Postprandial renal haemodynamic effect of lixisenatide vs once-daily insulin-glulisine in patients with type 2 diabetes on insulin-glargine: An 8-week, randomised, open-label trial

The influence of insulin and incretin-based therapies on renal tubular transport

The tubular function of the kidney is very complex and is finely regulated by many factors. These include a variety of hormonal signaling pathways which are involved in the expression, activation and regulation of renal transporters responsible for the handling of electrolytes. Glucose-lowering drugs such as insulin and incretin-based therapies, exert a well-known renal protective role in diabetic kidney disease, mainly acting at the glomerular level. In the literature, several studies have described the effect of insulin and the incretin hormones on tubular transport. Most of these studies focused on the variations in excretion and clearance of sodium but did not extensively and systematically investigate the possible variations that these hormones may induce in the tubular regulation of all the other electrolytes, urea metabolism, acid-base balance and urinary pH. While insulin action on the kidney is very well-described, the renal tubular impact of incretin-based therapies is less consistent and the results available are scarce. To our knowledge, this is the first review summarizing the effects induced on renal tubules by insulin, glucagon-like peptide-1 (GLP-1) receptor agonists and serine protease dipeptidyl peptidase-4 (DPP4) inhibitors in both healthy and diabetic human subjects. This is significant because it highlights the existence of a renal-gut and pancreas axis which also has a direct tubular effect and enables a deeper understanding of renal physiology.

Incretin and glucagon receptor polypharmacology in chronic kidney disease

Chronic kidney disease is a debilitating condition associated with significant morbidity and mortality. In recent years, the kidney effects of incretin-based therapies, particularly glucagon-like peptide-1 receptor agonists (GLP-1RAs), have garnered substantial interest in the management of type 2 diabetes and obesity. This review delves into the intricate interactions between the kidney, GLP-1RAs, and glucagon, shedding light on their mechanisms of action and potential kidney benefits. Both GLP-1 and glucagon, known for their opposing roles in regulating glucose homeostasis, improve systemic risk factors affecting the kidney, including adiposity, inflammation, oxidative stress, and endothelial function. Additionally, these hormones and their pharmaceutical mimetics may have a direct impact on the kidney. Clinical studies have provided evidence that incretins, including those incorporating glucagon receptor agonism, are likely to exhibit improved kidney outcomes. Although further research is necessary, receptor polypharmacology holds promise for preserving kidney function through eliciting vasodilatory effects, influencing volume and electrolyte handling, and improving systemic risk factors.

The effect of subcutaneous Lixisenatide on weight loss in patients with type 2 Diabetes Mellitus: Systematic review and Meta-Analysis of randomized controlled trials

BACKGROUND

The impacts of subcutaneous Lixisenatide on body weight in patients with type 2 DM, remain inadequately understood; consequently, this systematic review and meta-regression analysis of randomized controlled trials (RCTs) was conducted to evaluate the influence of subcutaneous Lixisenatide administration on BW and BMI values in individuals with Type 2 diabetes.

METHODS

A comprehensive literature search was conducted across four databases, spanning from their inception to February 2023. We computed effect sizes employing the random-effects model and reported results in terms of weighted mean differences (WMD) along with their corresponding 95% confidence intervals (CI).

RESULTS

23 articles with 26 RCT arms were included in the meta-analysis. The combined findings from a random-effects model demonstrated a significant reduction in body weight (WMD: -0.97 kg, 95 % CI: -1.10, -0.83, p < 0.001) and BMI (WMD: -0.48 kg/m2, 95 % CI: -0.67, -0.29, P < 0.001) after subcutaneous administration of Lixisenatide. Furthermore, a more pronounced reduction in body weight was discovered in RCTs lasting less than 24 weeks (WMD: -1.56 kg, 95 % CI: -2.91, -0.20, p < 0.001), employing a daily dosage of subcutaneous Lixisenatide lower than 19 Âµg per day (WMD: -1.94 kg, 95 % CI: -2.54, -1.34, p < 0.001) and with a mean participant age of 60 years or more (WMD: -1.86 kg, 95 % CI: -3.16, -0.57, p = 0.005).

CONCLUSIONS

Lixisenatide was found to significantly decrease BW and BMI in patients with type 2 DM and could be considered as a therapeutic option for those suffering from weight gain caused by other anti-diabetic agents. However, while prescribing Lixisenatide, careful consideration of patient-specific factors is recommended.

The effects of semaglutide, empagliflozin and their combination on the kidney sodium signal from magnetic resonance imaging: A prespecified, secondary analysis from a randomized, clinical trial

AIMS

To evaluate the effect of treatment with semaglutide and empagliflozin on the cortico-medullary sodium gradient (MCR; medulla/cortex ratio), urine sodium/creatinine ratio (UNACR), and estimated plasma volume (ePV) and to compare the MCR between persons with and without type 2 diabetes.

METHODS

Using the 23Na magnetic resonance imaging (23Na-MRI) technique, we investigated the effects of 32 weeks of treatment with semaglutide, empagliflozin or their combination on MCR in 65 participants with type 2 diabetes and high risk of cardiovascular disease. The participants were recruited from a randomized, controlled interventional trial and further characterized by UNACR and ePV. In addition, in a cross-sectional design, we compared MCR by 23Na-MRI in 12 persons with type 2 diabetes and 17 matched controls. Data from the interventional trial were analyzed using a single, multivariate linear mixed model strategy for repeated measurements. Data from the cross-sectional study were analyzed by fitting a linear regression model adjusted for age and sex.

RESULTS

Compared to placebo, semaglutide, but not empagliflozin, significantly decreased the MCR (-9 %, 95%CI (-18, -0.06)%, p = 0.035 and -0.05 %, 95%CI(-0.15, 0.05)%, p = 0.319, respectively). The UNACR decreased in the semaglutide group(-35 %, 95 % CI(-52, -14) %, p = 0.003) but not in the empagliflozin group (7 %, 95 % CI(-21, 44)%, p = 0.657), whereas the ePV decreased in the combination group. The MCR was not different between persons with and without type 2 diabetes.

CONCLUSION

23Na magnetic resonance imaging can identify drug induced changes in the MCR in persons with type 2 diabetes, and 32 weeks of semaglutide decreases the MCR in such persons. There is no difference in the MCR between persons with and without type 2 diabetes.

TRIAL NUMBER AND REGISTRY

EUDRACT 2019-000781-38, clinicaltrialsregister.eu.

Glucagon-like peptide 1(GLP-1) receptor agonists in the management of the patient with type 2diabetes mellitus and chronic kidney disease: an approach for the nephrologist

Diabetic kidney disease, a common complication in patients with type 2 diabetes mellitus, is associated with a markedly increased morbidity and mortality, especially of cardiovascular origin, and faster progression to end-stage renal disease. To date, reducing cardiovascular and renal risk in this population was based on strict control of cardiovascular risk factors and the renin-angiotensin system blockade. More recently, sodium-glucose cotransporter type 2 inhibitors have demonstrated to offer cardiovascular and renal protection, but the residual risk remains high and their antihyperglycemic efficacy is limited in moderate-severe CKD. Therefore, drugs with a potent antihyperglycemic effect, independent of the glomerular filtration rate, with a low risk of hypoglycemia, that reduce weight in overweight/obese patients and that provide cardiovascular and renal protection, such as GLP-1 receptor agonists, are needed. However, these drugs require subcutaneous administration, which may limit their early use. The recent availability of oral semaglutide may facilitate the early introduction of this family with proven cardiovascular and renal benefits and excellent safety profile. In this review the family is analyzed as well as their cardiovascular and renal effects.

Exposure-Response Analysis of the Sodium-Glucose Cotransporter-2 Inhibitors Dapagliflozin and Empagliflozin on Kidney Hemodynamics in Patients with Type 2 Diabetes

Sodium-glucose cotransporter-2 (SGLT2) inhibitors improve markers for renal and cardiovascular outcomes in patients with and without type 2 diabetes (T2D). To assess whether individual differences in plasma drug exposure can explain inter-individual response variation, we characterized the exposure-response relationship for two SGLT2 inhibitors on several clinical and kidney hemodynamic variables. Data were obtained from two studies, RED and RECOLAR, assessing the effects of once-daily 10 mg dapagliflozin or empagliflozin, respectively, on kidney hemodynamics in patients with T2D. Individual plasma exposure was estimated using non-compartmental analyses and exposure-response relationships were assessed using linear mixed-effects models. In 23 patients participating in RED, the dapagliflozin geometric mean apparent area under the concentration-time curve during one dosing interval at steady state (AUC_0-tau,ss) was 1153.1 µg/L*h (coefficient of variation (CV) 81.8%) and associated, per doubling, with decreases in body weight (0.29 kg, p < 0.001), systolic blood pressure (0.80 mmHg, p = 0.002), measured glomerular filtration rate (mGFR) (0.83 mL/min, p = 0.03), and filtration fraction (0.09%, p = 0.04). In 20 patients participating in RECOLOR, the empagliflozin geometric mean AUC_0-tau,ss was 2035.7 nmol/L*h (CV 48.4%) and associated, per doubling, with decreases in body weight (0.13 kg, p = 0.002), systolic blood pressure (0.65 mmHg, p = 0.045), and mGFR (0.78 mL/min, p = 0.002). To conclude, dapagliflozin and empagliflozin plasma exposure was highly variable between patients and associated with inter-individual variation in response variables.

The postprandial actions of GLP-1 receptor agonists: The missing link for cardiovascular and kidney protection in type 2 diabetes

Recent clinical trials in people with type 2 diabetes have demonstrated beneficial actions on heart and kidney outcomes following treatment with GLP-1RAs. In part, these actions are consistent with improved glucose control and significant weight loss. But GLP-1RAs may also have additive benefits by improving postprandial dysmetabolism. In diabetes, dysregulated postprandial nutrient excursions trigger inflammation, oxidative stress, endothelial dysfunction, thrombogenicity, and endotoxemia; alter hormone levels; and modulate cardiac output and regional blood and lymphatic flow. In this perspective, we explore the actions of GLP-1RAs on the postprandial state and their potential role in end-organ benefits observed in recent trials.

Nephroprotective Properties of the Glucose-Dependent Insulinotropic Polypeptide (GIP) and Glucagon-like Peptide-1 (GLP-1) Receptor Agonists

Diabetes mellitus is the leading cause of chronic kidney disease, and about 30–40% of patients with diabetes will develop kidney disease. Incretin hormones have received attention during the past three decades not only as a pharmacotherapy for the treatment of type 2 diabetes, but also for their cardiorenometabolic effects. The main incretins are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Additional to the pancreas, receptors for GLP-1 are widely distributed in various organs, causing positive effects on endothelial function and vascular atherogenesis. Along with glycemic control and weight reduction, GLP-1 receptor agonists also strongly improve cardiovascular and renal outcomes in patients with type 2 diabetes. Recently, a dual GIP and GLP-1 receptor agonist has been approved for the treatment of type 2 diabetes. Compared to GLP-1 receptor agonist semaglutide, dual GIP and GLP-1 receptor agonist tirzepatide showed a superior reduction in hemoglobin A1c and body weight. Preliminary results also suggest that tirzepatide improves kidney outcomes in adults with type 2 diabetes with increased cardiovascular risk. In this review, we present the nephroprotective properties of dual GIP and GLP-1 receptor agonists as a new drug to treat type 2 diabetes.

Effect of glucagon-like peptide 1 receptor agonists on albuminuria in adult patients with type 2 diabetes mellitus: A systematic review and meta-analysis

AIMS

To determine the effect of glucagon-like peptide 1 receptor agonists (GLP-1RAs) on albuminuria in adult patients with type 2 diabetes mellitus (T2DM).

METHODS

Medline Ovid, Scopus, Web of Science, EMCARE and CINAHL databases from database inception until 27 January 2022. Studies were eligible for inclusion if they were randomized controlled trials that involved treatment with a GLP-1RA in adult patients with T2DM and assessed the effect on albuminuria in each treatment arm. Data extraction was conducted independently by three individual reviewers. The PRISMA guidelines were followed regarding data extraction and quality assessment. Data were pooled using a random effects inverse variance model and all analysis was carried out with RevMan 5.4 software. The Jadad scoring tool was employed to assess the quality of evidence and risk of bias in the randomized controlled trials.

RESULTS

The initial search revealed 2419 articles, of which 19 were included in this study. An additional three articles were identified from hand-searching references of included reviews. Therefore, in total, 22 articles comprising 39 714 patients were included. Meta-analysis suggested that use of GLP1-RAs was associated with a reduction in albuminuria in patients with T2DM (weighted mean difference -16.14%, 95% CI -18.42 to -13.86%; p < .0001) compared with controls.

CONCLUSIONS

This meta-analysis indicates that GLP-1RAs are associated with a significant reduction in albuminuria in adult patients with T2DM when compared with placebo.

Cardiovascular effects of incretins - focus on GLP-1 receptor agonists

GLP-1 receptor agonists (GLP-1 RAs) have been used to treat patients with type 2 diabetes since 2005 and have become popular because of the efficacy and durability in relation to glycaemic control in combination with weight loss in most patients. Today in 2022, seven GLP-1 RAs, including oral semaglutide are available for treatment of type 2 diabetes. Since the efficacy in relation to reduction of HbA1c and body weight as well as tolerability and dosing frequency vary between agents, the GLP-1 RAs cannot be considered equal. The short acting lixisenatide showed no cardiovascular benefits, while once daily liraglutide and the weekly agonists, subcutaneous semaglutide, dulaglutide, and efpeglenatide, all lowered the incidence of cardiovascular events. Liraglutide, oral semaglutide and exenatide once weekly also reduced mortality. GLP-1 RAs reduce the progression of diabetic kidney disease. In the 2019 consensus report from EASD/ADA, GLP-1 RAs with demonstrated cardio-renal benefits (liraglutide, semaglutide and dulaglutide) are recommended after metformin to patients with established cardiovascular diseases or multiple cardiovascular risk factors. European Society of Cardiology (ESC) suggests starting with a SGLT-2 inhibitor or a GLP-1 RA in drug naïve patients with type 2 diabetes and atherosclerotic CVD or high CV Risk. However, the results from cardiovascular outcome trials (CVOT) are very heterogeneous suggesting that some GLP-1RA are more suitable to prevent CVD than others. The CVOTs provide a basis upon which individual treatment decisions for patients with T2D and CVD can be made.

Comparing the effects of twice-daily exenatide and insulin on renal function in patients with type 2 diabetes mellitus: secondary analysis of a randomized controlled trial

This is a secondary analysis of a randomized controlled trial (RCT) on the effects of the glucagon-like peptide-1 receptor agonists exenatide and insulin aspartate 30 injection on carotid intima-media thickness. Here, we report the renal outcomes of the intervention in patients with type 2 diabetes mellitus (T2DM). Data from the RCT study was used to evaluate the effect of exenatide or insulin given for 52 weeks on estimated glomerular filtration rate (eGFR) in patients with T2DM. The primary end point was the change in the eGFR from baseline between the exenatide and insulin groups in normal versus overweight patients and patients with obesity. The secondary end point was the correlation between change in eGFR and oxidative stress, glycemic control, and dyslipidemia. There was a significant difference in eGFR between the insulin and exenatide groups at 52 weeks (p=0.0135). Within the insulin group, the eGFR remained below baseline at 52 weeks in all patients, and there was an increase in body weight in the normal group compared with the overweight patients and patients with obesity. The opposite was observed in the exenatide group. A decrease in body weight was prominent in the exenatide group at 52 weeks (p<0.05), the eGFR was below baseline in overweight patients and patients with obesity and significantly above baseline in the normal group (p<0.05). The eGFR was positively correlated to 8-oxo-7,8-dihydroguanosine in the insulin group (p<0.05) but not the exenatide group. It can be concluded that compared with insulin, exenatide may improve renal function in overweight patients and patients with obesity more than in normal-weight patients with T2DM, but a further RCT is needed to confirm this effect.

Glomerular filtration rate as a kidney outcome of diabetic kidney disease: a focus on new antidiabetic drugs

Diabetes has reached epidemic proportions, both in Korea and worldwide and is associated with an increased risk of chronic kidney disease and kidney failure (KF). The natural course of kidney function among people with diabetes (especially type 2 diabetes) may be complex in real-world situations. Strong evidence from observational data and clinical trials has demonstrated a consistent association between decreased estimated glomerular filtration rate (eGFR) and subsequent development of hard renal endpoints (such as KF or renal death). The disadvantage of hard renal endpoints is that they require a long follow-up duration. In addition, there are many patients with diabetes whose renal function declines without the appearance of albuminuria, measurement of the eGFR is emphasized. Many studies have used GFR-related parameters, such as its change, decline, or slope, as clinical endpoints for kidney disease progression. In this respect, understanding the trends in GFR changes could be crucial for developing clinical management strategies for the prevention of diabetic complications. This review focuses on the clinical implication of the eGFR-related parameters that have been used so far in diabetic kidney disease. We also discuss the use of recently developed new antidiabetic drugs for kidney protection, with a focus on the GFR as clinical endpoints.

Research Progress on the Cardiovascular Protective Effect of Glucagon-Like Peptide-1 Receptor Agonists

The risk of cardiovascular diseases is closely related to diabetes. Macrovascular disease is the main cause of death and disability in patients with type 2 diabetes. In recent years, the glucagon-like peptide-1 receptor agonist (GLP-1RA), a new type of hypoglycemic drug, has been shown to regulate blood sugar levels, improve myocardial ischemia, regulate lipid metabolism, improve endothelial function, and exert a protective role in the cardiovascular system. This study reviewed the protective effects of GLP-1RA on the cardiovascular system.

The effect of Glucagon-like peptide-1 receptor agonists on serum uric acid concentration: A systematic review and meta-analysis

AIMS

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a class of medications mainly used for the treatment of type 2 diabetes. They improve glucose tolerance, increase insulin secretion, and induce weight loss. There is controversy about the effect of GLP-1RAs on serum uric acid (SUA) concentration. Our systematic review aims to objectively answer whether GLP-1RAs affect SUA levels.

METHODS

We performed a systematic search on PubMed, Web of Science, Embase, Scopus, and Google Scholar datasets up to 27August,2021 with a language restriction of English only. Randomized controlled trials, observational studies, uncontrolled trials, and conference abstracts were included. Studies with insufficient data, irrelevant types of study, and follow-up duration of less than a month were excluded from the review. After critical appraisal by the Joanna Briggs Institute checklists, articles underwent data extraction using a pre-specified Microsoft Excel sheet.

RESULTS

Of 1004 identified studies, 17 were eligible for inclusion in this systematic review. Pre- to post-administration analysis of GLP-1RA effects on SUA demonstrated that GLP-1RAs could significantly reduce SUA concentration (difference in means=-0.341;SE=0.063;P-value<0.001). However, when compared to placebo, GLP-1 RAs did not perform any better in lowering SUA concentration (difference in means=-0.455;SE=0.259;P-value=0.079). Surprisingly, the active controls, that included insulin, metformin, sodium-glucose co-transporter 2 (SGLT-2) inhibitors, and dipeptidyl-peptidase 4 (DPP-4) inhibitors, did outperform GLP-1RAs in reducing SUA concentration (difference in means=0.250;SE=0.038;P-value<0.001).

CONCLUSIONS

Administration of GLP-1RAs can result in a significant reduction in SUA concentration. However, this reduction is less than that seen with the use of insulin, metformin, and SGLT-2 inhibitors.

Postprandial renal haemodynamic effects of the dipeptidyl peptidase-4 inhibitor linagliptin versus the sulphonylurea glimepiride in adults with type 2 diabetes (RENALIS): A predefined substudy of a randomized, double-blind trial

AIM

To determine the effect of the dipeptidyl peptidase-4 inhibitor linagliptin on postprandial glomerular hyperfiltration compared with the sulphonylurea glimepiride in adults with type 2 diabetes (T2D).

MATERIALS AND METHODS

In this predefined substudy within a randomized, double-blind, parallel-group, intervention trial, overweight people with T2D without renal impairment were treated with once-daily linagliptin 5 mg (N = 10) or glimepiride 1 mg (N = 13) as an add-on to metformin for 8 weeks. After a standardized liquid protein-rich meal, the glomerular filtration rate (GFR) and effective renal plasma flow were determined by inulin and para-aminohippuric acid clearance, respectively, based on timed urine sampling. Intrarenal haemodynamics were estimated using the Gomez equations. Glucoregulatory/vasoactive hormones, urinary pH and fractional excretions (FE) of sodium, potassium and urea were measured.

RESULTS

Compared with glimepiride, linagliptin increased the postprandial filtration fraction (FF; mean difference 2.1%-point; P = .016) and estimated glomerular hydraulic pressure (mean difference 3.0 mmHg; P = .050), and tended to increase GFR (P = .08) and estimated efferent renal arteriolar resistance (R_E ; P = .08) from baseline to week 8. No differences in FE were noted. Glimepiride reduced HbA1c more than linagliptin (mean difference -0.40%; P = .004), without between-group differences in time-averaged postprandial glucose levels. In the linagliptin group, change in FF correlated with change in mean arterial pressure (R = 0.807; P = .009) and time-averaged mean glucagon (R = 0.782; P = .008), but not with changes in glucose, insulin, intact glucagon-like peptide-1, renin or FE_Na . Change in glucagon was associated with change in R_E (R = 0.830; P = .003).

CONCLUSIONS

In contrast to our hypothesis, compared with glimepiride, linagliptin does not reduce postprandial hyperfiltration, yet appears to increase FF after meal ingestion by increasing blood pressure or R_E .

Incretins in the Therapy of Diabetic Kidney Disease

Diabetic kidney disease is a microvascular complication that occurs in patients with diabetes. It is strongly associated with increased risk of kidney replacement therapy and all-cause mortality. Incretins are peptide hormones derived from the gastrointestinal tract, that besides causing enhancement of insulin secretion after oral glucose intake, participate in many other metabolic processes. Antidiabetic drug classes, such as dipeptidyl peptidase 4 inhibitors and glucagon-like peptide receptor agonists, which way of action is based on incretins facility, not only show glucose-lowering properties but also have nephroprotective functions. The aim of this article is to present the latest information about incretin-based therapy and its influence on diabetic kidney disease appearance and progression, point its potential mechanisms of kidney protection and focus on future therapeutic possibilities bound with these two antidiabetic drug classes.

Obesity-Related Glomerulopathy: Clinical Management

Obesity-related glomerulopathy (ORG) and other obesity-associated kidney diseases pose a major challenge to the treating nephrologist. We review the benefits of weight loss and optimal management of ORG and kidney disease in the setting of obesity. Therapeutic strategies in ORG were limited mainly in the past to weight loss through lifestyle interventions and bariatric surgery, antihypertensive treatment, and renin-angiotensin-aldosterone system blockade. Current approaches to obtain the desired weight loss include novel pharmacologic therapies that have been approved for the treatment of diabetes while offering kidney protection, such as sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1-receptor agonists. This review focuses on the nephroprotective role of the renin-angiotensin-aldosterone system blockade and of these new pharmacologic agents, and on the renal effects of bariatric surgery in chronic kidney disease.

Glucagon-Like Peptide-1 Receptor Agonists-Use in Clinical Practice

In the past 2 decades, eight glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been approved for the management of type 2 diabetes, each with its peculiar molecular structure, pharmacokinetics, and metabolic effects. Along with their marked glucose-lowering actions, which occur both at fasting and in the postprandial phase without an increased risk of hypoglycemia, GLP-1RAs have provided marked reductions in body weight and ancillary improvements in blood pressure and lipid profile. Recent cardiovascular outcome trials have established the benefits of GLP-1RAs on major cardiovascular events and all-cause mortality, independent of glucose control, with minor effects on preventing hospitalization for heart failure. Novel evidence is also emerging on the protection of GLP-1RAs against diabetic kidney disease, mainly preventing the onset of macroalbuminuria. Several mechanisms have been proposed to explain the cardiorenal protective properties of GLP-1RAs, which may be direct or mediated by additional hemodynamic and anti-inflammatory/antioxidant effects. With their favorable cardiometabolic properties and safety profile, GLP-1RAs may offer an ideal pharmacological option for the management of diabetic kidney disease. In this review, we discuss pharmacokinetic properties, glucometabolic effects, and cardioprotective actions of GLP-1RAs, highlighting the available evidence for a kidney protective role and the proposed mechanisms.

Incretin drugs in diabetic kidney disease: biological mechanisms and clinical evidence

As the prevalence of diabetes continues to climb, the number of individuals living with diabetic complications will reach an unprecedented magnitude. The emergence of new glucose-lowering agents - sodium-glucose cotransporter 2 inhibitors and incretin therapies - has markedly changed the treatment landscape of type 2 diabetes mellitus. In addition to effectively lowering glucose, incretin drugs, which include glucagon-like peptide 1 receptor (GLP1R) agonists and dipeptidyl peptidase 4 (DPP4) inhibitors, can also reduce blood pressure, body weight, the risk of developing or worsening chronic kidney disease and/or atherosclerotic cardiovascular events, and the risk of death. Although kidney disease events have thus far been secondary outcomes in clinical trials, an ongoing phase III trial in patients with diabetic kidney disease will test the effect of a GLP1R agonist on a primary kidney disease outcome. Experimental data have identified the modulation of innate immunity and inflammation as plausible biological mechanisms underpinning the kidney-protective effects of incretin-based agents. These drugs block the mechanisms involved in the pathogenesis of kidney damage, including the activation of resident mononuclear phagocytes, tissue infiltration by non-resident inflammatory cells, and the production of pro-inflammatory cytokines and adhesion molecules. GLP1R agonists and DPP4 inhibitors might also attenuate oxidative stress, fibrosis and cellular apoptosis in the kidney.

Renoprotection in diabetic kidney disease: can incretin-based therapies deliver?

PURPOSE OF REVIEW

Incretin-based therapies mimic or augment the gut-hormone glucagon-like peptide (GLP)-1 and, due to their glucose-lowering potential and beneficial safety profile, as well as their cardiovascular safety and/or protection, are prescribed on a large scale to treat individuals with type 2 diabetes (T2D). However, whether the two drug-classes that belong to this category, respectively GLP-1 receptor agonists and dipeptidyl peptidase (DPP)-4 inhibitors, also reduce the risk of diabetic kidney disease (DKD) is at present heavily debated. This review aims to discuss the current evidence.

RECENT FINDINGS

Evidence from land-mark cardiovascular safety trials, conducted in people with T2D at high-cardiovascular risk but with normal kidney function, suggest that both drug-classes have excellent renal safety profiles. In contrast to DPP-4 inhibitors, it seems that GLP-1 receptor agonists reduce albuminuria and possibly induce a reduction of estimated glomerular filtration rate decline. However, the trials were not properly designed to test renal outcomes.

SUMMARY

A dedicated renal trial involving a GLP-1 receptor agonist has recently commenced and will answer the question whether these drugs will be effective to reduce DKD. Moreover, ongoing mechanism-of-action studies are focusing on the renal physiological effects of GLP-1, as the effects on particularly albuminuria reduction remain currently unexplained.

Diabetes and Its Complications: Therapies Available, Anticipated and Aspired

Worldwide, diabetes ranks among the ten leading causes of mortality. Prevalence of diabetes is growing rapidly in low and middle income countries. It is a progressive disease leading to serious co-morbidities, which results in increased cost of treatment and over-all health system of the country. Pathophysiological alterations in Type 2 Diabetes (T2D) progressed from a simple disturbance in the functioning of the pancreas to triumvirate to ominous octet to egregious eleven to dirty dozen model. Due to complex interplay of multiple hormones in T2D, there may be multifaceted approach in its management. The 'long-term secondary complications' in uncontrolled diabetes may affect almost every organ of the body, and finally may lead to multi-organ dysfunction. Available therapies are inconsistent in maintaining long term glycemic control and their long term use may be associated with adverse effects. There is need for newer drugs, not only for glycemic control but also for prevention or mitigation of secondary microvascular and macrovascular complications. Increased knowledge of the pathophysiology of diabetes has contributed to the development of novel treatments. Several new agents like Glucagon Like Peptide - 1 (GLP-1) agonists, Dipeptidyl Peptidase IV (DPP-4) inhibitors, amylin analogues, Sodium-Glucose transport -2 (SGLT- 2) inhibitors and dual Peroxisome Proliferator-Activated Receptor (PPAR) agonists are available or will be available soon, thus extending the range of therapy for T2D, thereby preventing its long term complications. The article discusses the pathophysiology of diabetes along with its comorbidities, with a focus on existing and novel upcoming antidiabetic drugs which are under investigation. It also dives deep to deliberate upon the novel therapies that are in various stages of development. Adding new options with new mechanisms of action to the treatment armamentarium of diabetes may eventually help improve outcomes and reduce its economic burden.

Nephroprotective effects of GLP-1 receptor agonists: where do we stand?

Glucagon-like peptide (GLP)-1 receptor agonists are the cornerstone in the treatment of hyperglycemia in many people suffering from type 2 diabetes (T2D). These drugs have potent glucose-lowering actions and, additionally, lower body weight through satiety induction while reducing blood pressure and dyslipidemia. Partly through these actions, GLP-1 receptor agonism was shown to reduce cardiovascular disease (CVD) in people with T2D with previous CVD or at high-risk thereof. In these cardiovascular safety trials, in secondary or exploratory analyses, GLP-1 receptor agonists were also shown to reduce macro-albuminuria, an accepted surrogate marker for diabetic kidney disease (DKD), a condition that still represents a major unmet medical need. In this review we will discuss the evidence which suggests renoprotection induced by GLP-1 receptor agonists and the potential mechanisms that may be involved. These include mitigation of hyperglycemia, overweight and insulin resistance, systemic and glomerular hypertension, dyslipidemia, sodium retention, inflammation and renal hypoxia. The recently initiated large-sized FLOW trial investigating the effects of semaglutide on hard renal outcomes in patients with DKD will provide clarity whether GLP-1 receptor agonists may reduce the burden of DKD in addition to their other beneficial metabolic and cardiovascular effects.

Glucagon-like peptide-1 receptors in the kidney: impact on renal autoregulation

Glucagon-like peptide-1 (GLP-1) and strategies based on this blood sugar-reducing and appetite-suppressing hormone are used to treat obesity and type 2 diabetes. However, the GLP-1 receptor (GLP-1R) is also present in the kidney, where it influences renal function. The effect of GLP-1 on the kidney varies between humans and rodents. The effect of GLP-1 on kidney function also seems to vary depending on its concentration and the physiological or pathological state of the kidney. In studies with rodents or humans, acute infusion of pharmacological doses of GLP-1 stimulates natriuresis and diuresis. However, the effect on the renal vasculature is less clear. In rodents, GLP-1 infusion increases renal plasma flow and glomerular filtration rate, suggesting renal vasodilation. In humans, only a subset of the study participants exhibits increased renal plasma flow and glomerular filtration rate. Differential status of kidney function and changes in renal vascular resistance of the preglomerular arterioles may account for the different responses of the human study participants. Because renal function in patients with type 2 diabetes is already at risk or compromised, understanding the effects of GLP-1R activation on kidney function in these patients is particularly important. This review examines the distribution of GLP-1R in the kidney and the effects elicited by GLP-1 or GLP-1R agonists. By integrating results from acute and chronic studies in healthy individuals and patients with type 2 diabetes along with those from rodent studies, we provide insight into how GLP-1R activation affects renal function and autoregulation.

Insulin Sensitivity and Renal Hemodynamic Function in Metformin-Treated Adults With Type 2 Diabetes and Preserved Renal Function

OBJECTIVE

Impaired insulin sensitivity is associated with hyperfiltration (i.e., elevated glomerular filtration rate [GFR]) in adolescents with type 2 diabetes (T2D) and adults with prediabetes. Yet, these relationships are based on studies that relied on estimated GFR (eGFR), estimates of insulin sensitivity, or both. We aimed to verify the relationship between insulin sensitivity and renal hemodynamic function by gold standard methods in adults with T2D.

RESEARCH DESIGN AND METHODS

Insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp (M value) (glucose infusion rate in mg/kg_lean/min) and renal hemodynamic function by urinary inulin (GFR) and para-aminohippuric acid (effective renal plasma flow [ERPF]) clearances in participants with T2D without overt kidney disease. Filtration fraction (FF) (GFR/ERPF) was calculated. Relationships between insulin sensitivity and renal hemodynamic parameters were examined by multivariable linear regression. Renal hemodynamic parameters were examined across tertiles of M values.

RESULTS

We tested 44 adults with T2D, of whom 77% were male, with mean ± SD age 63 ± 7 years, BMI 31.2 ± 4.0 kg/m², and HbA_1c 7.4 ± 0.6%. Average GFR was 110 ± 26 mL/min, with an FF of 22.1 ± 2.8% and median 24-h urinary albumin excretion of 11.3 mg (interquartile range 5.8-17.0). Average M value was 5.6 ± 2.9 mg/kg_lean/min. Insulin sensitivity inversely correlated with GFR (r = -0.44, P < 0.01) and FF (r = -0.40, P < 0.01), and these associations remained significant after multivariable adjustments for age, sex, renin-angiotensin system inhibitor use, and HbA_1c. In addition, GFR, FF, and urinary albumin excretion were highest in the participants in the lowest M value tertile.

CONCLUSIONS

For the first time, we demonstrate that impaired insulin sensitivity is associated with intrarenal hemodynamic dysfunction by gold standard techniques in adults with T2D treated with metformin monotherapy.

Increased Glomerular Hydrostatic Pressure is Associated with Tubular Creatinine Reabsorption in Healthy Subjects

<b><i>Background:</i></b> Cr is secreted by the proximal tubules and thus Cr clearance (<i>C</i>_cr) can overestimate inulin clearance (<i>C</i>_in). However, in some cases, <i>C</i>_cr can even underestimate <i>C</i>_in. This suggests that Cr could be reabsorbed in the tubuli. We examined the clinical parameters that are associated with tubular Cr reabsorption. <b><i>Methods:</i></b> In 80 kidney donor candidates (53.9 ± 13.2 years, 29 males), <i>C</i>_in and para-aminohippuric acid clearance were measured simultaneously. Intrarenal hemodynamic parameters were calculated by Gomez’s formulae. To quantify the secretory component of <i>C</i>_cr (SF_cr), it was calculated as follows: SF_cr = (<i>C</i>_cr − <i>C</i>_in)/<i>C</i>_cr. <b><i>Results:</i></b> Twenty-five subjects (31.3%) showed SF_cr values &#x3c;0. SF_cr that correlated significantly and negatively with efferent arteriolar resistance (<i>R</i>_e) and glomerular hydrostatic pressure (<i>P</i>_glo) (<i>R</i>_e: <i>r</i> = −0.30, <i>p</i> = 0.008; <i>P</i>_glo: <i>r</i> = −0.28, <i>p</i> = 0.025). In multiple regression analyses, <i>R</i>_e and <i>P</i>_glo were significantly and negatively associated with SF_cr after adjustment for other confounders. <b><i>Conclusions:</i></b> These findings suggest that tubular reabsorption of Cr can occur in some cases. Intrarenal glomerular hemodynamic burden may be related to tubular creatinine reabsorption, which possibly leads to lower <i>C</i>_cr values.

Combining GLP-1 Receptor Agonists and Basal Insulin in Older Adults with Type 2 Diabetes: Focus on Lixisenatide and Insulin Glargine

Estimates suggest that there are currently 122.8 million adults 65-99 years of age living with diabetes, of whom 90-95% are diagnosed with type 2 diabetes (T2D). Over the past two decades, a greater understanding of the complex and multifactorial pathogenesis of T2D has resulted in the development and introduction of new-generation classes of glucose-lowering therapies, which are now extensively endorsed by prevailing guidelines and are increasingly being used worldwide. These newer agents may further assist in the effective pharmacological management of T2D through the provision of patient-centered care that acknowledges multimorbidity and is respectful of and responsive to individual patient preferences and barriers. Given these considerations, the therapeutic approach in older patients with T2D is complex, particularly in those who have functional dependence, frailty, dementia, or who are at end-of-life. It is currently too early to draw conclusions on the long-term use of newer glucose-lowering agents in this population, as their efficacy and safety in older adults remains largely unknown. In this review, we will discuss considerations for the use of glucose-lowering treatments in older adults, with particular focus on the use of basal insulin and glucagon-like peptide-1 receptor agonists, and the rationale for the use of combination therapy comprising these agents. Finally, we will review clinical data from studies of the fixed-ratio combination of insulin glargine and lixisenatide in older patients with T2D. FUNDING: Sanofi US, Inc.

Review of glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes mellitus in patients with chronic kidney disease and their renal effects

Type 2 diabetes mellitus (T2DM) is the most common cause of chronic kidney disease (CKD), and when it causes CKD it is collectively referred to as diabetic kidney disease. One of the newer therapies for managing hyperglycemia is the glucagon-like peptide-1 receptor agonist (GLP-1RA) drug class. This review summarizes the effects of GLP-1RAs in patients with T2DM with CKD and evidence for renoprotection with GLP-1RAs using data from observational studies, prospective clinical trials, post hoc analyses, and meta-analyses. Evidence from some preclinical studies was also reviewed. Taken together, subgroup analyses of patients with varying degrees of renal function demonstrated that glycemic control with GLP-1RAs was not markedly less effective in patients with mild or moderate renal impairment vs that in patients with normal function. GLP-1RAs were associated with improvements in some cardiorenal risk factors, including systolic blood pressure and body weight. Furthermore, several large cardiovascular outcome studies showed reduced risks of composite renal outcomes, mostly driven by a reduction in macroalbuminuria, suggesting potential renoprotective effects of GLP-1RAs. In conclusion, GLP-1RAs effectively reduced hyperglycemia in patients with mild or moderately impaired kidney function in the limited number of studies to date. GLP-1RAs may be considered in combination with other glucose-lowering medications because of their ability to lower glucose in a glucose-dependent manner, lowering their risk for hypoglycemia, while improving some cardiorenal risk factors. Potential renoprotective effects of GLP-1RAs, and their renal mechanisms of action, warrant further investigation.

The renal hemodynamic effects of the SGLT2 inhibitor dapagliflozin are caused by post-glomerular vasodilatation rather than pre-glomerular vasoconstriction in metformin-treated patients with type 2 diabetes in the randomized, double-blind RED trial

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) improve hard renal outcomes in type 2 diabetes. This is possibly explained by the fact that SGLT2i normalize the measured glomerular filtration rate (mGFR) by increasing renal vascular resistance, as was shown in young people with type 1 diabetes and glomerular hyperfiltration. Therefore, we compared the renal hemodynamic effects of dapagliflozin with gliclazide in type 2 diabetes. The mGFR and effective renal plasma flow were assessed using inulin and para-aminohippurate clearances in the fasted state, during clamped euglycemia (5 mmol/L) and during clamped hyperglycemia (15 mmol/L). Filtration fraction and renal vascular resistance were calculated. Additionally, factors known to modulate renal hemodynamics were measured. In 44 people with type 2 diabetes on metformin monotherapy (Hemoglobin A1c 7.4%, mGFR 113 mL/min), dapagliflozin versus gliclazide reduced mGFR by 5, 10, and 12 mL/min in the consecutive phases while both agents similarly improved Hemoglobin A1c (-0.48% vs -0.65%). Dapagliflozin also reduced filtration fraction without increasing renal vascular resistance, and increased urinary adenosine and prostaglandin concentrations. Gliclazide did not consistently alter renal hemodynamic parameters. Thus, beyond glucose control, SGLT2i reduce mGFR and filtration fraction in type 2 diabetes. The fact that renal vascular resistance was not increased by dapagliflozin suggests that this is due to post-glomerular vasodilation rather than pre-glomerular vasoconstriction.

Consensus Recommendations on GLP-1 RA Use in the Management of Type 2 Diabetes Mellitus: South Asian Task Force

The advent of incretin mimetics such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) has enriched the armamentarium for diabetes management owing to their glycaemic as well as extra-glycaemic benefits. The approval status and availability of this class of drugs vary widely across the globe. Being a relatively newer class of drug with numerous benefits, several national and international guidelines are working towards addressing clinical questions pertaining to the optimal use of GLP-1 RAs for the management of diabetes. Although the newer class of drugs are associated with significant benefits such as patient-centric approach, these drugs demand the providers to be vigilant and knowledgeable about the medication. The South Asian population is at higher risk of type 2 diabetes mellitus (T2DM) because of their genetic predisposition and lifestyle changes. Hence, prevention and management of T2DM and its associated complications in this population are of paramount importance. The current report aims to present an overview of current knowledge on GLP-1 RAs based on pragmatic review of the available clinical evidence. In addition, this report is a consensus of expert endocrinologists representing South Asian countries including India, Pakistan, Bangladesh, Nepal, Sri Lanka, Afghanistan and the Maldives on essential recommendations related to the use of GLP-1 RAs in a real-world scenario.

Glucagon-Like Peptide-1 Receptor Agonists in Adult Patients With Type 2 Diabetes: Review of Cardiovascular Outcome Trials

People with type 2 diabetes are at heightened risk for developing cardiovascular (CV) events. CV disease is the leading cause of premature death among adults with type 2 diabetes. Unfortunately, historically, some antidiabetes agents were implicated in worsening CV function, despite improving glycemic and metabolic control. Accordingly, over a decade ago, health regulatory bodies modified approval requirements for novel antidiabetes pharmacotherapies, requiring prospective evaluation of CV safety through cardiovascular outcome trials (CVOTs). To meet regulatory requirements, CVOTs were primarily designed around establishing CV safety by demonstrating noninferiority to placebo in addition to standard of care, without significant differences in blood glucose. If appropriately designed and powered, however, these CVOTs could also determine superiority, and hence CV protection. Although many of these CVOTs were initiated several years ago, the recent reporting of the results for these CVOTs has been pivotal and practice-changing. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are one such class of antidiabetes therapies, wherein multiple GLP-1RA CVOTs, but interestingly, not all, have demonstrated CV benefits. In this review, we provide a comprehensive summary of all the reported CVOTs completed with GLP-1RAs to date. Although it remains unclear why some GLP-1RAs are associated with reducing CV events, whereas others have been consistent with CV safety alone, we highlight and provide an overview of some key differences between the various GLP-1RAs and their respective CVOTs and possible implications of study design differences. We also speculate on potential mechanisms of action for glucagon-like peptide-1 receptor signalling in the CV system.

The good companions: insulin and glucagon-like peptide-1 receptor agonist in type 2 diabetes. A systematic review and meta-analysis of randomized controlled trials

We provided an updated systematic review with meta-analysis of randomized controlled trials (RCTs) assessing the metabolic effects of combination therapy of insulin and GLP-1RA (combo) in comparison with other injectable therapy. We searched PubMed, Cochrane Register of Controlled Trials, Scholar, and ClinicalTrials.gov for RCTs evaluating changes in HbA1c (primary outcome), proportion of patients at HbA1c target <7%, hypoglycaemia, and weight change (secondary end-points). We included 36 RCTs involving 14,636 patients. Compared with comparator therapies (overall analysis), the combo led to a significant HbA1c reduction (=-0.49%, 95% CI -0.61 to -0.38%, P < 0.001), more patients at HbA1c target [relative risk, (RR) = 1.77, 95% CI, 1.56, 2.01, P < 0.001], similar hypoglycaemic events (RR = 1.03, 95% CI, 0.88, 1.19, P = 0.728), and reduction in body weight (-2.5 Kg, 95% CI -3.1 to -1.8 kg, P < 0.001), with high heterogeneity in each analysis. The quality of the evidence was low for three of the considered outcomes. Compared with intensified insulin regimens (basal-plus/basal-bolus) the combo produced similar glycemic control with reduction of both hypoglycaemia, and body weight. Combination therapy of GLP-1RA and insulin could represent a valuable treatment strategy to improve glycemic control in the management of type 2 diabetes.

Exenatide twice-daily does not affect renal function or albuminuria compared to titrated insulin glargine in patients with type 2 diabetes mellitus: A post-hoc analysis of a 52-week randomised trial

AIMS

To compare the effects of long-term treatment with the GLP-1RA exenatide twice-daily versus titrated insulin glargine (iGlar) on renal function and albuminuria in type 2 diabetes (T2DM) patients.

METHODS

We post-hoc evaluated renal outcome-data of 54 overweight T2DM patients (mean  ± SD age 60 ± 8 years, HbA1c 7.5 ± 0.9%, eGFR 86 ± 16 mL/min/1.73 m², median [IQR] urinary albumin-to-creatinine-ratio (UACR) 0.75 [0.44-1.29] mg/mmol) randomised to exenatide 10 µg twice-daily or titrated iGlar on-top-of metformin for 52-weeks. Renal efficacy endpoints were change in creatinine clearance (CrCl) and albuminuria (urinary albumin-excretion [UAE] and UACR) based on 24-h urines, collected at baseline and Week-52. eGFR and exploratory endpoints were collected throughout the intervention-period, and after a 4-week wash-out.

RESULTS

HbA1c-reductions were similar with exenatide (mean ± SEM -0.80 ± 0.10%) and iGlar (-0.79 ± 0.14%; treatment-difference 0.02%; 95% CI -0.31 to 0.42%). Change from baseline to Week-52 in CrCl, UAE or UACR did not statistically differ; only iGlar reduced albuminuria (P < 0.05; within-group). eGFR decreased from baseline to Week-4 with exenatide (-3.9 ± 2.1 mL/min/1.73 m²; P = 0.069) and iGlar (-2.7 ± 1.2 mL/min/1.73 m²; P = 0.034), without treatment-differences in ensuing trajectory. Exenatide versus iGlar reduced bodyweight (-5.4 kg; 2.9-7.9; P < 0.001), but did not affect blood pressure, lipids or plasma uric acid.

CONCLUSIONS

Among T2DM patients without overt nephropathy, one-year treatment with exenatide twice-daily does not affect renal function-decline or onset/progression of albuminuria compared to titrated iGlar.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT00097500.

New pharmacological strategies for protecting kidney function in type 2 diabetes

Type 2 diabetes is the leading cause of impaired kidney function, albuminuria, and renal replacement therapy globally, thus placing a large burden on health-care systems. Current treatment strategies rely on intensive glucose lowering as well as strict blood pressure control through blockade of the renin-angiotensin-aldosterone system. Such approaches might slow decline in kidney function, but many patients progress to end-stage kidney failure despite optimal therapy. In recent clinical trials, new-generation glucose-lowering drug classes, the sodium-glucose co-transporter-2 inhibitors and agents that target the incretin pathway, have been shown to improve kidney outcomes in patients with type 2 diabetes. Other new approaches, which have been developed on the basis of an improved understanding of the mechanisms that contribute to kidney damage in the context of diabetes, include use of drugs that block endothelin receptors (eg, atrasentan) and non-steroidal mineralocorticoid receptors (eg, finerenone). In this Review, we provide an overview of recent clinical data relevant to these new therapeutic approaches for management of kidney disease in the context of type 2 diabetes.

The Effects of Novel Antidiabetic Drugs on Albuminuria in Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND AND OBJECTIVE

The effects of novel antidiabetic drugs, including sodium-glucose cotransporter 2 (SGLT-2) inhibitors, glucagon-like peptide 1 (GLP-1) receptor agonists, and dipeptidyl peptidase 4 (DPP-4) inhibitors, on albuminuria in patients with type 2 diabetes mellitus (T2DM) are still controversial. Therefore, we performed a meta-analysis to evaluate the effects of novel antidiabetic drugs on albuminuria in patients with T2DM.

METHODS

We conducted a random-effects meta-analysis of randomized controlled trials (RCTs) by searching the MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials databases up to 16 August 2018. The effects of novel antidiabetic drugs on albuminuria were evaluated as percent changes from baseline to follow-up urinary albumin excretion/urinary albumin to creatinine ratio (UAE/UACR) levels in both the intervention and control groups. Data regarding percent changes were used to generate weighted mean differences (WMDs) and 95% confidence intervals (CIs).

RESULTS

In this meta-analysis, 26 RCTs involving 14,929 patients were included. Pooled analysis suggested that SGLT-2 inhibitors (WMD - 26.23%, 95% CI - 35.90 to - 16.56; p < 0.00001) and GLP-1 receptor agonists (WMD - 13.85%, 95% CI - 15.96 to - 11.74; p < 0.00001) were associated with a significant reduction in albuminuria compared with other conventional therapies or placebo. DPP-4 inhibitors (WMD - 6.19%, 95% CI - 14.03 to 1.66; p = 0.12) were not significantly associated with lower albuminuria than other conventional therapies or placebo.

CONCLUSION

This meta-analysis indicates that SGLT-2 inhibitors and GLP-1 receptor agonists were associated with a reduction in albuminuria compared with other conventional therapies or placebo, while DPP-4 inhibitors were not associated with albuminuria-reducing effects compared with other conventional therapies or placebo.

GLP-1 receptor agonist added to insulin versus basal-plus or basal-bolus insulin therapy in type 2 diabetes: A systematic review and meta-analysis

BACKGROUND

Current guidelines recommend that antihyperglycaemic treatment in patients with type 2 diabetes not achieving the HbA_1c target on basal insulin should be intensified with a glucagon-like peptide-1 receptor agonist (GLP-1RA) or basal-plus/basal-bolus (BP/BB) insulin regimen. We conducted a systematic review and meta-analysis to compare the effects of GLP-1RA/insulin combinations versus BP/BB.

METHODS

The review was registered on PROSPERO (CRD42017079547). PubMed, Scopus, CENTRAL, and ClinicalTrials.gov were searched until July 2018. All randomized controlled trials (RCTs) reporting HbA_1c , body weight, daily insulin dose, hypoglycaemic events, and discontinuation due to lack of efficacy were included. A subgroup analysis on different combinations of GLP-1RA and insulin was performed.

RESULTS

Out of 1885 retrieved papers, 13 RCTs were included in the review. Compared with BP/BB, GLP-1RA/insulin combinations were associated with a similar HbA_1c reduction (Δ = -0.06%; 95% confidence interval [CI], -0.14 to 0.02; P = 0.13; I²  = 52%), greater weight loss (Δ = -3.72 kg; 95% CI, -4.49 to -2.95; P < 0.001; I²  = 89%), and lower incidence of hypoglycaemic events (relative risk [RR] = 0.46; 95% CI, 0.38-0.55; P < 0.001; I²  = 99%). The daily insulin dosage among GLP-1RA/insulin users was 30.3 IU/day (95% CI, -41.2 to -19.3; P < 0.001; I²  = 94%), lower than with BP/BB. No difference was found for discontinuation due to lack of efficacy.

CONCLUSIONS

The present review supports treatment intensification with GLP-1RA added to insulin versus BP/BB in uncontrolled type 2 diabetes. This could provide similar antihyperglycaemic efficacy while leading to weight loss and sparing of hypoglycaemia and insulin dose. As a consequence, a considerable number of patients with type 2 diabetes could be potentially shifted from BP/BB to GLP-1RA/insulin combinations.

The incretin pathway as a therapeutic target in diabetic kidney disease: a clinical focus on GLP-1 receptor agonists

Diabetic kidney disease (DKD) remains the main cause for chronic kidney disease (CKD) and end-stage kidney disease (ESKD) worldwide. Both CKD and ESKD lead to major increases in risk of cardiovascular disease and death in people with diabetes. Despite optimal management of lifestyle, glucose levels and hypertension, residual risk remains high, indicating that additional therapies to mitigate the burden of the disease are desired. In past decades, new treatment options for the management of diabetes have emerged, of which some have showed promising renoprotective potential. This review discusses current understanding of the renal effects of glucagon-like peptide receptor agonists and their potential use in prevention and treatment of DKD.

Association of Albuminuria With Intraglomerular Hydrostatic Pressure and Insulin Resistance in Subjects With Impaired Fasting Glucose and/or Impaired Glucose Tolerance

OBJECTIVE

Little is known about the relationships between insulin resistance, intrarenal hemodynamics, and urinary albumin excretion (UAE) in humans with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT). The aim of the current study was to examine intrarenal hemodynamic abnormalities, insulin resistance, and UAE in subjects with IFG or IGT. We hypothesized that intrarenal hemodynamic abnormalities would be associated with insulin resistance.

RESEARCH DESIGN AND METHODS

Fifty-four kidney donors underwent 75-g oral glucose tolerance and inulin and para-aminohippuric acid clearance testing. Insulin sensitivity index (ISI) was evaluated by the Matsuda index. Intrarenal hemodynamic parameters were calculated by the Gomez formulae.

RESULTS

Of the 54 subjects, 33 exhibited IFG or IGT and 31 exhibited normal glucose tolerance (NGT). Glomerular hydrostatic pressure (P_glo) and UAE were significantly higher in the IFG or IGT subjects with obesity (P = 0.015 and 0.0001, respectively). Log ISI correlated significantly and negatively with P_glo (r = -0.351, P = 0.009) in all subjects. In multiple regression analyses among all subjects, log ISI was associated significantly and independently with P_glo (β = -0.316, P = 0.015), after adjustment for age, sex, and systolic blood pressure. Further, BMI (β = 0.517, P = 0.0004), P_glo (β = 0.420, P = 0.004), and log ISI (β = -0.366, P = 0.008) were each associated significantly and independently with UAE after adjustment.

CONCLUSIONS

We demonstrated that increased insulin resistance is associated with increased P_glo and UAE in IFG or IGT subjects. These hemodynamic burdens and insulin resistance may cause injury to the glomeruli even in subjects with IFG or IGT.

Lixisenatide and renal outcomes in patients with type 2 diabetes and acute coronary syndrome: an exploratory analysis of the ELIXA randomised, placebo-controlled trial

BACKGROUND

The results of the ELIXA trial demonstrated the cardiovascular safety of lixisenatide, a short-acting glucagon-like peptide-1 receptor agonist, in patients with type 2 diabetes and acute coronary syndrome. In this exploratory analysis of ELIXA, we investigate the effect of lixisenatide on renal outcomes.

METHODS

ELIXA was a randomised, double-blind, placebo-controlled trial, done at 828 sites in 49 countries. Patients with type 2 diabetes and a recent coronary artery event were randomly assigned (1:1) to a daily subcutaneous injection of lixisenatide (10-20 μg) or volume-matched placebo, in addition to usual care, until at least 844 patients had an adjudicated major adverse cardiovascular event included in the primary outcome. Patients, study staff, and individuals involved in analysis of trial data were masked to treatment assignment. The primary and secondary endpoints of this trial have been reported previously. Here, in an exploratory analysis of ELIXA, we investigated percentage change in urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) according to prespecified albuminuria status at baseline (normoalbuminuria [UACR <30 mg/g]; microalbuminuria [≥30 to ≤300 mg/g]; and macroalbuminuria [>300 mg/g]) using a mixed-effect model with repeated measures. Time to new-onset macroalbuminuria and doubling of serum creatinine were also assessed with Cox proportional hazards models. The ELIXA trial is registered with ClinicalTrials.gov, number NCT01147250, and is completed.

FINDINGS

Of 6068 patients randomly allocated between July 9, 2010, and Aug 2, 2013, baseline UACR data were available for 5978 (99%). Median follow-up time was 108 weeks. 4441 (74%; 2191 assigned to placebo and 2250 assigned to lixisenatide) had normoalbuminuria, 1148 (19%; 596 assigned to placebo and 552 assigned to lixisenatide) had microalbuminuria, and 389 (7%; 207 assigned to placebo and 182 assigned to lixisenatide) had macroalbuminuria. After 108 weeks, the placebo-adjusted least-squares mean percentage change in UACR from baseline with lixisenatide was -1·69% (95% CI -11·69 to 8·30; p=0·7398) in patients with normoalbuminuria, -21·10% (-42·25 to 0·04; p=0·0502) in patients with microalbuminuria, and -39·18% (-68·53 to -9·84; p=0·0070) in patients with macroalbuminuria. Lixisenatide was associated with a reduced risk of new-onset macroalbuminuria compared with placebo when adjusted for baseline HbA_1c (hazard ratio [HR] 0·808 [95% CI 0·660 to 0·991; p=0·0404]) or baseline and on-trial HbA_1c (HR 0·815 [0·665 to 0·999; p=0·0491]); point estimates were similar when adjusted for other traditional renal risk factors. At week 108, the largest eGFR decline from baseline was observed in the macroalbuminuric group, but no significant differences were observed between the two treatment groups. No significant differences in eGFR decline were identified between treatment groups in any UACR subgroup. In the trial safety population, doubling of serum creatinine occurred in 35 (1%) of 3032 patients in the placebo group and 41 (1%) of 3031 patients in the lixisenatide group (HR 1·163, 95% CI 0·741-1·825; p=0·5127). As previously reported in the ELIXA trial, the proportion of patients with renal adverse events was low (48 [1·6%] of 3032 patients in the placebo group vs 48 [1·6%] of 3031 patients in the lixisenatide group) and did not significantly differ between treatment groups.

INTERPRETATION

Lixisenatide reduces progression of UACR in macroalbuminuric patients, and is associated with a lower risk of new-onset macroalbuminuria after adjustment for baseline and on-trial HbA_1c and other traditional renal risk factors.

FUNDING

Sanofi.

Renal tubular effects of prolonged therapy with the GLP-1 receptor agonist lixisenatide in patients with type 2 diabetes mellitus

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are well-established glucose-lowering drugs for type 2 diabetes mellitus (T2DM) management. Acute GLP-1RA administration increases urinary excretion of sodium and other electrolytes. However, the renal tubular effects of prolonged GLP-1RA treatment are largely unknown. In this secondary analysis of a randomized trial, we determined the renal tubular effects of 8-wk treatment with 20 μg lixisenatide, a short-acting (prandial) GLP-1RA, versus titrated once-daily insulin glulisine in 35 overweight T2DM-patients on stable insulin glargine background therapy (age: 62 ± 7 yr, glycated hemoglobin: 8.0 ± 0.9%, estimated glomerular filtration rate: >60 ml·min^-1·1.73 m^-2). After a standardized breakfast, lixisenatide increased absolute and fractional excretions of sodium, chloride, and potassium and increased urinary pH. In contrast, lixisenatide reduced absolute and fractional excretions of magnesium, calcium, and phosphate. At week 8, patients treated with lixisenatide had significantly more phosphorylated sodium-hydrogen exchanger isoform 3 (NHE3) in urinary extracellular vesicles than those on insulin glulisine treatment, which suggested decreased NHE3 activity in the proximal tubule. A rise in postprandial blood pressure with lixisenatide partly explained the changes in the urinary excretion of sodium, potassium, magnesium, and phosphate and the changes in urinary pH. In conclusion, lixisenatide affects postprandial urinary excretion of several electrolytes and increases urinary pH compared with insulin glulisine in T2DM patients after 8 wk of treatment. This is most likely explained by a drug-induced rise in blood pressure or direct inhibitory effects on NHE3 in the proximal tubule.

The Ascending GLP-1 Road From Clinical Safety to Reduction of Cardiovascular Complications

Glucagon-like peptide 1 (GLP-1) was originally identified as a gut-derived incretin hormone that lowered glycemia through potentiation of glucose-dependent insulin secretion. Subsequent studies expanded the actions of GLP-1 to include inhibition of glucagon secretion, gastric emptying, and appetite, collectively useful attributes for a glucose-lowering agent. The introduction of GLP-1 receptor (GLP-1R) agonists for the treatment of diabetes was associated with questions surrounding their safety, principally with regard to medullary thyroid cancer, pancreatitis, and pancreatic cancer, yet cardiovascular outcome trials subsequently revealed reductions in rates of stroke, myocardial infarction, and cardiovascular death with a paucity of major safety signals. We discuss the controversies, unanswered questions, and established use of GLP-1R agonists from a mechanistic and clinical perspective. We highlight methods for detection and cellular sites of GLP-1R expression, key uncertainties, recent insights, and experimental caveats surrounding the use of GLP-1R agonists for the treatment of diabetes and the reduction of diabetes-related complications.

Lixisenatide Versus Insulin Glulisine on Fasting and Postbreakfast Systemic Hemodynamics in Type 2 Diabetes Mellitus Patients

The prolonged treatment effects of a short-acting GLP-1RA (glucagon-like peptide-1 receptor agonist), such as lixisenatide, on fasting and postprandial systemic hemodynamics in type 2 diabetes mellitus patients are unknown. In this secondary analysis, we included 34 overweight insulin glargine-treated type 2 diabetes mellitus patients (mean±SD age, 62±7 years; HbA_1c, 8.0±0.9%; systolic blood pressure [BP], 133.9±16.1 mm Hg; diastolic BP, 75.4±8.39 mm Hg) that were randomized to once-daily lixisenatide 20 μg or once-daily titrated insulin glulisine for 8 weeks. Systemic hemodynamics (oscillometric device and finger photoplethysmography), arterial stiffness (applanation tonometry), and cardiac sympathovagal balance (heart rate variability) were measured in the fasting state and repetitively (up to minute 175) after a standardized mixed breakfast. Acetaminophen was given orally to estimate gastric emptying rate. Lixisenatide did not affect fasting systemic hemodynamics compared with insulin glulisine from baseline to week 8. Postbreakfast overall, lixisenatide compared with insulin glulisine tended to increase systolic BP by 5.2±2.9 mm Hg (P=0.087) and increased diastolic BP by 5.4±1.4 mm Hg (P<0.001), with respective maximal differences of +10.2±3.7 mm Hg (P=0.007) and +7.2±1.5 mm Hg (P<0.001). Lixisenatide increased systemic vascular resistance (P<0.001) and arterial stiffness (P=0.007). No between-group differences in overall postbreakfast heart rate, cardiac output, or cardiac sympathovagal balance, and circulating catecholamines, angiotensin II, or aldosterone were observed. Both treatments lowered HbA_1c similarly, whereas lixisenatide achieved greater reductions in postbreakfast plasma glucose excursions. Lixisenatide slowed gastric emptying rate, which statistically explained changes in postbreakfast BP. Lixisenatide compared with once-daily titrated insulin glulisine for 8 weeks does not affect fasting but increases postbreakfast BP in insulin glargine-treated type 2 diabetes mellitus patients. This effect could, at least in part, be explained by reduced passage rate of nutrients and water and activation of the gastrovascular reflex.

Effect of immediate and prolonged GLP-1 receptor agonist administration on uric acid and kidney clearance: Post-hoc analyses of four clinical trials

AIMS

To determine the effects of glucagon-like peptide (GLP)-1 receptor agonists (RA) on uric acid (UA) levels and kidney UA clearance.

MATERIAL AND METHODS

This study involved post-hoc analyses of 4 controlled clinical trials, which assessed actions of GLP-1RA administration on kidney physiology. The immediate effects of GLP-1RA exenatide infusion vs placebo were determined in 9 healthy overweight men (Study-A) and in 52 overweight T2DM patients (Study-B). The effects of 12 weeks of long-acting GLP-1RA liraglutide vs placebo in 36 overweight T2DM patients (Study-C) and of 8 weeks of short-acting GLP-1RA lixisenatide vs once-daily titrated insulin glulisine in 35 overweight T2DM patients (Study-D) were also examined. Plasma UA, fractional (inulin-corrected) and absolute urinary excretion of UA (UE_UA ) and sodium (UE_Na ), and urine pH were determined.

RESULTS

Median baseline plasma UA level was 5.39 to 6.33 mg/dL across all studies (17%-22% of subjects were hyperuricaemic). In Study-A, exenatide infusion slightly increased plasma UA (+0.07 ± 0.02 mg/dL, P = .04), and raised absolute-UE_UA (+1.58 ± 0.65 mg/min/1.73 m² , P = .02), but did not affect fractional UE_UA compared to placebo. Fractional UE_UA and absolute UE_UA correlated with increases in urine pH (r:0.86, P = .003 and r:0.92, P < .001, respectively). Fractional UE_UA correlated with increased fractional UE_Na (r:0.76, P = .02). In Study-B, exenatide infusion did not affect plasma UA, but increased fractional UE_UA (+0.76 ± 0.38%, P = .049) and absolute UE_UA (+0.75 ± 0.27 mg/min/1.73 m² , P = .007), compared to placebo. In regression analyses, both parameters were explained by changes in urine pH and, in part, by changes in UE_Na . In Study-C, liraglutide treatment did not affect plasma UA, UE_UA, UE_Na or urine pH, compared to placebo. In Study-D, lixisenatide treatment increased UE_Na and urine pH from baseline, but did not affect plasma UA or UE_UA .

CONCLUSION

Immediate exenatide infusion increases UE_UA in overweight healthy men and in T2DM patients, probably by inhibiting Na⁺ /H⁺ -exchanger type-3 in the renal proximal tubule. Prolonged treatment with a long-acting or short-acting GLP-1RA does not affect plasma UA or UE_UA in T2DM patients with normal plasma UA levels and at relatively low cardiovascular risk. Our results suggest that the cardio-renal benefits of GLP-1RA are not mediated through changes in UA.

GLP-1 and the kidney: from physiology to pharmacology and outcomes in diabetes

The gastrointestinal tract - the largest endocrine network in human physiology - orchestrates signals from the external environment to maintain neural and hormonal control of homeostasis. Advances in understanding entero-endocrine cell biology in health and disease have important translational relevance. The gut-derived incretin hormone glucagon-like peptide 1 (GLP-1) is secreted upon meal ingestion and controls glucose metabolism by modulating pancreatic islet cell function, food intake and gastrointestinal motility, amongst other effects. The observation that the insulinotropic actions of GLP-1 are reduced in type 2 diabetes mellitus (T2DM) led to the development of incretin-based therapies - GLP-1 receptor agonists and dipeptidyl peptidase 4 (DPP-4) inhibitors - for the treatment of hyperglycaemia in these patients. Considerable interest exists in identifying effects of these drugs beyond glucose-lowering, possibly resulting in improved macrovascular and microvascular outcomes, including in diabetic kidney disease. As GLP-1 has been implicated as a mediator in the putative gut-renal axis (a rapid-acting feed-forward loop that regulates postprandial fluid and electrolyte homeostasis), direct actions on the kidney have been proposed. Here, we review the role of GLP-1 and the actions of associated therapies on glucose metabolism, the gut-renal axis, classical renal risk factors, and renal end points in randomized controlled trials of GLP-1 receptor agonists and DPP-4 inhibitors in patients with T2DM.