Extra-pancreatic effects of incretin-based therapies: potential benefit for cardiovascular-risk management in type 2 diabetes

Do GLP-1 Analogs Have a Place in the Treatment of PCOS? New Insights and Promising Therapies

Polycystic ovary syndrome (PCOS) is the most prevalent endocrinopathy in women of reproductive age. This condition is characterized by hyperandrogenism and either oligo- or anovulation. PCOS patients often present comorbidities such as obesity, insulin resistance, impaired glucose metabolism, dyslipidemia, hypertension, metabolic syndrome, and an increased risk of diabetes. Given the profound implications of metabolic impairment in PCOS, the accurate diagnosis and management of these facets are imperative. The first-line approach to treatment involves lifestyle modifications, including dietary adjustments and exercise aimed at achieving weight loss, a strategy consistently emphasized across the literature. Supplementation with probiotics, vitamin D, and L-carnitine have also provided additional benefits to patients. In select cases, pharmacological interventions are needed for optimal therapeutic results. The most common medications used in PCOS include metformin, thiazolidinediones, inositols, and two classes of antidiabetic agents: dipeptidyl peptidase-IV (DPP-IV) inhibitors, and sodium-glucose cotransporter-2 (SGLT-2) inhibitors. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a new addition to the therapeutic arsenal for the metabolic management of PCOS. GLP-1 receptor agonists cause insulin release in a glucose-dependent manner, yielding clinical benefits such as heightened satiety, reduced appetite, and appetite regulation. GLP-1RAs have demonstrated efficacy in reducing glycated hemoglobin levels and promoting weight loss while ameliorating hyperlipidemia. Prior to initiating GLP-1RA therapy, patients should undergo screening for contraindications, including history of pancreatitis, diabetic retinopathy, or thyroid cancer. The effects of treatment should be monitored using laboratory testing and body weight measurements. Effective communication between clinician and patient should be maintained with regular check-in for a period of 6 to 12 months.

Repurposing of Drugs for Cardiometabolic Disorders: An Out and Out Cumulation

Cardiometabolic disorders (CMD) is a constellation of metabolic predisposing factors for atherosclerosis such as insulin resistance (IR) or diabetes mellitus (DM), systemic hypertension, central obesity, and dyslipidemia. Cardiometabolic diseases (CMDs) continue to be the leading cause of mortality in both developed and developing nations, accounting for over 32% of all fatalities globally each year. Furthermore, dyslipidemia, angina, arrhythmia, heart failure, myocardial infarction (MI), and diabetes mellitus are the major causes of death, accounting for an estimated 19 million deaths in 2012. CVDs will kill more than 23 million individuals each year by 2030. Nonetheless, new drug development (NDD) in CMDs has been increasingly difficult in recent decades due to increased costs and a lower success rate. Drug repositioning in CMDs looks promising in this scenario for launching current medicines for new therapeutic indications. Repositioning is an ancient method that dates back to the 1960s and is mostly based on coincidental findings during medication trials. One significant advantage of repositioning is that the drug's safety profile is well known, lowering the odds of failure owing to undesirable toxic effects. Furthermore, repositioning takes less time and money than NDD. Given these facts, pharmaceutical corporations are becoming more interested in medication repositioning. In this follow-up, we discussed the notion of repositioning and provided some examples of repositioned medications in cardiometabolic disorders.

Obesity, Polycystic Ovary Syndrome, and Infertility: A New Avenue for GLP-1 Receptor Agonists

CONTEXT

Obesity is responsible for an increased risk of sub-fecundity and infertility. Obese women show poorer reproductive outcomes regardless of the mode of conception, and higher body mass index (BMI) is associated with poorer fertility prognosis. Polycystic ovary syndrome (PCOS) is one of the leading causes of infertility, and many women with PCOS are also overweight or obese.

EVIDENCE ACQUISITION

The aim of the present narrative review is to describe the mechanisms responsible for the development of infertility and PCOS in women with obesity/overweight, with a focus on the emerging role of glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1 RAs) as a therapeutic option for obese women with PCOS.

EVIDENCE SYNTHESIS

Weight reduction represents the most significant factor affecting fertility and pregnancy outcomes. Current experimental and clinical evidence suggests the presence of an underlying pathophysiological link between obesity, GLP-1 kinetic alterations, and PCOS pathogenesis. Based on the positive results in patients affected by obesity, with or without diabetes, the administration of GLP-1 RA (mainly liraglutide) alone or in combination with metformin has been investigated in women with obesity and PCOS. Several studies demonstrated significant weight loss and testosterone reduction, with mixed results relative to improvements in insulin resistance parameters and menstrual patterns.

CONCLUSIONS

The weight loss effects of GLP-1 RA offer a unique opportunity to expand the treatment options available to PCOS patients.

Blood pressure control in type 2 diabetes mellitus with arterial hypertension. The important ancillary role of SGLT2-inhibitors and GLP1-receptor agonists

Type 2 diabetes mellitus and arterial hypertension are major cardiovascular risks factors which shares metabolic and haemodynamic abnormalities as well as pathophysiological mechanisms. The simultaneous presence of diabetes and arterial hypertension increases the risk of left ventricular hypertrophy, congestive heart failure, and stroke, as compared to either condition alone. A number of guidelines recommend lifestyle measures such as salt restriction, weight reduction and ideal body weight mainteinance, regular physical activity and smoking cessation, together with moderation of alcohol consumption and high intake of vegetables and fruits, as the basis for reduction of blood pressure and prevention of CV diseases. Despite the availability of multiple drugs effective for hypertension, BP targets are reached in only 50 % of patients, with even fewer individuals with T2DM-achieving goals. It is established that new emerging classes of type 2 diabetes mellitus treatment, SGLT2 inhibitors and GLP1-receptor agonists, are efficacious on glucose control, and safe in reducing HbA1c significantly, without increasing hypoglycemic episodes. Furthermore, in recent years, many CVOT trials have demonstrated, using GLP1-RA or SGLT2-inihibitors compared to placebo (in combination with the usual diabetes medications) important benefits on reducing MACE (cardio-cerebral vascular events) in the diabetic population. In this hypothesis-driven review, we have examined the anti-hypertensive effects of these novel molecules of the two different classes, in the diabetic population, and suggest that they could have an interesting ancillary role in controlling blood pressure in type 2 diabetic patients.

Comparative effect of dipeptidyl-peptidase 4 inhibitors on laboratory parameters in patients with diabetes mellitus

Background

The purpose of this study was to evaluate and compare the effects on laboratory parameters among monotherapy with five DPP-4 inhibitors in patients with type 2 diabetes mellitus (DM).

Methods

We identified cohorts of new sitagliptin users (n = 879), vildagliptin users (n = 253), teneligliptin users (n = 260), alogliptin users (n = 237), and linagliptin users (n = 180) in patients with type 2 DM. We used a multivariate regression model to evaluate and compare the effects of the drugs on laboratory parameters including HbA1c concentration and serum concentrations of creatinine, estimated glomerular filtration rate, high density lipoprotein, total cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase among the five DPP-4 inhibitors up to 12 months.

Results

Our study showed a favorable effect on HbA1c concentration and a slightly unfavorable effect on serum creatinine concentration in users of the five DPP-4 inhibitors, a favorable effect on lipid metabolism in sitagliptin, vildagliptin, and alogliptin users, and a favorable effect on hepatic parameters in sitagliptin, alogliptin, and linagliptin users, in comparison of the baseline and exposure periods. However, there was no significant difference in mean change in the concentration of any laboratory parameter among the five groups of DPP-4 inhibitor users.

Conclusions

In this study, we showed the effect of five DPP-4 inhibitors on glycemic, renal, and lipid metabolism, and hepatic parameters. DPP-4 inhibitors are well-tolerated hypoglycemic drugs.

What is new in the landscape of insulin-sensitizing agents for polycystic ovary syndrome treatment

Polycystic ovary syndrome, the most common gynecological endocrinopathy, is burdened with a state of hyperinsulinemia and insulin resistance in 50–80% of affected women. Wherever the origin of these metabolic abnormalities lies, their pathogenetic role in determining, perpetuating, and worsening the clinical traits of the syndrome is ascertained. Many studies have already highlighted possible mechanisms: hyperinsulinemia and insulin resistance may contribute to hyperandrogenemia, chronic anovulation, and other comorbidities of the syndrome by differentially affecting the endocrine glands (ovaries, adrenals, and pituitary) and peripheral tissues (fat mass and skeletal muscle). Based on these evidences, in the past years, thorough research has been focused on the possible role of insulin-sensitizing agents in the treatment of polycystic ovary syndrome. Many compounds were tested to verify their efficacy against polycystic ovary syndrome–related metabolic dysfunction, both relying on previous acquired experiences in the field of diabetes mellitus and experimenting new agents, in particular, those belonging to the class of nutraceuticals. We sought to summarize the most relevant aspects of insulin-sensitizing treatments in polycystic ovary syndrome, by reporting the relevant literature on this topic and by keeping an attentive eye on the newly published international guidelines on polycystic ovary syndrome 2018. This overview encompasses metformin, thiazolidinediones, inositols, alpha-lipoic acid, and GLP1-R analogues. Starting from the analysis of the mechanisms of action, we anchored to the state of the art of the use of these drugs in polycystic ovary syndrome, to the most recent evidences for clinical practice and to the remaining open questions around indications, dose, treatment schedules, and side effects.

Renoprotection Provided by Dipeptidyl Peptidase-4 Inhibitors in Combination with Angiotensin Receptor Blockers in Patients with Type 2 Diabetic Nephropathy

Background:

Treatment with the dipeptidyl peptidase-4 inhibitors (DPP4i) and angiotensin receptor blockers (ARBs) in patients with type 2 diabetic nephropathy (DN) has not been well characterized. This study aimed to assess the renoprotection of this combined treatment in DN patients.

Methods:

A total of 159 type 2 DN patients from 2013 to 2015 were enrolled retrospectively from a prospective DN cohort at the National Clinical Research Center of Kidney Diseases, Jinling Hospital (China). Fifty-seven patients received DPP4i and ARB treatment, and 102 patients were treated with ARBs alone. All patients were followed up for at least 12 months. Statistical analyses were performed using Stata version 12.0.

Results:

There were no significant differences at baseline for age, sex, body mass index, duration of diabetes, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and estimated glomerular filtration rate (eGFR) between the two groups. Antihypertensive and antidiabetic medication use was similar in each group except calcium channel antagonists (P = 0.032). No significant changes in FBG and HbA1c were observed in the two groups after treatment. The eGFR decreased slower in the DPP4i + ARB group than in the ARB group at 12 months (Δ12 months: −2.48 ± 13.86 vs. −6.81 ± 12.52 ml·min^–1·1.73m^–2, P = 0.044). In addition, proteinuria was decreased further in the DPP4i + ARB group than in the ARB group after 24 months of treatment (Δ24 months: −0.18 [−1.00, 0.17] vs. 0.32 [−0.35, 0.88], P = 0.031). There were 36 patients with an eGFR decrease of more than 30% over 24 months. After adjusting for FBG, HbA1c, and other risk factors, DPP4i + ARB treatment was still associated with a reduced incidence of an eGFR decrease of 20% or 30%.

Conclusions:

The combined treatment of DPP4i and ARBs is superior to ARBs alone, as evidenced by the greater proteinuria reduction and lower eGFR decline. In addition, the renoprotection of DPP4i combined with ARBs was independent of glycemic control.

Modulation of GLP-1 Levels by a Genetic Variant That Regulates the Cardiovascular Effects of Intensive Glycemic Control in ACCORD

OBJECTIVE

A genome-wide association study in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial identified two markers (rs57922 and rs9299870) that were significantly associated with cardiovascular mortality during intensive glycemic control and could potentially be used, when combined into a genetic risk score (GRS), to identify patients with diabetes likely to derive benefit from intensive control rather than harm. The aim of this study was to gain insights into the pathways involved in the modulatory effect of these variants.

RESEARCH DESIGN AND METHODS

Fasting levels of 65 biomarkers were measured at baseline and at 12 months of follow-up in the ACCORD-Memory in Diabetes (ACCORD-MIND) MRI substudy (n = 562). Using linear regression models, we tested the association of the GRS with baseline and 12-month biomarker levels, and with their difference (Δ), among white subjects, with genotype data (n = 351) stratified by intervention arm.

RESULTS

A significant association was observed between GRS and ΔGLP-1 (glucagon-like peptide 1, active) in the intensive arm (P = 3 × 10-4). This effect was driven by rs57922 (P = 5 × 10-4). C/C homozygotes, who had been found to derive cardiovascular benefits from intensive treatment, showed a 22% increase in GLP-1 levels during follow-up. By contrast, T/T homozygotes, who had been found to experience increased cardiac mortality with intensive treatment, showed a 28% reduction in GLP-1 levels. No association between ΔGLP-1 and GRS or rs57922 was observed in the standard treatment arm.

CONCLUSIONS

Differences in GLP-1 axis activation may mediate the modulatory effect of variant rs57922 on the cardiovascular response to intensive glycemic control. These findings highlight the importance of GLP-1 as a cardioprotective factor.

Comparative effects of liraglutide 3 mg vs structured lifestyle modification on body weight, liver fat and liver function in obese patients with non-alcoholic fatty liver disease: A pilot randomized trial

We compared the effects of weight loss induced by the glucagon-like peptide 1-agonist liraglutide with a structured lifestyle intervention in obese adults with non-alcoholic fatty liver disease (NAFLD). Obese (body mass index ≥30 kg/m² , mean weight 96.0 ± 16.3 kg) non-diabetic Asian adults, with NAFLD diagnosed by liver fat fraction (LFF) ≥ 5.5% on magnetic resonance imaging without other causes of hepatic steatosis, were randomized to a supervised program of dieting (restriction by 400 kilocalories/d) plus moderate-intensity aerobic exercise (~200 min/wk; DE group, n = 12), or liraglutide at the 3 mg daily dose approved for weight loss (LI group, n = 12), for 26 weeks. Both DE and LI groups had significant (P < .01) and similar reductions in weight (-3.5 ± 3.3 vs -3.5 ± 2.1 kg, respectively, P = .72), LFF (-8.9 ± 13.4 vs -7.2% ± 7.1%, P = .70), serum alanine aminotransferase (-42 ± 46 vs -34 ± 27 U/L, P = .52) and aspartate aminotransferase (-23 ± 24 vs -18 ± 15 U/L, P = .53). In this first randomized study comparing the 2 weight-loss modalities for improving NAFLD, liraglutide was as effective as structured lifestyle modification.

Dose Modification of Antidiabetic Agents in Patients with Type 2 Diabetes Mellitus and Heart Failure

Heart failure is the most common comorbidity of diabetes. The incidence of heart failure in patients with diabetes is about 9%-22%, which is four times higher Than that in patients without diabetes. Heart failure and diabetes are collectively associated with increased morbidity and mortality compared to either condition alone. Several epidemiological studies have demonstrated an increased risk of heart failure in patients with diabetes; moreover, poor glycemic control accounts for the increased risk of heart failure. At present, several oral (metformin, sulfonylureas, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, etc.) as well as injectable (insulins, glucagon-like peptide 1 receptor agonists) antidiabetic agents are available. However, optimal treatment strategy to achieve adequate glycemic control in patients with type 2 diabetes mellitus (T2DM) and heart failure has not been well studied. In the view of rising prevalence of heart failure in patients with diabetes mellitus, clinicians need to understand the potential implications of antidiabetic agents in patients with heart failure. A group of experts from across India were involved in a consensus meeting in Pondicherry during the National Insulin Summit in November 2015. They evaluated agents currently available for the treatment of diabetes looking at existing scientific evidence relevant to each class of therapy. In addition, the existing guidelines and prescribing literature available with all these agents were also reviewed. Findings from the expert evaluations were then factored into the national context incorporating personal experience and common clinical practices in India. The purpose of this consensus document is to assist the clinicians while treating patients with T2DM and heart failure.

Effects of liraglutide on cardiovascular risk biomarkers in patients with type 2 diabetes and albuminuria: A sub-analysis of a randomized, placebo-controlled, double-blind, crossover trial

We assessed the effects of liraglutide treatment on five cardiovascular risk biomarkers, reflecting different pathophysiology: tumour necrosis factor (TNF)-α; soluble urokinase plasminogen activator receptor (suPAR); mid-regional pro-adrenomedullin (MR-proADM); mid-regional pro-atrial natriuretic peptide (MR-proANP); and copeptin, in people with type 2 diabetes with albuminuria. In a randomized, double-blind, placebo-controlled, crossover trial we enrolled people with type 2 diabetes and persistent albuminuria (urinary albumin-to-creatinine ratio [UACR] >30 mg/g) and estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m² . Participants received liraglutide (1.8 mg/d) and matched placebo for 12 weeks, in random order. The primary endpoint was change in albuminuria; this was a prespecified sub-study. A total of 32 participants were randomized, of whom 27 completed the study. TNF-α level was 12% (95% confidence interval [CI] 3; 20) lower after liraglutide treatment compared with placebo (P = .012); MR-proADM level was 4% (95% CI 0; 8) lower after liraglutide treatment compared with placebo (P = .038), and MR-proANP level was 13% (95% CI 4; 21) lower after liraglutide treatment compared with placebo (P = .006). In the present study, we showed anti-inflammatory effects of liraglutide treatment, reflected in reductions in levels of TNF-α and MR-proADM, while the reduction in MR-proANP levels may represent a clinically relevant benefit with regard to heart failure.

Glucagon-Like Peptide-1 and Its Class B G Protein-Coupled Receptors: A Long March to Therapeutic Successes

The glucagon-like peptide (GLP)-1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that mediates the action of GLP-1, a peptide hormone secreted from three major tissues in humans, enteroendocrine L cells in the distal intestine, α cells in the pancreas, and the central nervous system, which exerts important actions useful in the management of type 2 diabetes mellitus and obesity, including glucose homeostasis and regulation of gastric motility and food intake. Peptidic analogs of GLP-1 have been successfully developed with enhanced bioavailability and pharmacological activity. Physiologic and biochemical studies with truncated, chimeric, and mutated peptides and GLP-1R variants, together with ligand-bound crystal structures of the extracellular domain and the first three-dimensional structures of the 7-helical transmembrane domain of class B GPCRs, have provided the basis for a two-domain-binding mechanism of GLP-1 with its cognate receptor. Although efforts in discovering therapeutically viable nonpeptidic GLP-1R agonists have been hampered, small-molecule modulators offer complementary chemical tools to peptide analogs to investigate ligand-directed biased cellular signaling of GLP-1R. The integrated pharmacological and structural information of different GLP-1 analogs and homologous receptors give new insights into the molecular determinants of GLP-1R ligand selectivity and functional activity, thereby providing novel opportunities in the design and development of more efficacious agents to treat metabolic disorders.

GLP-1 receptor agonists in the treatment of polycystic ovary syndrome

INTRODUCTION

Polycystic ovarian syndrome (PCOS) affects many women of child-bearing age and is characterized by hyperandrogenism, ovulatory and metabolic dysfunction. A primary treatment goal is weight reduction. The weight loss effects of glucagon-like peptide-1 receptor agonists (GLP-1RA), previously demonstrated in diabetic and obese non-diabetic patients, offer a unique opportunity to expand the medical options available to PCOS patients. Areas covered: Available clinical trials of glucagon-like peptide-1 receptor agonist therapy in PCOS were reviewed. Literature was searched from PubMed using appropriate search terms up to November 2016. Expert commentary: The available studies of GLP-1 RA therapy in the treatment of excess body weight in women with PCOS demonstrate that exenatide and liraglutide are effective in weight reduction either as monotherapy or in combination with metformin. A few studies showed that androgens may be modestly decreased and menstrual frequency may be increased. Eating behavior may be improved with liraglutide therapy. Glucose parameters are generally improved. GLP-1RAs were well-tolerated, with nausea being the most significant adverse side effect. Barriers to utilization may be the short duration studies, lack of familiarity of the medication, the route of administration (injection) and the variable outcomes on ovulation and hyperandrogenism.

The effects of GLP-1 based therapies on postprandial haemodynamics: Two randomised, placebo-controlled trials in overweight type 2 diabetes patients

AIMS

To assess the effects of glucagon-like peptide (GLP)-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors on postprandial haemodynamics.

METHODS

57 patients with type 2 diabetes (mean±SD age 62.8±6.9years; BMI 31.8±4.1kg/m²; HbA_1c 7.3±0.6%) were included in an acute (exenatide- or placebo-infusion) and 12-week (liraglutide, sitagliptin or placebo) randomised, placebo-controlled, double-blind trial. Systemic haemodynamics (oscillometric technique and finger photoplethysmography), vascular stiffness (tonometry), and sympathetic nervous system (SNS)-activity (heart rate variability) were determined in the fasting state and following a standardised mixed meal.

RESULTS

In both studies, postprandial blood pressure (BP) decreased during placebo-intervention. Compared with placebo, acute exenatide-infusion increased postprandial diastolic BP (6.7 [95%-confidence interval 3.6-9.9]mmHg, p<0.001) and vascular resistance (683.6 [438.5-928.8]dyn*s/cm⁵/1.73m², p<0.001), while cardiac index decreased (0.6 [0.40.8]L/min/1.73m²; p<0.001). Systolic BP, augmentation index and SNS-activity were unaffected. Twelve-week liraglutide-treatment did not affect postprandial haemodynamics, while sitagliptin decreased diastolic BP (3.5 [0.0-6.9] mmHg; p=0.050), vascular resistance (309.9 [66.6-553.1]dyn*s/cm⁵/1.73m²; p=0.013) and cardiac index (0.3 [0.0-0.6]L/min/1.73m²; p=0.040), compared with placebo. Neither liraglutide nor sitagliptin affected SNS-activity or augmentation index. All treatments significantly lowered postprandial glucose levels.

CONCLUSIONS

Acute exenatide-infusion prevented the meal-induced decline in diastolic BP, although prolonged liraglutide intervention did not affect postprandial haemodynamics. The meal-induced drop in BP was augmented during sitagliptin-treatment.

What Are We Learning from the FDA-Mandated Cardiovascular Outcome Studies for New Pharmacological Antidiabetic Agents?

Cardiovascular disease (CVD) is common in patients with diabetes. For these patients, clinicians should seek diabetes treatment that is beneficial rather than harmful in relation to CVD. Until recently, there have been many treatments for hyperglycemia, whose impact on CVD has been controversial. The aims of this review are to evaluate the effectiveness of antihyperglycemic medications on risk factors for CVD and to examine the impact of these drugs on CVD in cardiovascular (CV) outcome trials. In this article, we summarize current knowledge about the impacts of these drugs on various risk factors as well as CV outcomes. We identify the recent emergence of trials with antihyperglycemic agents showing newly discovered CV benefits as well as past trials with antihyperglycemic agents not showing much benefit on CV events. Rather than focusing on treatment strategies, we review the effects of individual drug classes on CV outcomes. We also briefly review goal-driven glycemia reduction and its impact on CVD. We conclude that antihyperglycemic agents are associated with improvement in CV risk factors in patients with diabetes and insulin resistance; in fact, a few drugs reduced CV events in randomized CV outcome trials. Therefore, the use of these drugs is appropriate for reducing glucose and decreasing CV event risk in a select subpopulation.

Efficacy of different dipeptidyl peptidase-4 (DPP-4) inhibitors on metabolic parameters in patients with type 2 diabetes undergoing dialysis

Hyperglycemia is associated with increased mortality and morbidity in patients with type 2 diabetes mellitus (T2DM) who are undergoing dialysis. Although dipeptidyl peptidase-4 (DPP-4) inhibitors have been widely used in end-stage renal disease (ESRD) patients with T2DM, there are few studies on their efficacy in this population. We studied the effect of 3 different DPP-4 inhibitors on metabolic parameters in ESRD patients with T2DM.Two hundred ESRD patients with T2DM who were treated with DPP-4 inhibitors (sitagliptin, vildagliptin, or linagliptin) were enrolled and analyzed retrospectively. The changes in glycated hemoglobin (HbA1c), fasting plasma glucose, and lipid profiles were assessed before and after 3 months of treatment with DPP-4 inhibitors. Subgroup analysis was done for each hemodialysis (HD) and peritoneal dialysis (PD) group.There was no significant difference in the decrease in the HbA1c level among sitagliptin, vildagliptin, and linagliptin treatment groups (-0.74 ± 1.57, -0.39 ± 1.45, and -0.08 ± 1.40, respectively, P = 0.076). The changes in fasting blood glucose and lipid profiles were also not significantly different. In HD patients (n = 115), there was no difference in the HbA1c level among the 3 groups. In contrast, in PD patients (n = 85), HbA1c was reduced more after 3 months of treatment with sitagliptin compared with vildagliptin and linagliptin (-1.58 ± 0.95, -0.46 ± 0.98, -0.04 ± 1.22, respectively, P = 0.001).There was no significant difference in the glucose-lowering effect between the different DPP-4 inhibitors tested in ESRD patients. In PD patients, sitagliptin tends to lower the HbA1c level more than the other inhibitors. The glucose-lowering efficacy of the 3 DPP-4 inhibitors was comparable.

Common medications used by patients with type 2 diabetes mellitus: what are their effects on the lipid profile?

Dyslipidemia is the most fundamental risk factor for atherosclerotic cardiovascular disease (ASCVD). In clinical practice, many commonly prescribed medications can alter the patient's lipid profile and, potentially, the risk for ASCVD-either favorably or unfavorably. The dyslipidemia observed in type 2 diabetes mellitus (T2DM) can be characterized as both ominous and cryptic, in terms of unrecognized, disproportionately elevated atherogenic cholesterol particle concentrations, in spite of deceptively and relatively lower levels of low-density lipoprotein cholesterol (LDL-C). Several factors, most notably insulin resistance, associated with the unfavorable discordance of elevated triglyceride (TG) levels and low levels of high-density lipoprotein cholesterol (HDL-C), have been shown to correlate with an increased risk/number of ASCVD events in patients with T2DM. This review focuses on known changes in the routine lipid profile (LDL-C, TGs, and HDL-C) observed with commonly prescribed medications for patients with T2DM, including antihyperglycemic agents, antihypertensive agents, weight loss medications, antibiotics, analgesics, oral contraceptives, and hormone replacement therapies. Given that the risk of ASCVD is already elevated for patients with T2DM, the use of polypharmacy may warrant close observation of overall alterations through ongoing lipid-panel monitoring. Ultimately, the goal is to reduce levels of atherogenic cholesterol particles and thus the patient's absolute risk.

Inflammation Meets Metabolic Disease: Gut Feeling Mediated by GLP-1

Chronic diseases, such as obesity and diabetes, cardiovascular, and inflammatory bowel diseases (IBD) share common features in their pathology. Metabolic disorders exhibit strong inflammatory underpinnings and vice versa, inflammation is associated with metabolic alterations. Next to cytokines and cellular stress pathways, such as the unfolded protein response (UPR), alterations in the enteroendocrine system are intersections of various pathologies. Enteroendocrine cells (EEC) have been studied extensively for their ability to regulate gastrointestinal motility, secretion, and insulin release by release of peptide hormones. In particular, the L-cell-derived incretin hormone glucagon-like peptide 1 (GLP-1) has gained enormous attention due to its insulinotropic action and relevance in the treatment of type 2 diabetes (T2D). Yet, accumulating data indicate a critical role for EEC and in particular for GLP-1 in metabolic adaptation and in orchestrating immune responses beyond blood glucose control. EEC sense the lamina propria and luminal environment, including the microbiota via receptors and transporters. Subsequently, mediating signals by secreting hormones and cytokines, EEC can be considered as integrators of metabolic and inflammatory signaling. This review focuses on L cell and GLP-1 functions in the context of metabolic and inflammatory diseases. The effects of incretin-based therapies on metabolism and immune system are discussed and the interrelation and common features of metabolic and immune-mediated disorders are highlighted. Moreover, it presents data on the impact of inflammation, in particular of IBD on EEC and discusses the potential role of the microbiota as link between nutrients, metabolism, immunity, and disease.

Balancing benefits and risks in patients receiving incretin-based therapies: focus on cardiovascular and pancreatic side effects

Incretin-based therapies either increase endogenous levels of glucagon-like peptide-1 by prolonging its half-life (DPP-4 inhibitors) or directly stimulate its receptor (glucagon-like peptide-1 analogues; GLP-1 RA). They are currently widely used for the treatment of patients with type 2 diabetes mellitus owing to good antidiabetic efficacy, low risk of hypoglycemia, and relatively few other side effects. They also offer potential additional benefits such as weight neutrality or weight loss, positive effects on blood pressure and lipid levels, and potential cardio- and neuroprotectivity. Some experimental and clinical studies have raised concerns with respect to potential cardiovascular and pancreatic side effects of these therapies such as increased risk of heart failure with DPP-4 inhibitors as well as acute pancreatitis and pancreatic cancer with both classes. The available data are at present not robust enough to enable firm conclusions regarding these potential associations. Nevertheless, some recent data suggest a possibility of slightly increased risk of acute pancreatitis with GLP-1 RAs while they do not indicate increased risk of pancreatic cancer. Ongoing cardiovascular outcome trials will shed more light on the possible cardioprotective effects of incretin-based therapies as well as on the possible interconnection of DPP-4 inhibitors and heart failure.

The role of dipeptidyl peptidase 4 inhibitors in fat metabolism in patients with type 2 diabetes and obesity

Objective. To evaluate the influence of combined therapy of sitagliptin and metformin on fat metabolism in patients with type 2 diabetes mellitus.Methods. The study included 82 patients (age, 55.3±9.1 years) with obesity and lipid metabolism disorders. None of the patients had reached their target glycated haemoglobin levels after metformin and diet therapy. Patients in group 1 (n=42) received 1.5–2-g metformin daily before the study and were switched to a formulation of 100-mg sitagliptin and 2-g metformin once a day. Patients in group 2 (n=40) were on a diet therapy before inclusion and were started on 2-g metformin/day. The following were evaluated at baseline and after 6 months of therapy: fasting glucose levels, postprandial glucose levels, glycated haemoglobin, weight, body mass index, waist circumference and lipid profile; insulin, proinsulin, leptin and adiponectin levels; insulin resistance using the homeostatic model assessment (HOMA) of β-cell function (HOMA-β) and insulin resistance (HOMA-IR). In addition, magnetic resonance imaging was performed to assess the amount of visceral fat for the total cohort.Results. After 6 months, glycated haemoglobin decreased by 18.52% (p 0.001) in group 1 and by 8.17% (p 0.001) in group 2. Fasting plasma glucose and postprandial glucose levels in group 1 were reduced by 21% (p 0.001) and 26.35% (p 0.001), respectively; the corresponding reductions in group 2 were 1.45% (p 0.05) and 5.31% (p 0.05), respectively. HOMA-β increased by 33% in group 1 (p 0.001) and by 11% in group 2 (p 0.05). Adiponectin levels increased by 27.06% (p 0.001) in group 1 and by 7.16% in group 2 (p 0.001). Leptin levels were reduced by 30.47% (p 0.001) in group 1 and by 5.41% in group 2 (p 0.001). Magnetic resonance imaging showed a 7.52% reduction in visceral fat for group 1 (p 0.001) and a 1.76% reduction for group 2 (p 0.01). The comparison of subcutaneous fat dynamics did not show statistically significant differences between the groups.Conclusion. Compared with metformin monotherapy, sitagliptin and metformin combination therapy had a prominent effect on non-glycaemic parameters, with more marked decreases in visceral fat and leptin and increases in adiponectin levels.

GLP-1 receptor agonists: Nonglycemic clinical effects in weight loss and beyond

OBJECTIVE

Glucagon-like peptide-1 (GLP-1) receptor agonists are indicated for treatment of type 2 diabetes since they mimic the actions of native GLP-1 on pancreatic islet cells, stimulating insulin release, while inhibiting glucagon release, in a glucose-dependent manner. The observation of weight loss has led to exploration of their potential as antiobesity agents, with liraglutide 3.0 mg day(-1) approved for weight management in the US on December 23, 2014, and in the EU on March 23, 2015. This review examines the potential nonglycemic effects of GLP-1 receptor agonists.

METHODS

A literature search was conducted to identify preclinical and clinical evidence on nonglycemic effects of GLP-1 receptor agonists.

RESULTS

GLP-1 receptors are distributed widely in a number of tissues in humans, and their effects are not limited to the well-recognized effects on glycemia. Nonglycemic effects include weight loss, which is perhaps the most widely recognized nonglycemic effect. In addition, effects on the cardiovascular, neurologic, and renal systems and on taste perception may occur independently of weight loss.

CONCLUSIONS

GLP-1 receptor agonists may provide other nonglycemic clinical effects besides weight loss. Understanding these effects is important for prescribers in using GLP-1 receptor agonists for diabetic patients, but also if approved for chronic weight management.

Teneligliptin : expectations for its pleiotropic action

INTRODUCTION

The main aim in the management of diabetes mellitus is to prevent the development of its complications. Large fluctuations in glucose levels may increase the risk of complications, so improved control of glucose fluctuations, in addition to management of chronic hyperglycemia, could represent an important goal in diabetes pharmacotherapy.

AREAS COVERED

Pre-clinical and clinical studies suggest that poor control of blood glucose fluctuations contributes to progression of diabetic vascular complications. Dipeptidyl peptidase (DPP)-4 inhibitors are one of several drug classes used to manage diabetes, and the potential vasoprotective effects of DPP-4 inhibition have attracted attention in recent years. The DPP-4 inhibitor teneligliptin was approved in Japan in 2012 and in Korea in 2014. Teneligliptin differs in its structural and pharmacokinetic characteristics compared with other drugs in the same class. It appears to have potent, sustained effects on glycemic control, thereby reducing the complications of hypoglycemia and postprandial hyperglycemia. Because of its effects on vascular function, teneligliptin may be beneficial in patients at high risk of cardiovascular disease.

EXPERT OPINION

The possible pleiotropic effects of teneligliptin, such as those on endothelial function and metabolic syndrome, are of great interest. This review examines these effects and their potential clinical relevance.

Pleiotropic effects of type 2 diabetes management strategies on renal risk factors

In parallel with the type 2 diabetes pandemic, diabetic kidney disease has become the leading cause of end-stage renal disease worldwide, and is associated with high cardiovascular morbidity and mortality. As established in landmark randomised trials and recommended in clinical guidelines, prevention and treatment of diabetic kidney disease focuses on control of the two main renal risk factors, hyperglycaemia and systemic hypertension. Treatment of systemic hypertension with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers is advocated because these drugs seem to exert specific renoprotective effects beyond blood pressure lowering. Emerging evidence shows that obesity, glomerular hyperfiltration, albuminuria, and dyslipidaemia might also adversely affect the kidney in diabetes. Control of these risk factors could have additional benefits on renal outcome in patients with type 2 diabetes. However, despite multifactorial treatment approaches, residual risk for the development and progression of diabetic kidney disease in patients with type 2 diabetes remains, and novel strategies or therapies to treat the disease are urgently needed. Several drugs used in the treatment of type 2 diabetes are associated with pleiotropic effects that could favourably or unfavourably change patients' renal risk profile. We review the risk factors and treatment of diabetic kidney disease, and describe the pleiotropic effects of widely used drugs in type 2 diabetes management on renal outcomes, with special emphasis on antihyperglycaemic drugs.

Implications of incretin-based therapies on cardiovascular disease

BACKGROUND

Incretin-based therapies offer another treatment option for patients with type 2 diabetes. Agents that provide glycaemic control in addition to attenuating cardiovascular disease (CVD) risk factors are important for diabetes management. This review will focus on the off-target effects of incretin-based therapies on CVD risk factors [body weight, blood pressure (BP), lipid profile and albuminuria], major adverse cardiovascular events (MACE), heart failure (HF) and beta-cell preservation.

METHODS

A literature search was conducted to identify English-language publications for incretin-based therapies evaluating the following off-target end-points: body weight, BP, lipid profile, albuminuria, MACE, HF and beta-cell function. Randomised controlled trials (RCTs) were prioritised as the primary source of information.

RESULTS

Overall, incretin-based therapies have shown beneficial effects on CVD risk factors, and glucagon-like peptide 1 (GLP-1) receptor agonists appear to have a more pronounced effect compared with dipeptidyl peptidase-4 inhibitors. RCTs are being conducted to determine if these positive effects on CVD risk factors translate to a reduction in MACE. To date, these studies have not shown an increase in MACE. A signal of increased hospitalisations for HF was observed with saxagliptin, warranting continued evaluation and vigilance in high-risk patients. In addition, incretin-based therapies have shown positive effects on measures of beta-cell function supporting their durability in the management of diabetes.

CONCLUSIONS

Incretin-based therapies are an important treatment option for patients with type 2 diabetes, offering beneficial effects on CVD risk factors without increasing MACE.

Liraglutide reduces the body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients

AIM

To investigate the effects of liraglutide, a glucagon-like peptide-1 (GLP-1) receptor activator, on body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients.

METHODS

A total of 328 Chinese overweight and obese type 2 diabetic patients were included in this multi-center, open-labeled and self-controlled clinical study. The patients were subcutaneously injected with liraglutide once daily for 24 weeks as add-on therapy to their previous hypoglycemic treatments. Statistical analyses were performed using SPSS software package version 11.5 for Windows.

RESULTS

Liraglutide treatment caused significant reduction of the mean body weight (from 86.61±14.09 to 79.10±13.55 kg) and waist circumference (from 101.81±13.96 to 94.29±14.17 cm), resulting in body weight lose of 5%-10% in 43.67% patients, and body weight loss above 10% in 34.06% patients, who had significant lower plasma creatinine levels. Baseline waist circumference, BMI and HOMA-IR were independently correlated with the body weight loss. Furthermore, liraglutide treatment significantly decreased HbA1c levels (from 8.66%±2.17% to 6.92%±0.95%) with HbA1c<7.0% in 35.37% patients, who had a significantly lower baseline level of HbA1c, but higher baseline levels of C peptide and glucagon. Moreover, liraglutide treatment resulted in greater body weight loss in patients with a long duration of diabetes, and better glycemic control in patients with a short duration of diabetes.

CONCLUSION

Liraglutide significantly reduces body weight and waist circumference in Chinese overweight and obese type 2 diabetic patients. Patients with apparent visceral obesity, insulin resistance and a long duration of diabetes may have greater body weight loss; whereas patients with high insulin-secreting ability, hyperglucagonemia, and short-duration diabetes may obtain better glycemic control with liraglutide.

Correlation between baseline characteristics and clinical outcomes in a large population of diabetes patients treated with liraglutide in a real-world setting in Italy

PURPOSE

Treatment with liraglutide in randomized controlled trials is associated with significant reductions in glycated hemoglobin (HbA1c) and weight loss in type 2 diabetes patients. The aim of this retrospective observational study was to investigate correlations of glycemic control and weight outcomes with baseline characteristics of patients starting liraglutide in outpatient clinics in Italy.

METHODS

Type 2 diabetes patients were followed from baseline to 4, 8, and 12 months. Changes in glycemic parameters, weight, blood pressure, and lipids were assessed. Subanalyses were performed according to baseline characteristics. Multivariate linear and logistic regressions were used to assess correlations between glycemic efficacy, weight reduction, and liraglutide discontinuation after 12 months and baseline characteristics.

FINDINGS

Four hundred and eighty-one patients were included. Mean (SD) age at baseline was 57.3 (9.2) years, diabetes duration was 9.5 (6.8) years, weight was 106.7 (20.8) kg, body mass index (BMI; calculated as kg/m(2)) was 37.1 (6.6), HbA1c was 8.7% (1.3%), fasting plasma glucose was 168.5 (45.3) mg/dL; 38.2% were treated previously with insulin and 52.2% were treated with metformin alone. After 12 months, mean (SD) changes were HbA1c -1.2% (1.4%), fasting plasma glucose -28.3 (41.1) mg/dL, weight -3.5 (5.8) kg, BMI -1.3 (2.1), waist circumference -2.6 (6.7) cm (all, P < 0.001). Drop in weight and HbA1c did not differ between baseline BMI classes ≤30 or >30. Weight loss was unchanged among diabetes duration quartiles, and HbA1c reduction was significantly greater in patients with ≤4 years of diabetes duration (P = 0.01). Non-insulin-treated patients reached HbA1c ≤7% significantly more often than treated patients (44.2% vs 21.2%; odds ratio = 2.94; P < 0.001) and had significantly greater weight loss (-4.5 [8.2] kg vs -2.6 [5.4] kg; P = 0.03). Patients on metformin reached HbA1c target more frequently than others (43.1% vs 29.7%; odds ratio = 1.80; 95% CI, 1.05-3.07). Significant positive determinants for HbA1c reduction after 12 months were baseline HbA1c, age, and prior metformin monotherapy, and weight loss at 12 months was positively correlated with baseline weight, and negatively correlated with prior insulin treatment. Overall, 5.0% of patients interrupted liraglutide before the 12th month due to lack of glycemic control; they were less frequently treated with metformin only before liraglutide (29.2% vs 50.2%; P = 0.04).

IMPLICATIONS

Treatment with liraglutide in a real-world setting is associated with low therapy failure, good glycemic response, weight loss, and improvement in systolic blood pressure and lipid profile. The HbA1c drop did not differ among baseline BMI classes, indicating that efficacy is maintained in patients with lower BMI. The probability of reaching HbA1c ≤7% was significantly higher in patients previously treated with metformin alone and without any previous insulin. This could reinforce the hypothesis that better results with liraglutide could be achieved in patients after early metformin failure.

The association of the treatment with glucagon-like peptide-1 receptor agonist exenatide or insulin with cardiovascular outcomes in patients with type 2 diabetes: a retrospective observational study

BACKGROUND

To evaluate the association of treatment with glucagon-like peptide-1 (GLP-1) receptor agonist exenatide and/or insulin on macrovascular outcomes in patients with type 2 diabetes (T2DM).

METHODS

We conducted a retrospective longitudinal pharmaco-epidemiological study using large ambulatory care data to evaluate the risks of heart failure (HF), myocardial infarction (MI) and stroke in established T2DM patients who received a first prescription of exenatide twice daily (EBID) or insulin between June 2005 and May 2009, with follow-up data available until December 2012. Three treatment groups were: EBID with oral antidiabetes drugs (OADs) (EBID, n = 2804), insulin with OADs (Insulin, n = 28551), and those who changed medications between EBID and insulin or had combination of EBID and insulin during follow-up, along with OADs (EBID + insulin, n = 7870). Multivariate Cox-regression models were used to evaluate the association of treatment groups with the risks of macrovascular events.

RESULTS

During a median 3.5 years of follow-up, cardiovascular event rates per 1000 person-years were significantly lower for the EBID and EBID + insulin groups compared to the insulin group (HF: 4.4 and 6.1 vs. 17.9; MI: 1.1 and 1.2 vs. 2.5; stroke: 2.4 and 1.8 vs. 6.1). Patients in the EBID/EBID + insulin group had significantly reduced risk of HF, MI and stroke by 61/56%, 50/38% and 52/63% respectively, compared to patients in the insulin group (p < 0.01).

CONCLUSIONS

Treatment with exenatide, with or without concomitant insulin was associated with reduced macrovascular risks compared to insulin; although inherent potential bias in epidemiological studies should be considered.

SIRT1 mediates the effect of GLP-1 receptor agonist exenatide on ameliorating hepatic steatosis

GLP-1 and incretin mimetics, such as exenatide, have been shown to attenuate hepatocyte steatosis in vivo and in vitro, but the specific underlying mechanism is unclear. SIRT1, an NAD(+)-dependent protein deacetylase, has been considered as a crucial regulator in hepatic lipid homeostasis by accumulated studies. Here, we speculate that SIRT1 might mediate the effect of the GLP-1 receptor agonist exenatide (exendin-4) on ameliorating hepatic steatosis. After 8 weeks of exenatide treatment in male SIRT1(+/-) mice challenged with a high-fat diet and their wild-type (WT) littermates, we found that lipid deposition and inflammation in the liver, which were improved dramatically in the WT group, diminished in SIRT1(+/-) mice. In addition, the protein expression of SIRT1 and phosphorylated AMPK was upregulated, whereas lipogenic-related protein, including SREBP-1c and PNPLA3, was downregulated in the WT group after exenatide treatment. However, none of these changes were observed in SIRT1(+/-) mice. In HepG2 cells, exendin-4-reversed lipid deposition induced by palmitate was hampered when SIRT1 was silenced by SIRT1 RNA interference. Our data demonstrate that SIRT1 mediates the effect of exenatide on ameliorating hepatic steatosis, suggesting the GLP-1 receptor agonist could serve as a potential drug for nonalcoholic fatty liver disease (NAFLD), especially in type 2 diabetes combined with NAFLD, and SIRT1 could be a therapeutic target of NAFLD.

The effects of dipeptidyl peptidase-4 inhibition on microvascular diabetes complications

We performed a review of the literature to determine whether the dipeptidyl peptidase-4 inhibitors (DPP4-I) may have the capability to directly and positively influence diabetic microvascular complications. The literature was scanned to identify experimental and clinical evidence that DPP4-I can ameliorate diabetic microangiopathy. We retrieved articles published between 1 January 1980 and 1 March 2014 in English-language peer-reviewed journals using the following terms: ("diabetes" OR "diabetic") AND ("retinopathy" OR "retinal" OR "nephropathy" OR "renal" OR "albuminuria" OR "microalbuminuria" OR "neuropathy" OR "ulcer" OR "wound" OR "bone marrow"); ("dipeptidyl peptidase-4" OR "dipeptidyl peptidase-IV" OR "DPP-4" OR "DPP-IV"); and ("inhibition" OR "inhibitor"). Experimentally, DPP4-I appears to improve inflammation, endothelial function, blood pressure, lipid metabolism, and bone marrow function. Several experimental studies report direct potential beneficial effects of DPP4-I on all microvascular diabetes-related complications. These drugs have the ability to act either directly or indirectly via improved glucose control, GLP-1 bioavailability, and modifying nonincretin substrates. Although preliminary clinical data support that DPP4-I therapy can protect from microangiopathy, insufficient evidence is available to conclude that this class of drugs directly prevents or decreases microangiopathy in humans independently from improved glucose control. Experimental findings and preliminary clinical data suggest that DPP4-I, in addition to improving metabolic control, have the potential to interfere with the onset and progression of diabetic microangiopathy. Further evidence is needed to confirm these effects in patients with diabetes.

Vildagliptin vs liraglutide as a second-line therapy switched from sitagliptin-based regimens in patients with type 2 diabetes: A randomized, parallel-group study

Introduction

A step-up strategy for dipeptidyl peptidase (DPP)-4 inhibitor-based regimens has not yet been established. In addition, similarities and differences between DPP-4 inhibitors and glucagon-like peptide (GLP)-1 receptor agonists remain to be elucidated in humans. We investigated the pleiotropic effects of vildagliptin vs liraglutide in patients with type 2 diabetes on sitagliptin-based regimens in an open-label, randomized, clinical trial.

Materials and Methods

A total of 122 patients with type 2 diabetes that was inadequately controlled by sitagliptin-based regimens were randomly assigned to either vildagliptin (50 mg, twice daily) or liraglutide treatment (0.9 mg, once daily) for 12 weeks. The primary outcomes were glycated hemoglobin and body mass index.

Results

Both vildagliptin and liraglutide significantly lowered glycated hemoglobin within 12 weeks after switching from sitagliptin, but liraglutide produced a greater reduction (−0.67 ± 0.12% vs −0.36 ± 0.53%). Liraglutide lowered body mass index, whereas vildagliptin did not affect body mass index. Vildagliptin lowered fasting C-peptide immunoreactivity, but liraglutide did not. Vildagliptin increased serum levels of adiponectin, arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid, whereas liraglutide had no effect on these levels. Quality of life, assessed using the diabetes treatment satisfaction questionnaire, was not impaired in either group. The most common adverse events were gastrointestinal symptoms, which occurred with similar frequencies in both groups.

Conclusions

Vildagliptin-mediated improvements in glycemic control did not correlate with indices for insulin secretion and insulin sensitivity. Switching from sitagliptin to liraglutide is useful in managing hyperglycemia and weight. Each agent exerts unique pleiotropic effects. This trial was registered with the University Hospital Medical Information Network Clinical Trials Registry (no. 000004953).

Patients with type 2 diabetes mellitus failing on oral agents and starting once daily insulin regimen; a small randomized study investigating effects of adding vildagliptin

Background

The addition of a DDP4-inhibitor to existing insulin therapy reduces HbA1c. However, no data exist about the addition of these agents at the beginning of insulin treatment in type 2 diabetes while this could especially be interesting because it is during this period that considerable residual beta cell function is still present. The benefit of such a strategy could be a lower insulin dose required for glycemic control. The hypothesis of our study was that adding a DPP4-inhibitor at the beginning of insulin treatment could lead to less exogenous insulin requirement, a reduction of hyperinsulinemia and side effects (hypoglycemia and weight gain), less glucose variability and improvement of insulin and glucagon dynamics during a mixed meal test.

Results

In this small clinical trial (trial registration NTR2022) 9 patients were randomized to receive vildagliptin and 6 to receive placebo in addition to start of once daily insulin treatment. Unfortunately, due to a difficult inclusion, the preset sample size of 40 patients could not be met. Median units of insulin at the end of the study was 47 U in the placebo group and 34 U in the vildagliptin group. Median glycemic variability (SD) at the end of study was 2.1 in the placebo group and 1.5 in the vildagliptin group. Median weight gain at the end of study was 3 kg in the placebo and 0.5 kg in the vildagliptin group. Occurrence of hypoglycemia was low in both groups. Insulin, C-peptide, glucose and glucagon levels were comparable during mixed meal tests.

Conclusions

This small randomized study did not have sufficient power to detect effects of the addition of vildagliptin to the start of once daily long-acting insulin. However in our opinion adding a DPP4-inhibitor, especially in this group remains a very interesting approach. This study could be used as a guidance for larger studies that are required to investigate the effects of this intervention on insulin requirements, glycemic variability, hypoglycemia and weight gain.

Electronic supplementary material

The online version of this article (doi:10.1186/1756-0500-7-579) contains supplementary material, which is available to authorized users.

The effect of alogliptin and pioglitazone combination therapy on various aspects of β-cell function in patients with recent-onset type 2 diabetes

OBJECTIVE

Type 2 diabetes mellitus (T2DM) management requires continuous treatment intensification due to progressive decline in β-cell function in insulin resistant individuals. Initial combination therapy of a dipeptidyl peptidase (DPP)-4 inhibitor with a thiazolidinedione (TZD) may be rational. We assessed the effects of the DPP4 inhibitor alogliptin (ALO) combined with the TZD pioglitazone (PIO), vs ALO monotherapy or placebo (PBO), on β-cell function and glycemic control in T2DM.

MATERIAL AND METHODS

A 16-week, two-center, randomized, double-blind, PBO-controlled, parallel-arm intervention study in 71 patients with well-controlled T2DM (age 59.1±6.3 years; A1C 6.7±0.1%) treated with metformin, sulfonylurea, or glinide monotherapy was conducted. Patients were treated with combined ALO 25 mg and PIO 30 mg daily or ALO 25 mg daily monotherapy or PBO. Main outcome measures included change in A1C and fasting plasma glucose (FPG) from baseline to week 16. In addition, change in β-cell function parameters obtained from standardized meal tests at baseline and at week 16 was measured.

RESULTS

ALO/PIO and ALO decreased A1C from baseline by 0.9±0.1 and 0.4±0.2% respectively (both P<0.001 vs PBO). FPG was decreased to a greater extent by ALO/PIO compared with ALO monotherapy (P<0.01). ALO/PIO treatment improved β-cell glucose sensitivity (vs PBO; P<0.001) and fasting secretory tone (vs PBO; P=0.001), while ALO monotherapy did not change β-cell function parameters. All treatments were well tolerated.

CONCLUSION

Short-term treatment with ALO/PIO or ALO improved glycemic control in well-controlled T2DM patients, but only combined ALO/PIO improved β-cell function. These data support that initial combination therapy with a DPP4 inhibitor and TZD to address multiple core defects in T2DM may be a sensible approach.

Does dipeptidyl peptidase-4 inhibition prevent the diabetogenic effects of glucocorticoids in men with the metabolic syndrome? A randomized controlled trial

OBJECTIVE

Anti-inflammatory glucocorticoid (GC) therapy often induces hyperglycemia due to insulin resistance and islet-cell dysfunction. Incretin-based therapies may preserve glucose tolerance and pancreatic islet-cell function. In this study, we hypothesized that concomitant administration of the dipeptidyl peptidase-4 inhibitor sitagliptin and prednisolone in men at high risk to develop type 2 diabetes could protect against the GC-induced diabetogenic effects.

DESIGN AND METHODS

Men with the metabolic syndrome but without diabetes received prednisolone 30  mg once daily plus sitagliptin 100  mg once daily (n=14), prednisolone (n=12) or sitagliptin alone (n=14) or placebo (n=12) for 14 days in a double-blind 2 × 2 randomized-controlled study. Glucose, insulin, C-peptide, and glucagon were measured in the fasted state and following a standardized mixed-meal test. β-cell function parameters were assessed both from a hyperglycemic-arginine clamp procedure and from the meal test. Insulin sensitivity (M-value) was measured by euglycemic clamp.

RESULTS

Prednisolone increased postprandial area under the curve (AUC)-glucose by 17% (P<0.001 vs placebo) and postprandial AUC-glucagon by 50% (P<0.001). Prednisolone reduced 1st and 2nd phase glucose-stimulated- and combined hyperglycemia-arginine-stimulated C-peptide secretion (all P ≤ 0.001). When sitagliptin was added, both clamp-measured β-cell function (P=NS for 1st and 2nd phase vs placebo) and postprandial hyperglucagonemia (P=NS vs placebo) remained unaffected. However, administration of sitagliptin could not prevent prednisolone-induced increment in postprandial glucose concentrations (P<0.001 vs placebo). M-value was not altered by any treatment.

CONCLUSION

Fourteen-day treatment with high-dose prednisolone impaired postprandial glucose metabolism in subjects with the metabolic syndrome. Concomitant treatment with sitagliptin improved various aspects of pancreatic islet-cell function, but did not prevent deterioration of glucose tolerance by GC treatment.

Cardiovascular actions of GLP-1 and incretin-based pharmacotherapy

Incretin-based therapy became recently available as antihyperglycemic treatment for patients with type 2 diabetes (T2DM). Incretin therapy comprises glucagon-like peptide receptor agonists (GLP-1RA) and dipeptidyl-peptidase 4 inhibitors (DPP4-I): these classes of drugs not only have the ability to reduce blood glucose, but also can exert several cardioprotective effects. They have been shown to positively influence some risk factors for cardiovascular disease (CVD), to improve endothelial function, and to directly affect cardiac function. For these reasons incretins are considered not only antidiabetic drugs, but also cardiovascular effective. The first clinical trials aimed to demonstrate the safety of DPP4 inhibitors have been recently published: their clinical significance will be discussed in light of the prior experimental findings.

The gut-renal axis: do incretin-based agents confer renoprotection in diabetes?

Diabetic nephropathy is the leading cause of end-stage renal disease worldwide, and is associated with a high risk of cardiovascular morbidity and mortality. Intensive control of glucose levels and blood pressure is currently the mainstay of both prevention and treatment of diabetic nephropathy. However, this strategy cannot fully prevent the development and progression of diabetic nephropathy, and an unmet need remains for additional novel therapies. The incretin-based agents--agonists of glucagon-like peptide 1 receptor (GLP-1R) and inhibitors of dipeptidyl peptidase 4 (DPP-4), an enzyme that degrades glucagon-like peptide 1--are novel blood-glucose-lowering drugs used in the treatment of type 2 diabetes mellitus (T2DM). Therapeutic agents from these two drug classes improve pancreatic islet function and induce extrapancreatic effects that ameliorate various phenotypic defects of T2DM that are beyond glucose control. Agonists of GLP-1R and inhibitors of DPP-4 reduce blood pressure, dyslipidaemia and inflammation, although only GLP-1R agonists decrease body weight. Both types of incretin-based agents inhibit renal tubular sodium reabsorption and decrease glomerular pressure as well as albuminuria in rodents and humans. In rodents, incretin-based therapies also prevent onset of the morphological abnormalities of diabetic nephropathy.

Independent glucose and weight-reducing effects of Liraglutide in a real-world population of type 2 diabetic outpatients

The GLP-1 receptor agonist Liraglutide is effective in reducing HbA1c in type 2 diabetic (T2D) patients. In addition, treatment with Liraglutide is associated with significant weight loss. In this study, we analyzed the inter-relationships between glycemic and weight effects of Liraglutide treatment in a population of type 2 diabetic outpatients. T2D patients initiating Liraglutide therapy since September 2010 to July 2012 at 3 outpatient clinics were enrolled and followed-up. We collected baseline information about anthropometric data, cardiovascular risk factors, diabetes duration, prevalence of complications and history of anti-diabetic medications. We collected HbA1c and body weight at baseline and every 4 months. A total of 166 patients were included, who were on average 56.6 ± 8.9 (mean ± SD) years old and had a baseline HbA1c of 8.7 ± 1.3 % and BMI 36.3 ± 6.4 kg/m(2). Mean follow-up was 9.4 ± 4.2 months (range 4-16). Patients lost on average 1.5 ± 1.3 % HbA1c and 4.0 ± 5.0 kg body weight. Most patients (73.5 %) improved HbA1c and loosed weight. Significant independent determinants of HbA1c drop were baseline HbA1c (r = 0.673; p < 0.001) and previous insulin therapy (r = -0.251; p < 0.001). The only independent determinant of weight loss was baseline BMI (r = 0.429; p < 0.001). Drop in HbA1c was unrelated to baseline BMI or weight loss. Weight loss was unrelated to baseline HbA1c or drop in HbA1c. Glycemic improvement and weight reduction obtained with Liraglutide treatment in T2D patients in a real-world setting are independent and possibly mediated by different mechanisms.