Effect of DPP-IV Inhibitors on Glycemic Variability in Patients with T2DM: A Systematic Review and Meta-Analysis

Exploring the DPP IV inhibitory potential: molecular docking and dynamic simulations of pyridine-3-carboxylic acid and pyrrolidine-2-carboxylic acid analogs

Diabetes mellitus remains a global challenge, with Type 2 Diabetes Mellitus (T2DM) prevalence increasing from 4% to 6.4% in the past 30 years. Presently oral hypoglycaemic agents like GLP-1 agonists, biguanides, sulphonylureas, glinides, and thiazolidinediones are employed in clinical practice. Very recently, novel targets including Dipeptidyl peptidase IV (DPP IV), PPAR, GIP, FFA1, and melatonin have been in the limelight for the development of novel treatment strategies. The present study focuses on the development of DPP IV inhibitors through computational approaches. DPP IV, also referred to as CD26 (cluster of differentiation 26) or adenosine deaminase complexing protein 2, is a protein that is encoded by the DPP IV gene in humans. This enzyme is involved in the metabolism of incretin hormones such as glucagon-like peptides (GLP-1). DPP IV inhibitors prevent the degradation of GLP-1, glucose-dependent insulinotropic peptide (GIP), thereby controlling the concentration of glucose in the blood. Considering the safety and efficacy of DPP IV inhibitors newer molecules were designed with better binding affinity with the protein as compared to existing Sitagliptin, and Vildagliptin-like drugs. Derivatives of nicotinic acid and proline were designed and studied using molecular docking and dynamic simulations. Docking results demonstrated that the NA-13 molecule possesses potent binding affinity with target protein 6B1E (-38.1498 kcal/mol) as compared to standard Sitagliptin (-33.3187 kcal/mol). MD simulation studies showcased that there are fewer variations of RMSD and RMSF for 6B1E-NA-13, 6B1E-P1, and 6B1E-P7 complexes, suggesting the potential of the designed DPP IV inhibitors in the management of T2DM.

Hyperglycemia-driven signaling bridges between diabetes and cancer

Growing epidemiological evidence indicates an association between obesity, type 2 diabetes, and certain cancers, suggesting the existence of common underlying mechanisms in these diseases. Frequent hyperglycemias in type 2 diabetes promote pro-inflammatory responses and stimulate intracellular metabolic flux which rewires signaling pathways and influences the onset and advancement of different types of cancers. Here, we review the provocative impact of hyperglycemia on a subset of interconnected signalling pathways that regulate (i) cell growth and survival, (ii) metabolism adjustments, (iii) protein function modulation in response to nutrient availability (iv) and cell fate and proliferation and which are driven respectively by PI3K (Phosphoinositide 3-kinase), AMPK (AMP-activated protein kinase), O-GlcNAc (O-linked N-acetylglucosamine) and Wnt/β-catenin. Specifically, we will elaborate on their involvement in glucose metabolism, inflammation, and cell proliferation, highlighting their interplay in the pathogenesis of diabetes and cancer. Furthermore, the influence of antineoplastic and antidiabetic drugs on the unbridled cellular pathways will be examined. This review aims to inspire the next molecular studies to understand how type 2 diabetes may lead to certain cancers. This will contribute to personalized medicine and direct better prevention strategies.

Association of dipeptidyl peptidase-4 inhibitor initiation at glycated haemoglobin <7.5% with reduced major clinical events mediated by low glycated haemoglobin variability

AIM

Therapeutic inertia, hypoglycaemia and poor treatment persistence can lead to glycaemic fluctuation and poor outcomes in type 2 diabetes (T2D). We compared glycated haemoglobin (HbA1c) variability, insulin initiation, severe hypoglycaemia and clinical events in patients with T2D initiated dipeptidyl peptidase-4 inhibitors (DPP4is) at low versus high HbA1c thresholds.

METHODS

Using territory-wide electronic medical records in Hong Kong, we curated a propensity score-matched cohort of patients initiated DPP4i at HbA1c <7.5% versus ≥7.5% in 2007-2019. We expressed the HbA1c variability score (HVS) as a proportion of HbA1c varied by ≥0.5% compared with preceding values. We used the Cox model to compare the risks of insulin initiation and clinical outcomes, adjusted for time-varying variables between the two groups. Mediation analysis estimated the effects of HbA1c variability on outcomes.

RESULTS

Among 6874 insulin-naïve patients who initiated DPP4i, 88.7% were treated with metformin and 79.6% with sulphonylureas at baseline (54.9% men; mean age 65.2 ± 11.4 years). After a median follow-up of 4.6 years, compared with the high-threshold plus high-HVS group (≥50%), the low-threshold plus low-HVS (<50%) group had reduced hazard ratios (95% confidence interval) of insulin initiation (0.35, 0.31-0.40), severe hypoglycaemia (0.38, 0.34-0.44), major adverse cardiovascular endpoints (0.76, 0.66-0.88), heart failure (0.42, 0.36-0.49), end-stage kidney disease (0.65, 0.36-0.49) and mortality (0.45, 0.35-0.57). Reduced HbA1c variability explained 31.1%-81.2% of the effect size of DPP4i initiation at HbA1c <7.5% versus ≥7.5% on outcomes.

CONCLUSIONS

In Chinese patients with T2D, avoiding therapeutic inertia with intensified glycaemic control at HbA1c <7.5% using drugs with low risk of hypoglycaemia and good tolerability, such as DPP4i, delayed insulin treatment, reduced HbA1c variability and improved clinical events.

Comparative Effect of Glucose-Lowering Drugs for Type 2 Diabetes Mellitus on Stroke Prevention: A Systematic Review and Network Meta-Analysis

BACKGRUOUND

There is still a lack of research on which diabetic drugs are more effective in preventing stroke. Our network metaanalysis aimed to compare cerebrovascular benefits among glucose-lowering treatments.

METHODS

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and the ClinicalTrials.gov registry for clinical trials from inception through May 25, 2021. We included both prespecified cerebrovascular outcomes and cerebrovascular events reported as severe adverse events. Subgroup analyses were conducted by stroke subtype, publication type, age of patients, baseline glycosylated hemoglobin (HbA1c), duration of type 2 diabetes mellitus, and cardiovascular risks.

RESULTS

Of 2,861 reports and 1,779 trials screened, 79 randomized controlled trials comprising 206,387 patients fulfilled the inclusion criteria. In the pairwise meta-analysis, the use of glucagon-like peptide-1 (GLP-1) agonist was associated with a lower risk of total stroke compared with placebo (relative risk [RR], -0.17; 95% confidence interval [CI], -0.27 to -0.07). In the network meta- analysis, only the use of sodium-glucose cotransporter-2 (SGLT-2) inhibitor was associated with a reduction of total stroke, compared with placebo (RR, 0.81; 95% CI, 0.67 to 0.98). In the subgroup analyses, the use of SGLT-2 inhibitor and GLP-1 agonist was associated with a lower risk of stroke in those with high HbA1c (≥8.0) and low-risk of cardiovascular disease, respectively.

CONCLUSION

SGLT-2 inhibitors and GLP-1 agonists were shown to be beneficial for stroke prevention in patients with type 2 diabetes mellitus.

A Multicenter, Randomized, Open-Label Study to Compare the Effects of Gemigliptin Add-on or Escalation of Metformin Dose on Glycemic Control and Safety in Patients with Inadequately Controlled Type 2 Diabetes Mellitus Treated with Metformin and SGLT-2 Inhibitors (SO GOOD Study)

Background

We aimed to compare efficacy and safety between gemigliptin add-on and escalation of the metformin dose in patients with inadequately controlled type 2 diabetes mellitus (T2DM) despite treatment with metformin and SGLT2 inhibitors.

Methods

This study was a multicenter, randomized, open-label, active-controlled, parallel-group comparative study. Patients with T2DM uncontrolled on metformin and SGLT2 inhibitors were randomized to receive gemigliptin 50 mg as an add-on (GEM group, n = 37) or escalation of the metformin dose (500 mg, MET group, n = 38) for 24 weeks. The primary endpoint was the change in glycosylated hemoglobin (HbA1c) from baseline to week 24.

Results

At weeks 12 and 24, the reduction in HbA1c levels was significantly greater in the GEM group than in the MET group (GEM vs. MET = -0.64% ± 0.34% vs. -0.36% ± 0.50%, p = 0.009 at week 12; -0.61% ± 0.35% vs. -0.33% ± 0.70%, p = 0.045 at week 24). The proportions of patients who achieved target HbA1c levels of <7.0% at weeks 12 and 24 and <6.5% at week 12 were greater in the GEM group than in the MET group. An index of β-cell function was also significantly improved in the GEM group. The safety profiles were similar between the two groups.

Conclusions

Gemigliptin add-on therapy may be more effective than metformin dose escalation in patients with T2DM insufficiently controlled using metformin and SGLT2 inhibitors, without safety concerns. This trial is registered with CRIS_number: KCT0003520.

Association between Glucose-lowering Treatments and Risk of Diabetic Retinopathy in People with Type 2 Diabetes: A Nationwide Cohort Study

INTRODUCTION

Glycaemic variability is possibly linked to the development of diabetic retinopathy, and newer second-line glucose-lowering treatments in type 2 diabetes might reduce glycaemic variability.

AIM

This study aimed to investigate whether newer second-line glucose-lowering treatments are associated with an alternative risk of developing diabetic retinopathy in people with type 2 diabetes.

METHODS

A nationwide cohort of people with type 2 diabetes on second-line glucose-lowering treatment regimens in 2008-2018 was extracted from the Danish National Patient Registry. Adjusted time to diabetic retinopathy was estimated with a Cox Proportional Hazards model. The model was adjusted for age, sex, diabetes duration, alcohol abuse, treatment start year, education, income, history of late-diabetic complications, history of non-fatal major adverse cardiovascular events, history of chronic kidney disease, and history of hypoglycaemic episodes.

RESULTS

Treatment regimens of metformin + basal insulin (HR: 3.15, 95% CI: 2.42-4.10) and metformin + glucagon-like peptide-1 receptor agonist (GLP-1-RA, HR: 1.46, 95% CI: 1.09-1.96) were associated with an increased risk of diabetic retinopathy compared with metformin + dipeptidyl peptidase-4 inhibitors (DPP-4i). Treatment with metformin + sodium-glucose cotransporter-2 inhibitor (SGLT2i, HR: 0.77, 95% CI: 0.28-2.11) was associated with the numerically lowest risk of diabetic retinopathy compared with all regimens investigated.

CONCLUSION

Findings from this study indicate that basal insulin and GLP-1-RA are suboptimal second- line choices for people with type 2 diabetes at risk of developing diabetic retinopathy. However, many other considerations concerning the choice of second-line glucose-lowering treatment for type 2 diabetes patients should be taken into account.

The Current Place of DPP4 Inhibitors in the Evolving Landscape of Type 2 Diabetes Management: Is It Time to Bid Adieu?

During the last decade, the landscape of type 2 diabetes (T2D) management has been completely transformed, moving from a glucose-centric perspective to a holistic approach that also takes into account weight control and organ protection. Dipeptidyl peptidase-4 inhibitors (DPP4i) are oral agents that have been used for the treatment of T2D for almost 20 years. Although they present an excellent safety profile, including the risk of hypoglycemia, they lack the spectacular cardiorenal benefits and weight-loss effects of the newer antidiabetic agents. This poses the question of whether they still deserve a place in the arsenal of drugs against T2D. In this article, we use a hypothetical case scenario to illustrate possible patient profiles where DPP4i could prove useful in the clinical setting. We discuss the advantages and disadvantages of the category, focusing on glycemic control, weight management, and cardiorenal protection, which are the pillars of modern T2D management, also considering its safety profile and cost-effectiveness. We conclude that in most cases, DPP4i present a more favorable risk-benefit ratio compared to sulfonylureas, which are still widely prescribed throughout the world. We also suggest that future research should clarify the reasons behind the contradictory findings between human and animal studies on cardiorenal effects of the class and identify subgroups of patients who would derive most benefit with DPP4i treatment.

Therapeutic Potentials of Microalgae and Their Bioactive Compounds on Diabetes Mellitus

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia due to impaired insulin secretion, insulin resistance, or both. Oxidative stress and chronic low-grade inflammation play crucial roles in the pathophysiology of diabetes mellitus. There has been a growing interest in applying natural products to improve metabolic derangements without the side effects of anti-diabetic drugs. Microalgae biomass or extract and their bioactive compounds have been applied as nutraceuticals or additives in food products and health supplements. Several studies have demonstrated the therapeutic effects of microalgae and their bioactive compounds in improving insulin sensitivity attributed to their antioxidant, anti-inflammatory, and pancreatic β-cell protective properties. However, a review summarizing the progression in this topic is lacking despite the increasing number of studies reporting their anti-diabetic potential. In this review, we gathered the findings from in vitro, in vivo, and human studies to discuss the effects of microalgae and their bioactive compounds on diabetes mellitus and the mechanisms involved. Additionally, we discuss the limitations and future perspectives of developing microalgae-based compounds as a health supplement for diabetes mellitus. In conclusion, microalgae-based supplementation has the potential to improve diabetes mellitus and be applied in more clinical studies in the future.

A randomized trial on the effect of transcutaneous electrical nerve stimulator on glycemic control in patients with type 2 diabetes

Transcutaneous electrical nerve stimulator (TENS) has been demonstrated to be beneficial in glycemic control in animal models, but its application in humans has not been well studied. We randomly assigned 160 patients with type 2 diabetes on oral antidiabetic drugs 1:1 to the TENS study device (n = 81) and placebo (n = 79). 147 (92%) randomized participants (mean [SD] age 59 [10] years, 92 men [58%], mean [SD] baseline HbA_1c level 8.1% [0.6%]) completed the trial. At week 20, HbA_1c decreased from 8.1% to 7.9% in the TENS group (- 0.2% [95% CI - 0.4% to - 0.1%]) and from 8.1% to 7.8% in the placebo group (- 0.3% [95% CI - 0.5% to - 0.2%]) (P = 0.821). Glycemic variability, measured as mean amplitude of glycemic excursion (MAGE) at week 20 were significantly different in the TENS group vs. the placebo group (66 mg/dL [95% CI 58, 73] vs. 79 mg/dL [95% CI 72, 87]) (P = 0.009). Our study provides the clinical evidence for the first time in humans that TENS does not demonstrate a statistically significant HbA_1c reduction. However, it is a safe complementary therapy to improve MAGE in patients with type 2 diabetes.

Production of enzymatic hydrolysates with in vitro antioxidant, antihypertensive, and antidiabetic properties from proteins derived from Arthrospira platensis

The microalga Arthrospira platensis BEA 005B was produced using 80 m² (9 m³) raceway photobioreactors achieving a biomass productivity of 28.2 g·m^-2·day^-1 when operating the reactors in semi-continuous mode (0.33 day^-1). The produced biomass was rich in proteins (58.1 g·100 g^-1) and carbohydrates (25.6 g·100 g^-1); the content of phycocyanins and allophycocyanins was 115.4 and 36.9 mg·g^-1, respectively. Ultrasounds and high-pressure homogenisation allowed recovering approximately 90% of the initial protein content of the biomass; however, the energetic requirements of the former (∼100 kJ·kg^-1) were significantly lower than those of high-pressure homogenisation (∼200 kJ·kg^-1). An in silico analysis revealed that papain and ficin would allow releasing a large number of bioactive peptides with antioxidant, antihypertensive (ACE-I and renin), and antidiabetic (DPP-IV, α-amylase, and α-glucosidase) properties. Both were assessed in vitro together with Alcalase and pepsin leading to the generation of enzymatic hydrolysates with in vitro bioactivity.

Reporting and methodological quality of systematic reviews of DPP-4 inhibitors for patients with type 2 diabetes mellitus: an evidence-based mapping

AIMS

To evaluate the reporting and methodological quality of relevant systematic reviews (SRs) and meta-analyses (MAs) on Dipeptidyl peptidase-4 inhibitors (DPP-4I) for Type 2 diabetes mellitus (T2DM).

METHODS

Relevant SRs and MAs on T2DM and DPP-4I published between 2017 and November 2021 were retrieved from PubMed, Embase, Cochrane Library, Web of Science, VIP, CNKI, CBM, and WanFang databases. Two independent reviewers performed the search, selection, and data extraction. The reporting and methodological quality of the reviewers was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR 2) tools. The relationship between reporting and methodological quality score was assessed with the Spearman correlation test.

RESULTS

Twenty-one studies involving 151,715 participants were included in the study. This overview showed that DPP-4I was safer and more efficacious than other anti-hyperglycemic drugs (OADs) in treating T2DM. The methodological quality of one SR was low, while the rest were very low. Thus, refinements are needed in the quality of protocol and registration information, a complete search strategy, the summary of the evidence, the listing of excluded studies, assessing the potential impact of risk of bias in RCTs, and discussing the RoB on MA results, and the funding of RCTs need improvement for generating SR. In addition, the reporting and methodological quality scores were moderately correlated (r_S = 0.66, P = 0.001).

CONCLUSIONS

DPP-4I is safer and more efficacious than OADs in treating T2DM. However, the reporting and methodological quality of the related SRs was unsatisfactory. Therefore, PRISMA and AMSTAR 2 analyses should be followed to enhance the overall quality of future SRs.

Tenebrio molitor Proteins-Derived DPP-4 Inhibitory Peptides: Preparation, Identification, and Molecular Binding Mechanism

Inhibition of dipeptidyl peptidase-4 (DPP-4) is an effective way to control blood glucose in diabetic patients. Tenebrio (T.) molitor is an edible insect containing abundant protein. T. molitor protein-derived peptides can suppress the DPP-4 activity. However, the amino acid sequence and binding mechanism of these DPP-4 inhibitory peptides remain unclear. This study used the flavourzyme for T. molitor protein hydrolysis, identified the released peptides with DPP-4 inhibitory effect, and investigated the binding interactions of these peptides with DPP-4. The results showed that flavourzyme efficiently hydrolyzed the T. molitor protein, as demonstrated by the high degree of hydrolysis, disappearance of protein bands in SDS-PAGE, and changes to protein structure. The 4-h flavourzyme hydrolysates showed a good inhibitory effect on DPP-4 (IC₅₀ value of 1.64 mg/mL). The fragment of 1000-3000 Da accounted for 10.39% of the total peptides, but showed the strongest inhibitory effect on DPP-4. The peptides LPDQWDWR and APPDGGFWEWGD were identified from this fraction, and their IC₅₀ values against DPP-4 were 0.15 and 1.03 mg/mL, respectively. Molecular docking showed that these two peptides interacted with the DPP-4 active site via hydrogen bonding, hydrophobic interactions, salt bridge formation, π-cation interactions, and π-π stacking. Our findings indicated that T. molitor protein-derived peptides could be used as natural DPP-4 inhibitors.

Incretins as a Potential Treatment Option for Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a metabolic disease affecting an increasing number of pregnant women around the world. It is not only associated with numerous perinatal complications but also has long-term consequences impacting maternal health and fetal development. To prevent them, it is important to keep glucose levels under control. As much as 15-30% of GDM patients will require treatment with insulin, metformin, or glyburide. With that in mind, it is crucial to keep searching for novel and improved pharmacotherapies. Nowadays, there are ongoing studies investigating the use of other groups of drugs that have proven successful in the treatment of T2DM. Glucagon-like peptide-1 (GLP-1) receptor agonist and dipeptidyl peptidase-4 (DPP-4) inhibitor are among the drugs targeting the incretin system and are currently receiving significant attention. The aim of our review is to demonstrate the potential of these medications in treating GDM and preventing its later complications. It seems that both groups may be successful in the GDM management used alone or as an addition to better-known drugs, including metformin and glyburide. However, more clinical trials are needed to confirm their importance in GDM treatment and to demonstrate effective therapeutic strategies.

Hypoglycemic agents and glycemic variability in individuals with type 2 diabetes: A systematic review and network meta-analysis

While hemoglobin A1c (HbA1c) is commonly used to monitor therapy response in type 2 diabetes (T2D), GV is emerging as an essential additional metric for optimizing glycemic control. Our goal was to learn more about the impact of hypoglycemic agents on HbA1c levels and GV in patients with T2D. A systematic review and network meta-analysis (NMA) of randomized controlled trials were performed to assess the effects of glucagon-like peptide 1 receptor agonists (GLP-1 RAs), sodium-glucose cotransporter (SGLT)-2 inhibitors, dipeptidyl peptidase (DPP)-4 inhibitors, sulfonylurea and thiazolidinediones on Mean Amplitude of Glycemic Excursions (MAGE) and HbA1c. Searches were performed using PubMed and EMBASE. A random-effect model was used in the NMA, and the surface under the cumulative ranking was used to rank comparisons. All studies were checked for quality according to their design and also for heterogeneity before inclusion in this NMA. The highest reduction in MAGE was achieved by GLP-1 RAs (SUCRA 0.83), followed by DPP-4 inhibitors (SUCRA: 0.72), and thiazolidinediones (SUCRA: 0.69). In terms of HbA1c reduction, GLP-1 RAs were the most effective (SUCRA 0.81), followed by DPP-4 inhibitors (SUCRA 0.72) and sulfonylurea (SUCRA 0.65). Our findings indicated that GLP-1 RAs have relatively high efficacy in terms of HbA1c and MAGE reduction when compared with other hypoglycemic agents and can thus have clinical application. Future studies with a larger sample size and appropriate subgroup analyses are warranted to completely understand the glycemic effects of these agents in various patients with T2D. The protocol for this systematic review was registered with the International Prospective Register of Systematic Reviews (CRD42021256363).

Expert Opinion: Optimum Clinical Approach to Combination-Use of SGLT2i + DPP4i in the Indian Diabetes Setting

The Asian-Indian phenotype of type 2 diabetes mellitus is uniquely characterized for cardio-metabolic risk. In the context of implementing patient-centric holistic cardio-metabolic risk management as a priority, the choice of various combinations of antidiabetic agents should be individualized. Combined therapy with two classes of antidiabetic agents, namely, dipeptidyl peptidase 4 inhibitors and sodium-glucose co-transporter-2 inhibitors, target several pathophysiological pathways. The wide-ranging clinical outcomes associated with this combination, including improvement of glycemia and adiposity, reduction of metabolic and vascular risk, safety, and simplicity for sustainable compliance, are extremely relevant to the Asian Indian patient population living with T2DM. In this review we describe the available evidence in detail and present a rational practical guidance for the optimum clinical use of this combination in this patient population.

Relation of glucose variability to vulnerable plaque formation in patients with coronary artery disease

BACKGROUND

Although glucose variability (GV) is reportedly associated with coronary plaque vulnerability, namely lipid-rich plaque, details are not fully understood. The aim of this study was to evaluate relations of GV after discharge to vulnerable plaque formation assessed by near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) in patients with and without diabetes.

METHODS

A total of 40 patients undergoing percutaneous coronary intervention under NIRS-IVUS guidance were included, among whom 13 (33%) had diabetes and 20 (50%) presented with acute myocardial infarction (MI). GV was evaluated by a flush glucose monitoring system, primarily with mean amplitude of glycemic excursion (MAGE). Lipid-rich plaque was assessed by maximum lipid core burden index in 4 mm (maxLCBI_4mm) in the target lesion using NIRS-IVUS.

RESULTS

Mean MAGE and maxLCBI_4mm were 69.7 ± 25.6 mg/dl and 508.0 ± 294.9. Intra-day GV was not significantly associated with maxLCBI_4mm in the entire study population, while MAGE was correlated with maxLCBI_4mm in non-diabetic patients (r = 0.46, p = 0.02). In patients with and without acute MI presentation, no significant relations were found between MAGE and maxLCBI_4mm.

CONCLUSION

GV was associated with lipid core plaque formation, especially in non-diabetic patients.

Old and Novel Therapeutic Approaches in the Management of Hyperglycemia, an Important Risk Factor for Atherosclerosis

Hyperglycemia is considered one of the main risk factors for atherosclerosis, since high glucose levels trigger multiple pathological processes, such as oxidative stress and hyperproduction of pro-inflammatory mediators, leading to endothelial dysfunction. In this context, recently approved drugs, such as glucagon-like-peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2i), could be considered a powerful tool for to reduce glucose concentration and cardiovascular risk. Interestingly, many patients with type 2 diabetes mellitus (T2DM) and insulin resistance have been found to be deficient in vitamin D. Recent studies pointed out the unfavorable prognostic values of T2DM and vitamin D deficiency in patients with cardiac dysfunction, either when considered individually or together, which shed light on the role of vitamin D in general health status. New evidence suggests that SGLT2i could adversely affect the production of vitamin D, thereby increasing the risk of fractures, which are common in patients with T2DM. Therefore, given the biological effects of vitamin D as an anti-inflammatory mediator and a regulator of endothelial function and calcium equilibrium, these new findings should be taken into consideration as well. The aim of this review is to gather the latest advancements regarding the use of antidiabetic and antiplatelet drugs coupled with vitamin D supplementation to control glucose levels, therefore reducing the risk of coronary artery disease (CAD).

Effects of Teneligliptin on HbA1c levels, Continuous Glucose Monitoring-Derived Time in Range and Glycemic Variability in Elderly Patients with T2DM (TEDDY Study)

BACKGROUND

To evaluate the effects of teneligliptin on glycosylated hemoglobin (HbA1c) levels, continuous glucose monitoring (CGM)-derived time in range, and glycemic variability in elderly type 2 diabetes mellitus patients.

METHODS

This randomized, double-blinded, placebo-controlled study was conducted in eight centers in Korea (clinical trial registration number: NCT03508323). Sixty-five participants aged ≥65 years, who were treatment-naïve or had been treated with stable doses of metformin, were randomized at a 1:1 ratio to receive 20 mg of teneligliptin (n=35) or placebo (n=30) for 12 weeks. The main endpoints were the changes in HbA1c levels from baseline to week 12, CGM metrics-derived time in range, and glycemic variability.

RESULTS

After 12 weeks, a significant reduction (by 0.84%) in HbA1c levels was observed in the teneligliptin group compared to that in the placebo group (by 0.08%), with a between-group least squares mean difference of -0.76% (95% confidence interval [CI], -1.08 to -0.44). The coefficient of variation, standard deviation, and mean amplitude of glycemic excursion significantly decreased in participants treated with teneligliptin as compared to those in the placebo group. Teneligliptin treatment significantly decreased the time spent above 180 or 250 mg/dL, respectively, without increasing the time spent below 70 mg/dL. The mean percentage of time for which glucose levels remained in the 70 to 180 mg/dL time in range (TIR70-180) at week 12 was 82.0%±16.0% in the teneligliptin group, and placebo-adjusted change in TIR70-180 from baseline was 13.3% (95% CI, 6.0 to 20.6).

CONCLUSION

Teneligliptin effectively reduced HbA1c levels, time spent above the target range, and glycemic variability, without increasing hypoglycemia in our study population.

Influence of dipeptidyl peptidase-4 inhibitors on glycemic variability in patients with type 2 diabetes: A meta-analysis of randomized controlled trials

OBJECTIVE

The influence of dipeptidyl peptidase-4 (DPP4) inhibitors on glycemic variability compared to other oral antidiabetic drugs (OADs), measured based on the mean amplitude of glycemic excursions (MAGE), has not been comprehensively analyzed. The aim of the study was to perform a meta-analysis to compare the effects of DPP4 inhibitors on MAGE with other OADs in type 2 diabetes mellitus (T2DM) patients without concurrent insulin treatments.

METHODS

The Medline (PubMed), Embase (Ovid), and CENTER (Cochrane Library) databases were searched for relevant randomized controlled trials (RCTs). Study characteristics and outcome data were independently extracted by two authors. A random-effect model was used to combine the results.

RESULTS

Fourteen studies with 855 patients were included. Compared to other OADs, DPP4 inhibitors significantly reduced MAGE (mean difference [MD]: -0.69 mmol/L, 95% confidence interval [CI]: -0.95 to -0.43, P<0.001) with mild heterogeneity (I^{2 =} 28%). Predefined subgroup analyses suggested that DPP4 inhibitors were more effective in reducing MAGE compared to insulin secretagogues (MD: -0.92 mmol/L, P<0.001) and non-secretagogues (MD: -0.43 mmol/L, P=0.02), as well as compared to sulfonylureas (MD: -0.91 mmol/L, P<0.001) and sodium glucose cotransporter 2 inhibitors (MD: -0.67 mmol/L, P=0.03).

CONCLUSIONS

DPP4 inhibitors may significantly reduce glycemic variability compared to other oral anti-diabetic drugs, as evidenced by MAGE in T2DM patients with no concurrent insulin treatment.

SYSTEMATIC REVIEW REGISTRATION

INPLASY, registration number: INPLASY2021120113.

The Effect of DPP4 Inhibitor on Glycemic Variability in Patients with Type 2 Diabetes treated with twice-daily Premixed Human Insulin

Objective

To evaluate the effect of adding DPP4 inhibitor (DPP4-i) on glycemic variability (GV) in patients with type 2 diabetes mellitus (T2DM) treated with premixed human insulin (MHI).

Methodology

We conducted a prospective study in patients with T2DM on twice-daily MHI with or without metformin therapy. Blinded continuous glucose monitoring was performed at baseline and following 6 weeks of Vildagliptin therapy.

Results

Twelve patients with mean (SD) age of 55.8 (13.1) years and duration of disease of 14.0 (6.6) years were recruited. The addition of Vildagliptin significantly reduced GV indices (mmol/L): SD from 2.73 (IQR 2.12-3.66) to 2.11 (1.76-2.55), p=0.015; mean amplitude of glycemic excursions (MAGE) 6.94(2.61) to 5.72 (1.87), p=0.018 and CV 34.05 (8.76) to 28.19 (5.36), p=0.010. In addition, % time in range (3.9-10 mmol/l) improved from 61.17 (20.50) to 79.67 (15.33)%, p=0.001; % time above range reduced from 32.92 (23.99) to 18.50 (15.62)%, p=0.016; with reduction in AUC for hyperglycemia from 1.24 (1.31) to 0.47 (0.71) mmol/day, p=0.015. Hypoglycemic events were infrequent and the reduction in time below range and AUC for hypoglycemia did not reach statistical significance.

Conclusion

The addition of DPP4-I to commonly prescribed twice-daily MHI in patients with T2DM improves GV and warrants further exploration.

Fasting Glucose Variability as a Risk Indicator for End-Stage Kidney Disease in Patients with Diabetes: A Nationwide Population-Based Study

Given the fact that diabetes remains a leading cause of end-stage kidney disease (ESKD), multi-aspect approaches anticipating the risk for ESKD and timely correction are crucial. We investigated whether fasting glucose variability (FGV) could anticipate the development of ESKD and identify the population prone to the harmful effects of GV. We included 777,192 Koreans with diabetes who had undergone health examinations more than three times in 2005-2010. We evaluated the risk of the first diagnosis of ESKD until 2017, according to the quartile of variability independent of the mean (VIM) of FG using multivariate-adjusted Cox proportional hazards analyses. During the 8-year follow-up, a total of 7290 incidents of ESKD were found. Subjects in the FG VIM quartile 4 had a 27% higher risk for ESKD compared to quartile 1, with adjustment for cardiovascular risk factors and the characteristics of diabetes. This effect was more distinct in patients aged < 65 years; those with a long duration of diabetes; the presence of hypertension or dyslipidemia; and prescribed angiotensin-converting enzyme inhibitors, metformin, sulfonylurea, α-glucosidase inhibitors, and insulin. In contrast, the relationship between baseline FG status and ESKD risk showed a U-shaped association. FGV is an independent risk factor for kidney failure regardless of FG.

Glycaemic variabilities: Key questions in pursuit of clarity

After years of intensive investigation, the definition of glycaemic variability remains unclear and the term variability in glucose homoeostasis might be more appropriate covering both short and long-term glycaemic variability. For the latter, we remain in the search of an accurate definition and related targets. Recent work leads us to consider that the within-subject variability of HbA1c calculated from consecutive determinations of HbA1c at regular time-intervals could be the most relevant index for assessing the long-term variability with a threshold value of 5% (%CV = SD of HbA1c/mean HbA1c) to separate stability from lability of HbA1c. Presently, no one can deny that short- and long-term glucose variability should be maintained within their lower ranges to limit the incidence of hypoglycaemia. Usually, therapeutic strategies aimed at reducing post-meal glucose excursions, i.e. the major contributor to daily glucose fluctuations, exert a beneficial effect on the short-term glucose variability. This explains the effectiveness of adjunct therapies with either GLP- receptor agonists or SGLT inhibitors in type 2 diabetes. In type 1 diabetes, the application of a CGM device alone reduces the short-term glycaemic variability. In contrast, sophisticated insulin delivery does not necessarily lead to such reductions despite marked downward shifts of 24-hour glycaemic profiles. Such contrasting observations raise the question as to whether the prolonged wear of CGM devices is or not the major causative factor for improvement in glucose variability among intensively insulin-treated persons with type 1 diabetes.

Glycemic Variability Impacted by SGLT2 Inhibitors and GLP 1 Agonists in Patients with Diabetes Mellitus: A Systematic Review and Meta-Analysis

To investigate the effect of sodium-glucose cotransporter 2 (SGLT-2) inhibitors and glucagon-like peptide 1 (GLP-1) agonists on glycemic variability (GV), the mean amplitude of glucose excursion (MAGE), mean blood glucose (MBG) levels, and percentage of time maintaining euglycemia were evaluated. Randomized controlled trials evaluating the efficacy of SGLT-2 inhibitors and GLP-1 agonists for treating people with diabetes were selected through searches of PubMed, EMBASE, and other databases. Sixteen studies were finally analyzed. There were no differences in the reductions in MAGE after treatment with SGLT-2 inhibitors or GLP-1 agonists (standardized mean difference (SMD) = -0.59, 95% CI = -0.82 to -0.36 vs. SMD = -0.43, 95% CI = -0.51 to -0.35, respectively), and treatment with SGLT-2 inhibitors was associated with an increased reduction in MBG levels (SMD = -0.56, 95% CI = -0.65 to -0.48, p < 0.00001). Monotherapy and add-on therapy with medications were correlated with MAGE and MBG level reductions. In conclusion, SGLT-2 inhibitors and GLP-1 agonists were associated with a reduction in GV and could be alternatives for treating people with diabetes.

Efficacy / safety balance of DPP-4 inhibitors versus SGLT2 inhibitors in elderly patients with type 2 diabetes

Dipeptidyl peptidase-4 inhibitors (DPP-4is) and sodium-glucose cotransporter type 2 inhibitors (SGLT2is) offer new options for the oral management of type 2 diabetes mellitus (T2DM), with the advantage in the elderly population to be devoid of a high risk of hypoglycaemia. SGLT2is have also shown benefits regarding cardiovascular (heart failure) and renal protection, including in patients with T2DM aged ≥ 65 years while DPP-4is have only proved cardiovascular and renal safety without superiority compared with placebo. The glucose-lowering efficacy of the two pharmacological classes is almost similar including in older patients with T2DM. However, the tolerance and safety profile may be highly different and overall more favourable with DPP-4is than with SGLT2is. Some adverse events have been reported with SGLT2is which may be more prevalent or severe in older patients than in younger patients. The present comprehensive review focuses on the benefit/risk balance in the elderly population with T2DM by comparing the profile of DPP-4is and SGLT2is regarding the following potential issues: metabolic disorders (hypoglycaemia and diabetic ketoacidosis); cardiac and vascular issues (atheromatous cardiovascular disease, heart failure, volume reduction hypotension, and lower limb amputations); renal endpoints including acute renal injury; risk of infections; digestive disorders; bone and skin adverse events; and cancer risk. Both DPP-4is and SGLT2is have their own advantages and disadvantages. Personalised treatment is recommended based upon the efficacy/safety profile of each drug class and individual patient characteristics that may be markedly different among the heterogeneous population of older individuals with T2DM.

Impact of glycemic variability on coronary and peripheral endothelial dysfunction in patients with coronary artery disease

BACKGROUND

Previous studies have reported that glucose variability leads to endothelial dysfunction and progression of coronary atherosclerosis. However, few studies have directly evaluated the relation between glucose variability and coronary endothelial function in patients with coronary artery disease (CAD).

METHODS

A total of 38 patients with chronic CAD and a history of coronary drug-eluting stent implantation were enroled. Coronary endothelial function was evaluated by measuring the coronary vasoreactivity using quantitative coronary angiography in the segment distal to implanted stent in response to intracoronary acetylcholine (ACh) infusion (10-7 mol/l). Peripheral endothelial function was also assessed with reactive hyperemia index (RHI). The mean amplitude of glycemic excursion (MAGE) was calculated as a primary metric of glucose variability using a flash glucose monitoring system.

RESULTS

Of 38 patients, 17 (45%) had diabetes mellitus. The mean levels of glycated hemoglobin, MAGE, and RHI were 6.3 ± 0.8%, 71.4 ± 29.8 mg/dl, and 1.85 ± 0.63. In the distal segment to coronary stent, lumen diameter was constricted by 0.6 ± 7.3% in response to intracoronary ACh infusion compared to that at baseline. While peripheral endothelial function assessed with RHI was not significantly associated with MAGE (r = -0.16, p = 0.35), coronary endothelial function was correlated with MAGE (r = -0.38, p = 0.02).

CONCLUSION

Greater glucose variability was significantly associated with coronary rather than peripheral endothelial dysfunction in patients with CAD, suggesting an impact of glucose variability on coronary atherosclerosis.

GPR120/FFAR4 Pharmacology: Focus on Agonists in Type 2 Diabetes Mellitus Drug Discovery

The G-protein coupled receptors (GPCRs) activated by free fatty acids (FFAs) have emerged as new and exciting drug targets, due to their plausible translation from pharmacology to medicines. This perspective aims to report recent research about GPR120/FFAR4 and its involvement in several diseases, including cancer, inflammatory conditions, and central nervous system disorders. The focus is to highlight the importance of GPR120 in Type 2 diabetes mellitus (T2DM). GPR120 agonists, useful in T2DM drug discovery, have been widely explored from a structure–activity relationship point of view. Since the identification of the first reported synthetic agonist TUG-891, the research has paved the way for the development of TUG-based molecules as well as new and different chemical entities. These molecules might represent the starting point for the future discovery of GPR120 agonists as antidiabetic drugs.

Glycemic Variability, Oxidative Stress, and Impact on Complications Related to Type 2 Diabetes Mellitus

Chronic hyperglycemia is an established risk factor for the development of complications in both type 1 and type 2 diabetes, but glycemic variability has emerged as a possible independent risk factor for diabetes complications, possibly through oxidative stress. In this review, methods to access glycemic variability and oxidative stress, as well as their correlations, are discussed. Non-pharmacological and pharmacological strategies are also debated to achieve better glycemic control, not only by HbA1c target but also with reduced glycemic fluctuations, possibly minimizing the risk of diabetes complications.

Repositioning medication for cardiovascular and cerebrovascular disease to delay the onset and prevent progression of Alzheimer's disease

Alzheimer's disease (AD) is a complex, progressive, neurodegenerative disorder. As with other common chronic diseases, multiple risk factors contribute to the onset and progression of AD. Many researchers have evaluated the epidemiologic and pathophysiological association between AD, cardiovascular diseases (CVDs), and cerebrovascular diseases (CBVDs), including commonly reported risk factors such as diabetes, hypertension, and dyslipidemia. Relevant therapies of CVDs/CBVDs for the attenuation of AD have also been empirically investigated. Considering the challenges of new drug development, in terms of cost and time, multifactorial approaches such as therapeutic repositioning of CVD/CBVD medication should be explored to delay the onset and progression of AD. Thus, in this review, we discuss our current understanding of the association between cardiovascular risk factors and AD, as revealed by clinical and non-clinical studies, as well as the therapeutic implications of CVD/CBVD medication that may attenuate AD. Furthermore, we discuss future directions by evaluating ongoing trials in the field.

Design, Synthesis, and Evaluation of a Series of Novel Super Long-Acting DPP-4 Inhibitors for the Treatment of Type 2 Diabetes

In the present work, a novel series of trifluoromethyl-substituted tetrahydropyran derivatives were rationally designed and synthesized as potent DPP-4 inhibitors with significantly improved duration time of action over current commercially available DPP-4 inhibitors. The incorporation of the trifluoromethyl group on the 6-position of the tetrahydropyran ring of omarigliptin with the configuration of (2R,3S,5R,6S) not only significantly improves the overall pharmacokinetic profiles in mice but also maintains comparable DPP-4 inhibition activities. Further preclinical development of compound 2 exhibited its extraordinary efficacy in vivo and good safety profile. Clinical studies of compound 2 (Haisco HSK7653) are now ongoing in China, which revealed that inhibitor 2 could serve as an efficient candidate with a once-biweekly therapeutic regimen.

Association between the Use of Dipeptidyl Peptidase 4 Inhibitors and the Risk of Dementia among Patients with Type 2 Diabetes in Taiwan

STUDY OBJECTIVES

Diabetes mellitus per se and its related therapy have been frequently associated with an increased risk of developing dementia. However, studies that explored the risk of dementia from the use of the novel oral antidiabetic medication dipeptidyl peptidase 4 inhibitor (DPP-4i) have been limited, especially in Asian populations. The present study aimed to determine the effect of DPP-4i on the subsequent risk of dementia among patients with type 2 diabetes (T2D) in Taiwan.

METHODS

This study utilized data from the Longitudinal Health Insurance Database between 2008 and 2015. We enrolled 2903 patients aged ≥50 years, who were on DPP-4i for a diagnosis of T2D and had no dementia. A total of 11,612 subjects were included and compared with a propensity score-matched control group who did not use DPP-4i (non-DPP-4i group). Survival analysis was performed to estimate and compare the risk of dementia-including Alzheimer's disease, vascular dementia, and other dementia types-between the two groups. Results: Both groups had a mean age of 68 years, had a preponderance of women (61.8%), and were followed up for a mean duration of 7 years. The risk of all-cause dementia was significantly lower in the DPP-4i group than in the non-DPP-4i group (hazard ratio (HR) 0.798; 95% confidence interval (CI) 0.681-0.883; p < 0.001), with a class effect. This trend was particularly observed for vascular dementia (HR 0.575; 95% CI 0.404-0.681; p < 0.001), but not in Alzheimer's disease (HR 0.891; 95% CI 0.712-1.265; p = 0.297). The Kaplan-Meier analysis showed that the preventive effect on dementia was positively correlated with the cumulative dose of DPP-4i. Conclusions: DPP-4i decreased the risk of dementia with a class effect, especially vascular dementia, but not in Alzheimer's disease. Our results provide important information on the drug choice when managing patients with T2D in clinical practice.