Blood pressure-lowering effects of GLP-1 receptor agonists exenatide and liraglutide: a meta-analysis of clinical trials

Practical combination therapy based on pathophysiology of type 2 diabetes

Type 2 diabetes is a complex, chronic, and progressive condition that often necessitates the use of multiple medications to achieve glycemic goals. Clinical guidelines generally recommend intensifying pharmacotherapy if glycemic goals are not achieved after 3 months of treatment. However, for many patients with type 2 diabetes, treatment intensification is delayed or does not occur. Initiating combination therapy early in the disease course has the potential to delay disease progression and improve patient outcomes. Guidelines generally provide a list of agents that may be used in combination regimens and emphasize individualization of treatment. The purpose of this review is to discuss the rationale for combination therapy, considering treatment effects on pathophysiologic aspects of type 2 diabetes and individual drug profiles. The combination of newer antidiabetes therapies with complementary mechanisms of action provides the opportunity to target multiple sites of tissue, organ, and cellular dysfunction.

The impact of insulin resistance on the kidney and vasculature

Insulin resistance is a systemic disorder that affects many organs and insulin-regulated pathways. The disorder is characterized by a reduced action of insulin despite increased insulin concentrations (hyperinsulinaemia). The effects of insulin on the kidney and vasculature differ in part from the effects on classical insulin target organs. Insulin causes vasodilation by enhancing endothelial nitric oxide production through activation of the phosphatidylinositol 3-kinase pathway. In insulin-resistant states, this pathway is impaired and the mitogen-activated protein kinase pathway stimulates vasoconstriction. The action of insulin on perivascular fat tissue and the subsequent effects on the vascular wall are not fully understood, but the hepatokine fetuin-A, which is released by fatty liver, might promote the proinflammatory effects of perivascular fat. The strong association of salt-sensitive arterial hypertension with insulin resistance indicates an involvement of the kidney in the insulin resistance syndrome. The insulin receptor is expressed on renal tubular cells and podocytes and insulin signalling has important roles in podocyte viability and tubular function. Renal sodium transport is preserved in insulin resistance and contributes to the salt-sensitivity of blood pressure in hyperinsulinaemia. Therapeutically, renal and vascular insulin resistance can be improved by an integrated holistic approach aimed at restoring overall insulin sensitivity and improving insulin signalling.

Glucagon-like peptide-1 receptor agonists favorably address all components of metabolic syndrome

Cardiovascular death is the leading cause of mortality for patients with type 2 diabetes mellitus. The etiology of cardiovascular disease in diabetes may be divided into hyperglycemia per se and factors operating through components of metabolic syndrome (MetS). Hyperglycemia causes direct injury to vascular endothelium and possibly on cardiac myocytes. MetS is a cluster of risk factors like obesity, hyperglycemia, hypertension and dyslipidemia. The incidence of this syndrome is rising globally. Glucagon-like peptide-1 receptor agonists (GLP-1RA) are a group of drugs, which address all components of this syndrome favorably. Experimental evidence suggests that they have favorable actions on myocardium as well. Several compounds belonging to GLP-1RA class are in market now and a large number awaiting their entry. Although, originally this class of drugs emerged as a treatment for type 2 diabetes mellitus, more recent data generated revealed beneficial effects on multiple metabolic parameters. We have studied literature published between 2000 and 2016 to look into effects of GLP-1RA on components of MetS. Results from recently concluded clinical trials suggest that some of the molecules in this class may have favorable effects on cardiovascular outcome.

Cardiovascular safety of therapies for type 2 diabetes

INTRODUCTION

Dipeptidyl peptidase-4 (DPP4) inhibitors, glucagon-like peptide-1 (GLP-1) analogs and sodium-glucose cotransporter 2 (SGLT2) inhibitors are relatively new therapies for the treatment of type 2 diabetes mellitus. Given the high prevalence of cardiovascular complications in patients with type 2 diabetes and recent concerns questioning CV safety of newer antidiabetic medications, cardiovascular safety of these medications requires evaluation. Areas covered: Cardiovascular effects of these drug classes from preclinical and clinical data as well as non-cardiovascular safety issues are delineated from literature searches covering the last decade and up to June 2016. Major clinical trials assessing the cardiovascular safety of GLP-1 agonists (ELIXA and LEADER), DPP-4 inhibitors (SAVOR-TIMI 53, EXAMINE, and TECOS) and SGLT2 inhibitors (EMPA-REG OUTCOME) are reviewed and interpreted. Expert opinion: Based on review of the present evidence, these 3 classes of antihyperglycemic therapies have acceptably safe CV safety profiles for patients with type 2 diabetes. The latest evidence from LEADER and EMPA-REG OUTCOME trials indicate that liraglutide and empagliflozin have cardiovascular benefits that may prove to be of clinical importance in the management of type 2 DM.

Effects of dipeptidyl peptidase-4 inhibitors on blood pressure in patients with type 2 diabetes: A systematic review and meta-analysis

This review was undertaken to assess the effects of dipeptidyl peptidase-4 (DPP-4) inhibitors on blood pressure (BP) in patients with type 2 diabetes (T2DM). We searched three main databases (PubMed, Web of Science, and Scopus) for relevant articles. Randomized controlled trials which reported BP changes from baseline to study endpoint in patients with T2DM receiving treatment of DPP-4 inhibitors were included for analysis. Random effects models were used to measure the mean differences with 95% confidence intervals (CIs). Fifteen trials involving 5636 participants were identified. When compared with placebo or nontreatment, DPP-4 inhibitors achieved greater reductions for both SBP (mean difference, -3.04  mmHg; 95% CI, -4.37 to -1.72; P < 0.00001) and DBP (mean difference, -1.47  mmHg; 95% CI, -1.79 to -1.15; P < 0.00001). But the BP-lowering effects of sodium-glucose cotransporter 2 inhibitors were more significant than those of DPP-4 inhibitors for both SBP (mean difference, 4.44  mmHg; 95% CI, 2.67-6.22; P < 0.00001) and DBP (mean difference, 2.15  mmHg; 95% CI, 1.08-3.21; P < 0.00001). No significant differences in BP changes were shown between DPP-4 inhibitors with other antidiabetic agents including glucagon-like peptide 1 receptor agonists, pioglitazone, sulphonylureas, metformin, and α-glucosidase inhibitors. DPP-4 inhibitors may exert modest BP-lowering effects compared with placebo or nontreatment for patients with T2DM, but no significant BP improvement was seen with this drug class when compared with other antidiabetic medications.

SGLT2 Inhibition and cardiovascular events: why did EMPA-REG Outcomes surprise and what were the likely mechanisms?

While the modest reduction in the primary composite outcome of myocardial infarction, stroke or cardiovascular death in the EMPA-REG Outcomes trial was welcome, the 30-40% reductions in heart failure hospitalisation (HFH) and cardiovascular and all-cause deaths in patients treated with empagliflozin were highly impressive and unexpected. In this review, we discuss briefly why cardiovascular endpoint trials for new diabetes agents are required and describe the results of the first four such trials to have reported, as a precursor to understanding why the EMPA-REG Outcomes results came as a surprise. Thereafter, we discuss potential mechanisms that could explain the EMPA-REG Outcomes results, concentrating on non-atherothrombotic effects. We suggest that the main driver of benefit may derive from the specific effects of sodium-glucose linked transporter-2 (SGLT2) inhibition on renal sodium and glucose handling, leading to both diuresis and improvements in diabetes-related maladaptive renal arteriolar responses. These haemodynamic and renal effects are likely to be beneficial in patients with clinical or subclinical cardiac dysfunction. The net result of these processes, we argue, is an improvement in cardiac systolic and diastolic function and, thereby, a lower risk of HFH and sudden cardiac death. We also discuss whether other drugs in this class are likely to show similar cardiovascular benefits. Finally, areas for future research are suggested to better understand the relevant mechanisms and to identify other groups who may benefit from SGLT2 inhibitor therapy.

SGLT2 inhibitors or GLP-1 receptor agonists as second-line therapy in type 2 diabetes: patient selection and perspectives

Controversy exists regarding the selection of second-line therapy for patients with type 2 diabetes mellitus (T2DM) who are unable to achieve glycemic control with metformin therapy alone. Newer pharmacologic treatments for T2DM include glucagon-like peptide-1 receptor agonists and sodium–glucose cotransporter 2 inhibitors. Both the classes of medication are efficacious, exhibit positive effects on weight, and are associated with minimal risk of hypoglycemia. The purpose of this review is to compare the clinical trial and real-world effectiveness data of glucagon-like peptide-1 receptor agonists versus sodium–glucose cotransporter 2 inhibitors related to A1c reduction, weight loss, cost-effectiveness, cardiovascular outcomes, and safety in patients with T2DM. This review summarizes comparative evidence for providers who are determining which of the two classes may be the most appropriate for a specific patient.

Cardiovascular Effects of Glucagon-Like Peptide-1 Receptor Agonists

Glucagon-like peptide-1 (GLP-1) is a member of the proglucagon incretin family, and GLP-1 receptor agonists (RAs) have been introduced as a new class of antidiabetic medications in the past decade. The benefits of GLP-1 RAs are derived from their pleiotropic effects, which include glucose-dependent insulin secretion, suppressed glucagon secretion, and reduced appetite. Moreover, GLP-1 RAs also exert beneficial roles on multiple organ systems in which the GLP-1 receptors exist, including the cardiovascular system. Cardiovascular effects of GLP-1 RAs have been of great interest since the burden from cardiovascular diseases (CVD) has been unbearably increasing in a diabetic population worldwide, despite strict glycemic control and advanced therapeutic techniques to treat CVD. Preclinical studies have already demonstrated the beneficial effects of GLP-1 on myocardium and vascular endothelium, and many clinical studies evaluating changes in surrogate markers of CVD have suggested potential benefits from the use of GLP-1 RAs. Data from numerous clinical trials primarily evaluating the antihyperglycemic effects of multiple GLP-1 RAs have also revealed that changes in most CVD risk markers reported as secondary outcomes have been in favor of GLP-1 RAs treatment. However, to date, there is only one randomized clinical trial of GLP-1 RAs (the ELIXA study) evaluating major cardiovascular events as their primary outcomes, and in this study, a neutral cardiovascular effect of lixisenatide was observed in high-risk diabetic subjects. Therefore, the results of ongoing CVD outcome trials with the use of GLP-1 RAs should be awaited to elucidate the translation of benefits previously seen in CVD risk marker studies into large clinical trials with primary cardiovascular outcomes.

Combination therapy of SGLT2 inhibitors with incretin-based therapies for the treatment of type 2 diabetes mellitus: Effects and mechanisms of action

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide; its pathogenesis is multifactorial and its progressive nature often necessitates a combination therapy with multiple antihyperglycemic agents. Sodium glucose cotransporter 2 (SGLT2) inhibitors and the incretin-based therapies - dipeptidyl peptidase 4(DPP-4) inhibitors and glucagon-like peptide 1 (GLP-1) receptor agonists - were introduced for the treatment of T2DM within the last decade. Evidence of the beneficial effects of these antihyperglycemic agents on micro- and macrovascular complications have started to emerge, which will become important in individualizing different combinations of antihyperglycemic agents to different patient populations. We review here the mechanisms of action, glycemic and cardiovascular effects of SGLT2 inhibitors and incretin-based therapies and their combination in the treatment of T2DM.

Clinically and pharmacologically relevant interactions of antidiabetic drugs

Patients with type 2 diabetes mellitus often require multifactorial pharmacological treatment due to different comorbidities. An increasing number of concomitantly taken medications elevate the risk of the patient experiencing adverse drug effects or drug interactions. Drug interactions can be divided into pharmacokinetic and pharmacodynamic interactions affecting cytochrome (CYP) enzymes, absorption properties, transporter activities and receptor affinities. Furthermore, nutrition, herbal supplements, patient's age and gender are of clinical importance. Relevant drug interactions are predominantly related to sulfonylureas, thiazolidinediones and glinides. Although metformin has a very low interaction potential, caution is advised when drugs that impair renal function are used concomitantly. With the exception of saxagliptin, dipeptidyl peptidase-4 (DPP-4) inhibitors also show a low interaction potential, but all drugs affecting the drug transporter P-glycoprotein should be used with caution. Incretin mimetics and sodium-glucose cotransporter-2 (SGLT-2) inhibitors comprise a very low interaction potential and are therefore recommended as an ideal combination partner from the clinical-pharmacologic point of view.

Sodium-glucose cotransporter 2 inhibitors and cardiovascular outcomes

Type 2 diabetes mellitus (T2DM) is associated with an elevated risk of cardiovascular (CV) morbidity and mortality. Furthermore, many patients with T2DM have comorbidities that are risk factors for CV disease. While intensive glucose control reduces the risk of diabetic microvascular complications, its relationship to CV outcomes remains unclear. Consequently, the management of CV risk factors in patients with T2DM is complex, and factors other than blood glucose must be considered. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, a class of oral glucose-lowering agents, are associated with reductions in blood pressure and body weight, in addition to decreasing hyperglycemia, and therefore have the potential to reduce CV risk in patients with T2DM. The clinical trial results of SGLT2 inhibitors regarding CV safety and outcomes are discussed, including data from the recently published EMPA-REG OUTCOME study. This trial was the first dedicated CV outcomes study to demonstrate that a glucose-lowering agent lowered CV mortality and all-cause mortality, and reduced hospitalization for heart failure in patients with T2DM at high risk of CV events.

A Multifactorial Approach to Reduce Cardiovascular Disease in Type 2 Diabetes Mellitus: Now More Than Ever

Managing cardiovascular (CV) risk is an important part of caring for patients with type 2 diabetes mellitus, as the disease itself confers CV risk. Many CV risk factors (such as hypertension, dyslipidemia, and obesity) have been found to be more common among individuals with diabetes than in the general population. A growing body of evidence provides guidance for clinicians on how to balance control of hyperglycemia with management of these risk factors. Newer classes of antihyperglycemic agents have been associated with beneficial effects on several CV risk factors; several studies evaluating the effect of these newer diabetic medications on CV outcomes have been published, and several more are in progress. While evidence continues to unfold about the benefits of risk factor control in patients with type 1 diabetes mellitus, this article reviews evidence related to risk-factor control in patients with type 2 diabetes mellitus as well as recent findings on the effect of newer drug classes on CV risk factors and outcomes. Favorably altering CV risk factors appears to improve outcomes, and is more important now than ever before.

Cardiovascular Effects of Incretin-Based Therapies

The incretin-based therapies, dipeptidyl peptidase-4 (DPP4) inhibitors and glucagon-like peptide-1 (GLP-1) analogs, are important new classes of therapy for type 2 diabetes mellitus (T2DM). These agents prolong the action of the incretin hormones, GLP-1 and glucose-dependent insulinotropic polypeptide (GIP), by inhibiting their breakdown. The incretin hormones improve glycemic control in T2DM by increasing insulin secretion and suppressing glucagon levels. The cardiovascular (CV) effects of the incretin-based therapies have been of substantial interest since 2008, when the US Food and Drug Administration began to require that all new therapies for diabetes undergo rigorous assessment of CV safety through large-scale CV outcome trials. This article reviews the most recent CV outcome trials of the DPP-4 inhibitors (SAVOR-TIMI 53, EXAMINE, and TECOS) as evidence that the incretin-based therapies have acceptable CV safety profiles for patients with T2DM. The studies differ with regard to patient population, trial duration, and heart failure outcomes but show similar findings for CV death, nonfatal myocardial infarction, and stroke, as well as hospitalization for unstable angina.

Glucagon-Like Peptide-1 Receptor Agonists for Type 2 Diabetes: A Clinical Update of Safety and Efficacy

INTRODUCTION

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly being used for the treatment of type 2 diabetes mellitus, but consideration of benefits and potential adverse events is required. This review examines the state of glycemic control, weight loss, blood pressure, and tolerability, as well as the current debate about the safety of GLP-1 RAs, including risk of pancreatitis, pancreatic cancer, and thyroid cancer.

METHODS

A MEDLINE search (2010-2015) identified publications that discussed longer-acting GLP-1 RAs. Search terms included GLP-1 receptor agonists, liraglutide, exenatide, lixisenatide, semaglutide, dulaglutide, albiglutide, efficacy, safety, pancreatitis, pancreatic cancer, and thyroid cancer. Abstracts from the American Diabetes Association, European Association for the Study of Diabetes, and American Association of Clinical Endocrinologists from 2010 to 2015 were also searched. Efficacy and safety studies, pooled analyses, and meta-analyses were prioritized.

RESULTS

Research has confirmed that GLP-1 RAs provide robust glycemic control, weight loss, and blood pressure re-duction. Current studies do not prove increased risk of pancreatitis, pancreatic cancer, or thyroid cancer but more trials are needed since publications that indicate safety or suggest increased risk have methodological flaws that prevent firm conclusions to be drawn about these rare, long-term events.

CONCLUSION

GLP-1 RA therapy in the context of individualized, patient-centered care continues to be supported by current literature. GLP-1 RA therapy provides robust glycemic control, blood pressure reduction, and weight loss, but studies are still needed to address concerns about tolerability and safety, including pancreatitis and cancer.

One-year treatment with liraglutide improved renal function in patients with type 2 diabetes: a pilot prospective study

Unlike GLP-1, liraglutide is not cleared by the glomerulus and its pharmacokinetic is not altered in patients with mild renal impairment. The aim of our study was to analyze the effects of liraglutide on renal function in patients with type 2 diabetes. A twelve-month longitudinal prospective post-marketing study was performed. According to eGFR (estimated glomerular filtration rate) calculated with CKD-EPI equation, 84 consecutive patients were divided in Group A (eGFR > 90 ml/min) and Group B (eGFR < 90 ml/min). BMI, glucose, HbA1c, serum creatinine, microalbuminuria, and eGFR were evaluated at baseline and after 12 months of treatment. A reduction in fasting plasma glucose (p < 0.01), HbA1c (p < 0.003), BMI (p < 0.01), and systolic (p < 0.01) and diastolic blood pressure (p < 0.006) was recorded irrespective of eGFR category. Concerning renal function, creatinine levels had a trend to decrease in both groups. eGFR did not change in Group A, while it increased in Group B (p < 0.05) independently from the concomitant changes of other parameters. Moreover, seven out of 41 patients of Group B had increased eGFR levels which reached the normal values (>90 ml/min). At baseline, five patients had pathological microalbuminuria, but at 12 months three of them returned to normal albuminuria (p < 0.006). Total microalbuminuria levels improved in both groups (p < 0.02). According to preliminary data in animals, our study shows that liraglutide is effective in preserving eGFR in diabetic patients, increasing it in those with reduced renal function. This was associated with a decrease of frequency of patients positive to microalbuminuria. Further studies are needed to confirm these data.

Liraglutide Improves Glycemic and Blood Pressure Control and Ameliorates Progression of Left Ventricular Hypertrophy in Patients with Type 2 Diabetes Mellitus on Peritoneal Dialysis

Diabetes mellitus (DM) is a multifactorial disease associated with cardiovascular complications. Patients undergoing peritoneal dialysis also experience an increased incidence of cardiovascular disease. To prevent progression of cardiovascular complications in DM patients, glycemic control is important. In this study, we examined the efficacy and safety of the glucagon-like peptide analog liraglutide for treating type 2 diabetes patients undergoing peritoneal dialysis. Sixteen type 2 diabetes patients on peritoneal dialysis were enrolled. Before liraglutide initiation, 11 patients were on insulin therapy, three were on oral antidiabetic agents, and two were on diet therapy. Of the 16 patients, 12 had switched to liraglutide because of severe hypoglycemia and four because of hyperglycemia. Echocardiography was performed at baseline and 12 months after liraglutide initiation. Hemoglobin A1c, glycosylated albumin, and fasting/postprandial glucose levels gradually decreased after liraglutide initiation. After 6 and 12 months of treatment, postprandial glucose levels showed a significant difference from baseline. Moreover, the mean daily glucose level and glycemic fluctuations decreased. Systolic blood pressure upon waking also decreased. In addition, after 12 months, left ventricular mass index (LVMI) decreased and left ventricular ejection fraction increased. Changes in LVMI positively correlated with morning systolic blood pressure and fasting glucose levels. One patient restarted insulin because of anorexia but severe hypoglycemia was not observed. These findings suggest that liraglutide therapy in type 2 diabetes patients undergoing peritoneal dialysis is safe and effective for decreasing glucose levels, glycemic fluctuations, and blood pressure, apart from improving left ventricular function.

Advances in understanding relationship between GLP-1 based drugs and the kidney

The drugs based on glucagon-like peptide-1 (GLP-1) not only lower urinary protein, but also increase urine sodium excretion and improve the pathological changes of kidney disease. However, the mechanism is not very clear and may be associated with atrial natriuretic peptide, renin angiotensin axis, and oxidative stress. This review focuses on the progress in understanding the relationship between GLP-1 and the kidney.

Impact of GLP-1 receptor agonists on blood pressure, heart rate and hypertension among patients with type 2 diabetes: A systematic review and network meta-analysis

AIMS

To evaluate current evidence of glucagon-like peptide-1 receptor agonists (GLP-1RAs) on blood pressure, heart rate, and hypertension in patients with type 2 diabetes.

METHODS

Medline, Embase, the Cochrane library, and the website www.clinicaltrials.gov were searched on April 5th, 2014. Randomized-controlled trials with available data were included if they compared GLP-1RAs with placebo and traditional antidiabetic drugs in patients with type 2 diabetes with duration ≥ 12 weeks. Weighted mean difference for blood pressure and heart rate, odds ratio (OR) for hypertension were calculated by random-effect model. Network meta-analysis was performed to supplement direct comparisons.

RESULTS

Sixty trials with 14 treatments were included. Compared with placebo, insulin, and sulfonylureas, GLP-1RAs decreased systolic blood pressure with range from -1.84 mmHg (95% CI: -3.48 to -0.20) to -4.60 mmHg (95% CI: -7.18 to -2.03). Compared with placebo, a reduction in diastolic blood pressure was detected significantly only for exenatide-10 μg-twice-daily (-1.08 mmHg, 95% CI: -1.78 to -0.33). Exenatide (2 mg once weekly), liraglutide 1.2 mg once daily), and liraglutide (1.8 mg once daily) increased heart rate by 3.35 (95% CI: 1.23-5.50), 2.06 (95% CI: 0.43, 3.74), and 2.35 (95% CI: 0.94-3.76) beats/min versus placebo. This effect was evident compared with active control (range: 2.22-3.62). No significant association between incident hypertension and GLP-1RAs was detected, except for the association between exenatide-10 μg-twice-daily and sulfonylureas (OR, 0.40, 95% CI: 0.16, 0.82).

CONCLUSIONS

GLP-1RAs were associated with modest reduction on blood pressure, a slight increase in heart rate, yet no significant association with hypertension. Further investigation to explore mechanisms is warranted.

Effectiveness of Liraglutide in Type II Diabetes Mellitus Management: Experience in Emirati Patients

OBJECTIVE

To measure effectiveness of liraglutide in reducing glycated hemoglobin (HbA1C), weight, and systolic blood pressure (SBP) in Emirati patients.

DESIGN

A retrospective cohort study.

SETTING

Endocrinology clinic in a 300-bed military hospital.

PATIENTS

A total of 152 patients who qualified for liraglutide between September 21, 2012, (first patient visit) and May 5, 2014 (last patient visit).

METHODS

Team collected demographic and clinical data using a standard form. Data keeper performed univariate analyses to measure the effect of liraglutide in reducing the three outcomes of interest; namely, HbA1C, weight, and SBP.

RESULTS

One hundred patients had at least the first visit in the clinic and 98 patients came for a second follow-up visit while on the medication. Adherence of clinicians to the internal criteria for prescribing liraglutide was 92%. Patients' ages were 47.9 ± 11.7 years. Male-to-female ratio was almost 1:1. Overall, in the paired analyses, HbA1C decreased from first to second visits (8.7 ± 1.9 vs. 7.6 ± 1.8, P > 0.0001) and remained unchanged in subsequent visits (eg, in visit 3, HbA1C was 7.4 ± 1.8). Patients lost an average of 1.3 kg between the first and second visits (99.3 ± 19.3 vs. 98.0 ± 19.5, P = 0.0003). The reduction in SBP between visits 1 and 2 was less (130.9 ± 15.8 vs. 129.9 ± 16.5, P = 0.5896). ANOVA yielded a significant reduction in HbA1C at 4 months and 6 months (P values < 0.05). SBP dropped by about 3.6 mmHg and weight by about 2.3 kg (P values > 0.05).

CONCLUSIONS

Liraglutide is effective in reducing HbA1C, weight, and to a lesser extent, SBP in Emirati patients.

Incretin-based therapies for obesity treatment

Currently, obesity and its associated complications are considered major public health problems worldwide. Because the causes are multifactorial and complex, different treatment methods are used, which include diet and exercise, as well as the use of drugs, although they can have adverse side effects. A new target for the treatment of obesity may be the incretin system, which consists of hormones that seem to contribute to weight loss. In this sense, some studies have shown a relationship between weight loss and drugs related to incretin system, including glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors. The objective of this review is to summarize the association between the incretin system and obesity treatment.

Exenatide twice daily: a review of its use in the management of patients with type 2 diabetes mellitus

Exenatide, administered subcutaneously twice daily (Byetta(®)), is a synthetic version of the natural peptide exendin-4, which is a glucagon-like peptide-1 (GLP-1) receptor agonist (incretin mimetic). Exenatide binds to the GLP-1 receptor with the same affinity as GLP-1, but has a much longer half-life, since it is not degraded by the enzyme dipeptidyl peptidase-4. Exenatide twice daily enhances glucose-dependent insulin secretion, suppresses inappropriately elevated glucagon secretion, slows gastric emptying and reduces caloric intake. In well-designed clinical trials, adjunctive subcutaneous exenatide 5 or 10 μg twice daily for 16-52 weeks significantly and dose-dependently improved glycaemic control and reduced mean body weight compared with placebo in patients with type 2 diabetes inadequately controlled with oral antihyperglycaemic drugs (OADs) and/or basal insulin. The improvements in glycaemic control and reductions in body weight were stably maintained during long-term therapy (up to 3.5 years). The efficacy of adjunctive exenatide twice daily was generally similar to that of basal, prandial or biphasic insulin, sulfonylureas, rosiglitazone and lixisenatide, and less than that of liraglutide, taspoglutide or exenatide once weekly with respect to reductions in glycated haemoglobin. Exenatide twice daily was generally well tolerated; mild to moderate nausea and vomiting, which decreased with time on therapy, were the most common adverse events. In patients not receiving concomitant sulfonylureas or insulin, the incidence of hypoglycaemia was low; when it did occur, it was generally mild in severity. Thus, adjunctive exenatide twice daily is a valuable option in the treatment of type 2 diabetes inadequately controlled with OADs and/or basal insulin.

Dipeptidyl peptidase-4 inhibitors in progressive kidney disease

PURPOSE OF REVIEW

Dipeptidyl peptidase-4 (DPP-4) inhibitors are incretin-based drugs approved for the treatment of type 2 diabetes. The main action of DPP-4 inhibitors is to increase the level of incretin hormones such as glucagon-like peptide-1 (GLP-1), thereby stimulating insulin secretion from pancreatic β cells. Recently emerging evidence suggests the pleiotropic extrapancreatic function of GLP-1 or DPP-4 inhibitors, including kidney and cardiovascular protection. Here, we review the effects of DPP-4 inhibitors on progressive kidney disease such as diabetic nephropathy from a therapeutic point of view.

RECENT FINDINGS

A growing number of studies in animal models and human diseases have shown that DPP-4 inhibition ameliorates kidney disease by a process independent of glucose lowering. Possible mechanisms underlying such protective properties include the facilitation of natriuresis and reduction of blood pressure, and also local effects of the reduction of oxidative stress, inflammation and improvement of endothelial function in the kidney. DPP-4 inhibitors may also restore other DPP-4 substrates which have proven renal effects.

SUMMARY

Treatment of diabetes with DPP-4 inhibitors is likely to involve a variety of extrapancreatic effects including renal protection. Such pleiotropic action of DPP-4 inhibitors might occur by both incretin-dependent and incretin-independent mechanisms. Conclusive evidence is needed to translate the favorable results from animal models to humans.

Cardiovascular Risk in Diabetes Mellitus: Complication of the Disease or of Antihyperglycemic Medications

Cardiovascular disease is the principal complication and the leading cause of death for patients with diabetes (DM). The efficacy of antihyperglycemic treatments on cardiovascular disease risk remains uncertain. Cardiovascular risk factors are affected by antihyperglycemic medications, as are many intermediate markers of cardiovascular disease. Here we summarize the evidence assessing the cardiovascular effects of antihyperglycemic medications with regard to risk factors, intermediate markers of disease, and clinical outcomes.

Blood pressure-lowering effects of incretin-based diabetes therapies

Glucagon-like peptide-1 receptor (GLP-1) agonists and dipeptidyl-peptidase-4 (DPP-4) inhibitors are therapies that are used to treat hyperglycemia in patients with type 2 diabetes mellitus. Although both of these medication types primarily lower prandial and fasting blood glucose levels by enhanced GLP-1 receptor signalling, they have distinct mechanisms of action. Whereas DPP-4 inhibitors boost patient levels of endogenously produced GLP-1 (and glucose-dependent insulinotropic peptide) by preventing its metabolism by DPP-4 enzymatic activity, GLP-1 receptor agonists are either synthetic analogues of human GLP-1 or exendin-4 based molecules. They are tailored to resist hydrolysis by DPP-4 activity and to provide longer durability in the circulation compared with native GLP-1. Several roles for incretin-based diabetes therapies beyond the endocrine pancreas and their glycemic-lowering properties have now been described, including attenuation of cardiac myocyte injury and reduction in post-ischemic infarction size after cardiovascular insult. Favourable outcomes have also been observed on systolic blood pressure reduction, postprandial intestinal lipoprotein metabolism, endothelial cell function, modulation of innate immune-mediated inflammation and surrogate markers of renal function. As hypertension is an independent risk factor for premature death in patients with type 2 diabetes, potential favourable extrapancreatic actions, particularly within the heart, blood vessels and kidney, for this drug class are of considerable clinical interest. Herein, we highlight and provide critical appraisal of the clinical data supporting the antihypertensive effects of GLP-1 receptor agonists and DPP-4 inhibitors and link possible mechanisms of action to clinical outcomes reported for this drug class.

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.

Liraglutide effect in reducing HbA1c and weight in Arab population with type2 diabetes, a prospective observational trial

Background

The pathophysiology of type2 diabetes differs between different ethnic groups. Asians develop type2 diabetes at younger age, lower body mass index, and in relatively short time. Not only that, some ethnicities have different responses and dosing regimens to different classes of anti-diabetic agents. Data from Japanese population showed that the optimal doses of liraglutide used are smaller than other population and that weight loss is not as effective as seen in Caucasians.

Methods

We aimed to assess liraglutide efficacy in reducing weight and HbA1c in Arab population when used as add on to other anti-diabetic agents. We prospectively followed patients who were recruited to treatment with liraglutide for a 6 months period; at the start of the study we checked patients’ demographics, weight, blood pressure, fasting blood glucose, HbA1c, lipid panel, LFTs and creatinine. Patients were checked at 3 months and at the end of the study at 6 months.

Results

There was a significant reduction in weight at 3 and 6 months from a mean weight of 96.01 ± 19.2 kg to (94.8 ± 20 kg with (P < 0.001)) and 94.5 ± 19 kg with (p < 0.001) respectively. Mean HbA1c at baseline was 8.3 ± 1.7 % dropped to 7.7 ± 1.4 % (p < 0.001) at 3 months, and 7.6 + 1.6 % (p < 0.001) at 6 months.

Conclusions

Liraglutide is effective in reducing weight, HbA1c as well as other metabolic parameters in Arab population with type2 diabetes.

Trial registration

The trial is approved and registered with the Institutional Ethical Committee Board (Dubai Health Authority Medical Research Committee) under registration Number (MRC-08/2013_03).

Liraglutide improves hypertension and metabolic perturbation in a rat model of polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, with a prevalence of 5–8%. Type 2 diabetes and cardiovascular disease (CVD) are its long-term complications. Targeted therapies addressing both these complications together are lacking. Glucagon like peptide-1 (GLP-1) agonists that are used to treat type 2 diabetes mellitus have beneficial effects on the cardiovascular system. Hence we hypothesized that a GLP-1 agonist would improve both cardiovascular and metabolic outcomes in PCOS. To test this hypothesis, we used an established rat model of PCOS. Prepubertal female Sprague Dawley rats were sham-implanted or implanted s.c. with dihydrotestosterone (DHT) pellets (90 day release; 83μg/day). At 12 wks of age, sham implanted rats received saline injections and the DHT treated animals were administered either saline or liraglutide (0.2mg/kg s.c twice daily) for 4 weeks. Subgroups of rats were implanted with telemeters between 12-13 weeks of age to monitor blood pressure. DHT implanted rats had irregular estrus cycles and were significantly heavier than the control females at 12 weeks (mean± SEM 251.9±3.4 vs 216.8±3.4 respectively; p<0.05) and 4 weeks of treatment with liraglutide in DHT treated rats significantly decreased body weight (mean± SEM 294.75 ±3.2 in DHT+ saline vs 276.25±2.7 in DHT+ liraglutide group respectively; p<0.01). Liraglutide treatment in the DHT implanted rats significantly improved glucose excursion during oral glucose tolerance test (area under the curve: DHT+ saline 28674±310 vs 24990± 420 in DHT +liraglutide p <0.01). DHT rats were hypertensive and liraglutide treatment significantly improved mean arterial pressure. These results suggest that GLP-1 treatment could improve DHT–induced metabolic and blood pressure deficits associated with PCOS.

Obesity and insulin resistance in resistant hypertension: implications for the kidney

There is recognition that the obesity epidemic contributes substantially to the increasing incidence of CKD and resistant hypertension (HTN). The mechanisms by which obesity promotes resistance are an area of active interest and intense investigation. It is thought that increases in visceral adiposity lead to a proinflammatory, pro-oxidative milieu that promote resistance to the metabolic actions of insulin. This resistance to insulin at the level of skeletal muscle tissue impairs glucose disposal/utilization through actions on the endothelium that include vascular rarefaction, reductions in vascular relaxation, and vascular remodeling. Insulin resistance derived from increased adipose tissue and obesity has system-wide implications for other tissue beds such as the kidney that affects blood pressure regulation. The additional autocrine and paracrine activities of adipose tissue contribute to inappropriate activation of the renin-angiotensin-aldosterone system and the sympathetic nervous system that promote kidney microvascular remodeling, stiffness, and sodium (Na(+)) retention that in turn promote HTN and in the CKD patient, resistance. In this review, we will summarize the important mechanisms that link obesity to CKD as they relate to resistant HTN.

Beat it early: putative renoprotective haemodynamic effects of oral hypoglycaemic agents

Diabetic kidney disease represents a considerable burden; around one-third of patients with type 2 diabetes develop chronic kidney disease. In health, the kidneys play an important role in the regulation of glucose homeostasis via glucose utilization, gluconeogenesis and glucose reabsorption. In patients with diabetes, renal glucose homeostasis is significantly altered with an increase in both gluconeogenesis and renal tubular reabsorption of glucose. Environmental factors, both metabolic (hyperglycaemia, obesity and dyslipidaemia) and haemodynamic, together with a genetic susceptibility, lead to the activation of pro-oxidative, pro-inflammatory and pro-fibrotic pathways resulting in kidney damage. Hyperfiltration and its haemodynamic-driven insult to the kidney glomeruli is an important player in proteinuria and progression of kidney disease towards end-stage renal failure. Control of glycaemia and blood pressure are the mainstays to prevent kidney damage and slow its progression. There is emerging evidence that some hypoglycaemic agents may have renoprotective effects which are independent of their glucose-lowering effects. Sodium-glucose co-transporter-2 (SGLT-2) inhibitors may exert a renoprotective effect by a number of mechanisms including restoring the tubuloglomerular feedback mechanism and lowering glomerular hyperfiltration, reducing inflammatory and fibrotic markers induced by hyperglycaemia thus limiting renal damage. Simultaneous use of an SGLT-2 inhibitor and blockade of the renin-angiotensin-aldosterone system may be a strategy to slow progression of diabetic nephropathy more than either drug alone. The use of dipeptidyl peptidase-4 inhibitors and glucagon-like peptide 1 receptor agonists may exert a renoprotective effect by reducing inflammation, fibrosis and blood pressure. Given the burden of diabetic kidney disease, any additional renoprotective benefit with hypoglycaemic therapy is to be welcomed. Large randomized controlled trials are currently underway investigating if these new anti-diabetic agents can provide renoprotection in diabetes.

Cardiometabolic Effects of a New Class of Antidiabetic Agents

PURPOSE

Within the past decade, many new classes of drugs have received approval from the US Food and Drug Administration for treatment of type 2 diabetes mellitus, including glucagon-like peptide-1agonists, dipeptidyl peptidase-4 inhibitors, and the sodium-glucose cotransporter-2 inhibitors. Many trials have been performed, and several more are currently ongoing to evaluate these drugs. This review addresses the broad therapeutic and pleiotropic effects of these drugs. The review also discusses the role of these drugs in the treatment paradigm for type 2 diabetes and identifies patients who would be suitable candidates for treatment with these drugs.

METHODS

In this comprehensive evidence-based review, the following databases were searched from 1990 to the present: PubMed/MEDLINE, Scopus, CINAHL, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Portal, and the American Diabetes Association and European Association for the Study of Diabetes abstract databases. Randomized clinical trials (RCTs) were only included for the main therapeutic and cardiovascular (CV) effects of these drug classes. For pleiotropic effects, RCTs were included unless no RCTs exist, in which case other studies as specified in the detailed Methods section were included.

FINDINGS

All 3 drug classes are effective in lowering hemoglobin A1c between 0.4% and 1.4%, depending on the drug class and population selected. These drug classes have beneficial effects on CV risk factors, such as weight, lipids, and blood pressure, in addition to lowering blood glucose levels. The CV tolerability of some drugs has been evaluated and found to be neutral; however, most trials are currently ongoing to assess CV tolerability. There are no concrete guidelines to determine where these drugs fit in the diabetes management paradigm, and there are ongoing trials to determine the best combination drug with metformin.

IMPLICATIONS

These 3 drug classes will potentially increase the armamentarium against hyperglycemia. However, the specific combinations with other antidiabetic drugs and populations that will best benefit from these drugs are still being tested. Future research is also being conducted on the use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors in patients with type 1 diabetes.

Risk of bone fractures associated with glucagon-like peptide-1 receptor agonists' treatment: a meta-analysis of randomized controlled trials

Traditional anti-diabetic drugs may have negative or positive effects on risk of bone fractures. Yet the relationship between the new class glucagon-like peptide-1 receptor agonists (GLP-1 RA) and risk of bone fractures has not been established. We performed a meta-analysis including randomized controlled trials (RCT) to study the risk of bone fractures associated with liraglutide or exenatide, compared to placebo or other active drugs. We searched MEDLINE, EMBASE, and clinical trial registration websites for published or unpublished RCTs comparing the effects of liraglutide or exenatide with comparators. Only studies with disclosed bone fracture data were included. Separate pooled analysis was performed for liraglutide or exenatide, respectively, by calculating Mantel-Haenszel odds ratio (MH-OR). 16 RCTs were identified including a total of 11,206 patients. Liraglutide treatment was associated with a significant reduced risk of incident bone fractures (MH-OR=0.38, 95% CI 0.17-0.87); however, exenatide treatment was associated with an elevated risk of incident bone fractures (MH-OR=2.09, 95% CI 1.03-4.21). Publication bias and heterogeneity between studies were not observed. Our study demonstrated a divergent risk of bone fractures associated with different GLP-1 RA treatments. The current findings need to be confirmed by future well-designed prospective or RCT studies.

Long-term insulin glargine therapy in type 2 diabetes mellitus: a focus on cardiovascular outcomes

Cardiovascular disease is the leading cause of mortality in type 2 diabetes mellitus. Hyperinsulinemia is associated with increased cardiovascular risk, but the effects of exogenous insulin on cardiovascular disease progression have been less well studied. Insulin has been shown to have both cardioprotective and atherosclerosis-promoting effects in laboratory animal studies. Long-term clinical trials using insulin to attain improved diabetes control in younger type 1 and type 2 diabetes patients have shown improved cardiovascular outcomes. Shorter trials of intensive diabetes control with high insulin use in higher risk patients with type 2 diabetes have shown either no cardiovascular benefit or increased all cause and cardiovascular mortality. Glargine insulin is a basal insulin analog widely used to treat patients with type 1 and type 2 diabetes. This review focuses on the effects of glargine on cardiovascular outcomes. Glargine lowers triglycerides, leads to a modest weight gain, causes less hypoglycemia when compared with intermediate-acting insulin, and has a neutral effect on blood pressure. The Outcome Reduction With Initial Glargine Intervention (ORIGIN trial), a 6.2 year dedicated cardiovascular outcomes trial of glargine demonstrated no increased cardiovascular risk.

Twelve-month treatment with Liraglutide ameliorates Visceral Adiposity Index and common cardiovascular risk factors in type 2 diabetes outpatients

AIM

In addition to the effects on glycemic control and body weight, GLP-1 receptor agonists may favorably affect other major cardiovascular disease (CVD) risk factors, although currently available data are still sparse. In this retrospective study, we evaluated the effects of 12-month treatment with liraglutide on major CVD risk factors in 115 type 2 diabetes outpatients (60 men and 55 women), on stable hypoglycemic, anti-hypertensive and/or lipid-lowering therapy.

METHODS

Clinical and anthropometric data, metabolic and lipid profile, as well as the Visceral Adiposity Index (VAI), an obesity-related CVD risk factor, were measured in all participants at baseline and after 12-month treatment.

RESULTS

Treatment with liraglutide was associated with a significant reduction from baseline values of fasting blood glucose (-42.1 mg/dl, P < 0.05), HbA1c (-1.5 %, -17 mmol/mol, P < 0.05), body weight (-7.1 kg, P < 0.05), waist circumference (-6.8 cm, P < 0.001), total-cholesterol (-27.4 mg/dl, P < 0.05), LDL-cholesterol (-25.4 mg/dl, P < 0.05), triglycerides (-56.1 mg/dl, P < 0.05), and non-HDL-C (-36.6 mg/dl, P < 0.05) and an increase of HDL-cholesterol concentrations (+9.3 mg/dl, P < 0.001), a significant reduction in both systolic and diastolic blood pressure (-14.7 mmHg, P < 0.001 and -9.0 mmHg, P < 0.05, respectively) and a decrease of VAI values (-1.6, P < 0.001). All these differences were independent of changes in BMI and comparable in men and women.

CONCLUSIONS

In conclusion, 12-month treatment with liraglutide in add-on to on-going hypoglycemic therapy significantly ameliorates all major CVD risk factors and reduces cardiometabolic risk, as estimated by VAI values.

Effects of glucagon-like peptide-1 agents on left ventricular function: systematic review and meta-analysis

BACKGROUND

The cardiovascular safety of many glucagon-like peptide-1 agents (GLP-1 agents) is unclear. In this study, we assess the effects of the GLP-1 agents on left ventricular function in patients with type 2 diabetes (T2DM) and/or cardiovascular disease (CVD).

METHODS

PubMed, EMBASE, and the Cochrane Library were searched for the relevant publications up to May 2013 without restriction by language. All clinical controlled trials assessing left ventricular function and cardiovascular outcomes with the GLP-1 agents were selected for eligibility. Fourteen trials (415 patients) were identified as eligible between 1966 and 2013. Twelve of the studies were randomized controlled trials (RCT).

RESULTS

The results showed that GLP-1 agent treatment in patients with T2DM and/or CVD led to significantly improved regional left ventricular contractile parameters (including peak left systolic tissue velocity and strain) and global left ventricular performance (including stroke volume, ejection fraction, and left ventricular chambers) compared with patients receiving placebo.

CONCLUSIONS

GLP-1 agent treatment in T2DM and/or CVD patients is associated with a modest but significant increase in the odds of left ventricular contractile parameters and left ventricular performance compared with patients having received placebo, which may be indicative of additional cardiovascular benefits for these patients.

Defining the role of GLP-1 receptor agonists for individualized treatment of Type 2 diabetes

With the advent of dipeptidyl peptidase (DPP)-4 inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1 RAs) over the past decade, incretin therapy has become established as an important treatment strategy for Type 2 diabetes mellitus (T2DM), with an efficacy and safety profile distinct from that of other anti-hyperglycemic agents. However, our understanding of the optimal clinical use of incretins remains incomplete. This review focuses on the use of GLP-1 RAs in the treatment of T2DM, with reference to the differing dominant mechanisms of action between short- and long-acting GLP-1 RAs and the clinical implications of this difference. The role of GLP-1 and the effects of GLP-1 RAs in various organs other than the pancreas will also be discussed.

Liraglutide for the treatment of type 2 diabetes mellitus: a meta-analysis of randomized placebo-controlled trials

INTRODUCTION

Liraglutide has been widely used in the treatment of type 2 diabetes mellitus (T2DM), however, the results of a number of randomized placebo-controlled trials on the effects of liraglutide for the treatment of T2DM have varied. The purpose of this study was to assess the effects of liraglutide versus placebo for the treatment of T2DM.

METHODS

We searched randomized controlled trials comparing liraglutide and placebo for the treatment of T2DM in the following databases: MEDLINE; EMBASE; Cochrane Library Central Register of Controlled Trials; and Clinical Trials Gov (through August 2014). The standard mean difference (SMD) was calculated for the continuous data and a χ (2) test was used to evaluate heterogeneity.

RESULTS

Initially, 103 articles were retrieved through the literature search and 11 studies met the requirements for the meta-analysis. The effects of liraglutide on lowering glycosylated hemoglobin, fasting plasma glucose, reducing weight, lowering blood pressure, and the prevalence of adverse events were significantly different from placebo (P < 0.0001, SMD = -0.96, 95% CI = [-1.20, -0.73]; P < 0.0001, SMD = -0.72, 95% CI = [-0.99, -0.45]; P = 0.004, SMD = -0.24, 95% CI = [-0.40, -0.07]; P = 0.021, SMD = -0.15, 95% CI = [-0.27, -0.02], and P = 0.007, respectively).

CONCLUSION

Liraglutide had greater hypoglycemic, weight-reducing and systolic blood pressure-lowering effects than placebo. However, there were more adverse events in the treatment with liraglutide. It is suggested that additional well-designed, large, studies be conducted to further support the use of liraglutide and provide objective guidance for clinical application of liraglutide.

Contemporary treatment strategies for Type 2 diabetes-related macrovascular disease

Type 2 diabetes mellitus poses a major challenge to healthcare providers in the coming years as its prevalence increases across the globe. The disease doubles the risk of cardiovascular morbidity and mortality, with 70% of sufferers dying from a cardiac cause. Large clinical trials of current glucose-lowering therapies for Type 2 diabetes have shown no benefit in reducing the risk of macrovascular events. Blood pressure control, angiotensin-converting enzyme inhibitor therapy and improvement of dyslipidemia with statins have proven benefit in reducing cardiovascular risk in Type 2 diabetes. A growing understanding of the importance of pathological processes including endothelial dysfunction, abnormal growth factor biology, oxidative stress, dysregulation of adipokines and deficient vascular repair and regeneration in insulin-resistant states promises new treatments to combat the problem.

Gastrointestinal intervention ameliorates high blood pressure through antagonizing overdrive of the sympathetic nerve in hypertensive patients and rats

Background

We investigated the hypothesis that the favorable effects of gastrointestinal (GI) intervention on hypertension (HTN) and cardiovascular (CV) disturbances are mediated by antagonizing overdrive of the sympathetic nervous system (SNS).

Methods and Results

Hypertensive patients with metabolic disturbances underwent laparoscopic Roux‐en‐Y gastric bypass surgery, and spontaneously hypertensive rats (SHRs) underwent RYGB or sham surgery. Blood pressure (BP), heart rate (HR), endothelium‐dependent flow‐mediated dilation, and anthropometric as well as laboratory parameters were measured at baseline and during follow‐up. Changes of BP and HR in response to cold stress, renal sympathetic nervous activity (RSNA), vasoconstriction induced by electrical field stimulation, microinjection of nucleus of the solitary tract (NTS), and CV function and structure were examined in SHRs with or without surgery. Compared with baseline, BP and HR were significantly reduced in both hypertensive patients with type 2 diabetes and rats. Impaired endothelial‐dependent vasodilatation and metabolic disturbances in hypertensive patients were also ameliorated after surgery. CV disturbances were reversed by surgery in SHRs. Under acute cold exposure, the variations in BP and HR were smaller in surgically treated SHRs, compared to sham SHRs. RSNA and vasoconstriction induced by perivascular nerve stimulation as well as NTS‐mediated changes of BP were decreased in surgically treated SHRs, compared to sham SHR. Weight loss did not affect BP and RSNA in sham SHRs.

Conclusions

GI intervention ameliorates HTN in both hypertensive patients and rats by inhibiting overdrive of the SNS. Therefore, targeting gastrointestine could be a novel strategy to treat HTN with metabolic disturbances.

Effects of GLP-1 in the kidney

The incretin hormone, glucagon-like peptide-1 (GLP-1), stimulates insulin secretion and forms the basis of a new drug class for diabetes treatment. GLP-1 has several extra-pancreatic properties which include effects on kidney function. Although renal GLP-1 receptors have been identified, their exact localization and physiological role are incompletely understood. GLP-1 increases natriuresis through inhibition of the sodium-hydrogen ion exchanger isoform 3 in the proximal tubule. This may in part explain why GLP-1 receptor agonists have antihypertensive effects. Glomerular filtration rate is regulated by GLP-1, but the mechanisms are complex and may depend on e.g. glycaemic conditions. Atrial natriuretic peptide or the renin-angiotensin system may be involved in the signalling of GLP-1-mediated renal actions. Several studies in rodents have shown that GLP-1 therapy is renoprotective beyond metabolic improvements in models of diabetic nephropathy and acute kidney injury. Inhibition of renal inflammation and oxidative stress probably mediate this protection. Clinical studies supporting GLP-1-mediated renal protection exist, but they are few and with limitations. However, acute and chronic kidney diseases are major global health concerns and measures improving renal outcome are highly needed. Therefore, the renoprotective potential of GLP-1 therapy need to be thoroughly investigated in humans.

The pathophysiology of hypertension in patients with obesity

The combination of obesity and hypertension is associated with high morbidity and mortality because it leads to cardiovascular and kidney disease. Potential mechanisms linking obesity to hypertension include dietary factors, metabolic, endothelial and vascular dysfunction, neuroendocrine imbalances, sodium retention, glomerular hyperfiltration, proteinuria, and maladaptive immune and inflammatory responses. Visceral adipose tissue also becomes resistant to insulin and leptin and is the site of altered secretion of molecules and hormones such as adiponectin, leptin, resistin, TNF and IL-6, which exacerbate obesity-associated cardiovascular disease. Accumulating evidence also suggests that the gut microbiome is important for modulating these mechanisms. Uric acid and altered incretin or dipeptidyl peptidase 4 activity further contribute to the development of hypertension in obesity. The pathophysiology of obesity-related hypertension is especially relevant to premenopausal women with obesity and type 2 diabetes mellitus who are at high risk of developing arterial stiffness and endothelial dysfunction. In this Review we discuss the relationship between obesity and hypertension with special emphasis on potential mechanisms and therapeutic targeting that might be used in a clinical setting.

Cardiovascular effects of incretin therapy in diabetes care

Diabetes patients are at high risk for development of cardiovascular disease. The cardiovascular safety of antidiabetic medications is a concern. Incretin therapies, including glucagon-like peptide 1 receptor (GLP-1) receptor agonists and dipeptidyl peptidase 4 (DPP-4) inhibitors, have recently been introduced to clinical practice and are widely used. Data from phase 2 and 3 trials and retrospective analyses of clinical databases have shown favorable changes in cardiovascular risk factors and outcomes. However, only a few prospective trials have been designed with cardiovascular outcomes as a primary end point. From current data, alogliptin and saxagliptin do not change cardiovascular risk in type 2 diabetes mellitus (T2DM) patients. Vildagliptin does not alter myocardial function in T2DM patients with systolic dysfunction. However, the possibility of an increase in clinical heart failure and worsened outcomes in patients with existing heart failure is suggested by current data. Clinicians need to follow patients on DPP-4 inhibitors carefully for this possibility until more prospective randomized controlled data are available.

Reductions in systolic blood pressure with liraglutide in patients with type 2 diabetes: insights from a patient-level pooled analysis of six randomized clinical trials

AIMS

To quantify the effect of liraglutide on systolic blood pressure (SBP) and pulse in patients with type 2 diabetes (T2D), and assess the influence of covariates on observed SBP reductions.

METHODS

A patient-level pooled analysis of six phase 3, randomized trials was conducted.

RESULTS

The analysis included 2792 randomized patients. In the intention-to-treat population (n=2783), mean [±SE] SBP reductions from baseline with liraglutide 1.2 mg (2.7 [0.8] mmHg) and 1.8 mg (2.9 [0.7] mmHg) once daily were significantly greater than with placebo (0.5 [0.9] mmHg; P=0.0029 and P=0.0004, respectively) after 26 weeks, and were evident after 2 weeks. Liraglutide was also associated with significantly greater SBP reductions than glimepiride and, at a dose of 1.8 mg, insulin glargine and rosiglitazone. SBP reductions with liraglutide weakly correlated with weight loss (Pearson's correlation coefficient: 0.08-0.12; P≤0.0148). No dependence of these reductions on concomitant antihypertensive medications was detected (P=0.1304). Liraglutide 1.2 and 1.8 mg were associated with mean increases in pulse of 3 beats per minute (bpm), versus a 1 bpm increase with placebo (P<0.0001 for each dose versus placebo).

CONCLUSIONS

Liraglutide reduces SBP in patients with T2D, including those receiving concomitant antihypertensive medication.

Complementary Approaches to Improving Glucose Control-Insulin and Incretins: Patient Case Studies in Action

PURPOSE

The use of insulin and incretin-based therapies together has recently emerged as a new therapeutic option for patients with type 2 diabetes. This approach can be used across the continuum of diabetes and is supported by clinical trial evidence. To illustrate how these data may apply to clinical care, this supplement uses patient case studies to provide clinical context for diabetes educators. Relevant medical literature was searched and cited. Search terms included insulin, DPP-4 inhibitors, GLP-1 receptor agonists, hypoglycemia, and weight gain.

CONCLUSION

Insulin remains the most potent glucose-lowering agent available for the treatment of type 2 diabetes but has limitations, primarily of hypoglycemia and secondarily of weight gain. The addition of incretin-based therapies complements the glucose-lowering potential of basal insulin, without increasing the risk of hypoglycemia, potentially allowing for lower doses of insulin and without increasing weight gain (DPP-4 inhibitors) or possibly with weight loss (GLP-1 receptor agonists). Incretin-based therapies offer advantages over prandial insulin to address postprandial hyperglycemia.