bound of the 95% confidence interval (CI) about the difference less than the non-inferiority bound of 0.3%.

RESULTS

The mean baseline HbA1c was 7.5% in both groups. After 24 weeks, the least squares (LS) mean change in HbA1c from baseline was -0.47% in the omarigliptin group and -0.43% in the sitagliptin group, with a between-group difference of -0.03% (95% CI -0.15, 0.08). This result met the prespecified criterion for declaring non-inferiority. The LS mean change from baseline in fasting plasma glucose and the percentage of patients with HbA1c <7.0% or <6.5% at week 24 were similar in the two treatment groups. There were no notable differences in adverse events and the incidence of symptomatic hypoglycaemia was low and similar in the groups.

CONCLUSIONS

In patients with T2DM and inadequate glycaemic control on metformin, the addition of omarigliptin 25 mg once weekly or sitagliptin 100 mg once daily led to similar improvements in glycaemic control. Both agents were generally well tolerated with a low incidence of hypoglycaemia.