Effects of liraglutide versus sitagliptin on circulating cardiovascular biomarkers, including circulating progenitor cells, in individuals with type 2 diabetes and obesity: Analyses from the LYDIA trial

Liraglutide improves peripheral perfusion and markers of angiogenesis and inflammation in people with type 2 diabetes and peripheral artery disease: An 18-month follow-up of a randomized clinical trial

AIMS

In a six-month randomized clinical trial, improved peripheral perfusion has been shown with liraglutide, associated with favourable vascular effects in people with type 2 diabetes and peripheral artery disease (PAD). We aimed to evaluate the durability of these benefits and to elucidate some mechanisms underlying liraglutide's effect over an 18-month follow-up.

METHODS

STARDUST was a randomized clinical trial which compared liraglutide up to 1.8 mg/day with tailored therapeutic prescriptions to manage cardiovascular risk factors in 55 participants with type 2 diabetes and PAD. We report data of people who have reached the 18-month follow-up for the primary outcome (transcutaneous oxygen pressure, TcPO2) and also for additional secondary outcomes (markers of inflammation, angiogenesis and kidney function), as well as glycemic and metabolic parameters. TcPO2 was assessed with transcutaneous oximetry. Circulating levels of angiogenic progenitor cells and serum inflammation markers were evaluated by flow cytometry and enzyme-linked immunosorbent assay, respectively.

RESULTS

Compared with the control group, significant differences favouring the liraglutide group were observed at 18 months for TcPO2 [estimated treated difference (95% CI), 10.9 mmHg (7.6 to 14.1 mmHg), p < 0.001]. At 18 months of follow-up, participants in the liraglutide group, as compared with those in the control group, had a significant reduction in urine albumin to creatinine ratio (estimated difference, -103.9 mg/g Cr, 95%CI, -170.8 to -37.1, p = 0.003), C-reactive protein (-0.5 mg/dL, 95%CI, -0.8 to -0.2, p = 0.002), as well as interleukin-6 (-32.6 pg/mL, 95%CI, -54.6 to -10.5, p = 0.004). Compared with the control group, participants in the liraglutide group showed significantly higher concentrations of circulating progenitor cells and endothelial progenitor cells at both 6 and 18 months, for CD34+, CD133+, KDR+, CD34+/KDR+ and CD34+/CD133+/KDR+. Liraglutide was also associated with a higher increase in vascular endothelial growth factor A at 18 months (70.1 pg/mL, 95%CI, 44.7 to 95.4, p < 0.001).

CONCLUSIONS

In people with type 2 diabetes and PAD, liraglutide increased peripheral perfusion, with amelioration of markers of angiogenesis and inflammation over an 18-month follow-up.

The effect of GLP-1 receptor agonists on circulating inflammatory markers in type 2 diabetes patients: A systematic review and meta-analysis

AIM

To investigate whether the antidiabetic agent glucagon-like peptide-1 receptor agonists (GLP-1 RAs) can exert anti-inflammatory effects while lowering blood glucose, we performed a meta-analysis and systematic review.

METHODS

We searched 4 online databases (Medline, Embase, Cochrane Library and the Web of Science) for randomised controlled trials (RCTs) that examined changes after GLP-1RAs intervention in commonly accepted biomarkers of inflammation: C-reactive protein (CRP), tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), leptin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), monocyte chemotactic protein-1(MCP-1) and advanced glycation end products (AGEs).

RESULTS

This meta-analysis included 52 eligible RCTs (n = 4734) with a median follow-up of 24 weeks, a mean age of 54.13 years, 44.46% females, body mass index (BMI) 29.80 kg/m2, glycated haemoglobin (HbA1c) 8.28% and diabetes duration 7.27 years. GLP-1 RAs treatment, compared to placebo or conventional diabetes therapies (including oral medicine and insulin), resulted in significant reductions in CRP, TNF-α, IL-6, IL-1β and leptin (standard mean difference [SMD] -0.63 [-1.03, -0.23]; SMD -0.92 [-1.57, -0.27]; SMD -0.76 [-1.32, -0.20], SMD -3.89 [-6.56, -1.22], SMD -0.67 [-1.09, -0.26], respectively), as well as significant increases in adiponectin (SMD 0.69 [0.19, 1.19]).

CONCLUSIONS

Our meta-analysis demonstrates that GLP-1 RAs exert significant anti-inflammatory effects in patients with T2DM. Our findings provide important insights that may guide the therapeutic application of GLP-1 RAs and inform the development of related therapies.

Impact of DPP-4 Inhibitors on Interleukin Levels in Type 2 Diabetes Mellitus

BACKGROUND AND OBJECTIVE

Accumulating evidence had implicated pathological involvement of interleukins (ILs) in progression and complications in patients with type 2 diabetes mellitus (T2DM). Dipeptidyl peptidase-4 inhibitors (DPP-4i) produced favorable effects on glucose homeostasis in T2DM. This study aimed to evaluate the impact of DPP-4i on IL concentrations in T2DM.

DATA SOURCES

PubMed, Embase, and the Cochrane library were systematically searched for relevant articles from inception to May 31, 2024. The search included DPP-4i, T2DM, and randomized controlled trials (RCTs) and related terms.

STUDY SELECTION AND DATA EXTRACTION

Placebo- or active agents-controlled human studies were screened. All the RCTs were identified if they provided detailed information on changes of ILs during DPP-4i treatment.

DATA SYNTHESIS

A total of 14 RCTs involving 850 participants were identified. Pooled estimates revealed that DPP-4i significantly lowered IL-6 concentrations (-0.54 pg/mL; 95% CI, -0.82 to -0.25; I2 = 10%, P = .0003) compared to placebo. Similar effects were demonstrated for IL-1β (-16.33 pg/mL; 95% CI, -19.56 to -13.11; I2 = 0%, P < .00001), whereas the effect on IL-18 was not statistically significant (-13.55 pg/mL; 95% CI, -76.95 to 49.85; I2 = 0%, P = .68). Subgroup analysis on IL-6 demonstrated that marked effects were found in groups of basal IL-6 concentrations (< 5 pg/mL), body mass index (≥ 28 kg/m2) and type of DPP-4i (linagliptin).

CONCLUSION

DPP-4i favorably decreased IL-6 levels in patients with T2DM. The impact of DPP-4i on IL-1β and IL-18 needed to be explored with more studies. Further trials should be performed to elucidate this anti-inflammatory effect of DPP-4i during treatment of T2DM.

Shared signaling pathways and comprehensive therapeutic approaches among diabetes complications

The growing global prevalence of diabetes mellitus (DM), along with its associated complications, continues to rise. When clinically detected most DM complications are irreversible. It is therefore crucial to detect and address these complications early and systematically in order to improve patient care and outcomes. The current clinical practice often prioritizes DM complications by addressing one complication while overlooking others that could occur. It is proposed that the commonly targeted cell types including vascular cells, immune cells, glial cells, and fibroblasts that mediate DM complications, might share early responses to diabetes. In addition, the impact of one complication could be influenced by other complications. Recognizing and focusing on the shared early responses among DM complications, and the impacted cellular constituents, will allow to simultaneously address all DM-related complications and limit adverse treatment impacts. This review explores the current understanding of shared pathological signaling mechanisms among DM complications and recognizes new concepts that will benefit from further investigation in both basic and clinical settings. The ultimate goal is to develop more comprehensive treatment strategies, which effectively impact DM complications in multiple organs and improve patient care and outcomes.

Liraglutide Improves Myocardial Perfusion and Energetics and Exercise Tolerance in Patients With Type 2 Diabetes

BACKGROUND

Type 2 diabetes (T2D) is characterized by insulin resistance (IR) and dysregulated insulin secretion. Glucagon-like peptide-1 receptor agonist liraglutide promotes insulin secretion, whereas thiazolidinedione-pioglitazone decreases IR.

OBJECTIVES

This study aimed to compare the efficacies of increasing insulin secretion vs decreasing IR strategies for improving myocardial perfusion, energetics, and function in T2D via an open-label randomized crossover trial.

METHODS

Forty-one patients with T2D (age 63 years [95% CI: 59-68 years], 27 [66%] male, body mass index 27.8 kg/m2) [95% CI: 26.1-29.5 kg/m2)]) without cardiovascular disease were randomized to liraglutide or pioglitazone for a 16-week treatment followed by an 8-week washout and a further 16-week treatment with the second trial drug. Participants underwent rest and dobutamine stress 31phosphorus magnetic resonance spectroscopy and cardiovascular magnetic resonance for measuring the myocardial energetics index phosphocreatine to adenosine triphosphate ratio, myocardial perfusion (rest, dobutamine stress myocardial blood flow, and myocardial perfusion reserve), left ventricular (LV) volumes, systolic and diastolic function (mitral in-flow E/A ratio), before and after treatment. The 6-minute walk-test was used for functional assessments.

RESULTS

Pioglitazone treatment resulted in significant increases in LV mass (96 g [95% CI: 68-105 g] to 105 g [95% CI: 74-115 g]; P = 0.003) and mitral-inflow E/A ratio (1.04 [95% CI: 0.62-1.21] to 1.34 [95% CI: 0.70-1.54]; P = 0.008), and a significant reduction in LV concentricity index (0.79 mg/mL [95% CI: 0.61-0.85 mg/mL] to 0.73 mg/mL [95% CI: 0.56-0.79 mg/mL]; P = 0.04). Liraglutide treatment increased stress myocardial blood flow (1.62 mL/g/min [95% CI: 1.19-1.75 mL/g/min] to 2.08 mL/g/min [95% CI: 1.57-2.24 mL/g/min]; P = 0.01) and myocardial perfusion reserve (2.40 [95% CI: 1.55-2.68] to 2.90 [95% CI: 1.83-3.18]; P = 0.01). Liraglutide treatment also significantly increased the rest (1.47 [95% CI: 1.17-1.58] to 1.94 [95% CI: 1.52-2.08]; P =0.00002) and stress phosphocreatine to adenosine triphosphate ratio (1.32 [95% CI: 1.05-1.42] to 1.58 [95% CI: 1.19-1.71]; P = 0.004) and 6-minute walk distance (488 m [95% CI: 458-518 m] to 521 m [95% CI: 481-561 m]; P = 0.009).

CONCLUSIONS

Liraglutide treatment resulted in improved myocardial perfusion, energetics, and 6-minute walk distance in patients with T2D, whereas pioglitazone showed no effect on these parameters (Lean-DM [Targeting Beta-cell Failure in Lean Patients With Type 2 Diabetes]; NCT04657939).

Restoration of blood vessel regeneration in the era of combination SGLT2i and GLP-1RA therapy for diabetes and obesity

Ischaemic cardiovascular diseases, including peripheral and coronary artery disease, myocardial infarction, and stroke, remain major comorbidities for individuals with type 2 diabetes (T2D) and obesity. During cardiometabolic chronic disease (CMCD), hyperglycaemia and excess adiposity elevate oxidative stress and promote endothelial damage, alongside an imbalance in circulating pro-vascular progenitor cells that mediate vascular repair. Individuals with CMCD demonstrate pro-vascular 'regenerative cell exhaustion' (RCE) characterized by excess pro-inflammatory granulocyte precursor mobilization into the circulation, monocyte polarization towards pro-inflammatory vs. anti-inflammatory phenotype, and decreased pro-vascular progenitor cell content, impairing the capacity for vessel repair. Remarkably, targeted treatment with the sodium-glucose cotransporter-2 inhibitor (SGLT2i) empagliflozin in subjects with T2D and coronary artery disease, and gastric bypass surgery in subjects with severe obesity, has been shown to partially reverse these RCE phenotypes. SGLT2is and glucagon-like peptide-1 receptor agonists (GLP-1RAs) have reshaped the management of individuals with T2D and comorbid obesity. In addition to glucose-lowering action, both drug classes have been shown to induce weight loss and reduce mortality and adverse cardiovascular outcomes in landmark clinical trials. Furthermore, both drug families also act to reduce systemic oxidative stress through altered activity of overlapping oxidase and antioxidant pathways, providing a putative mechanism to augment circulating pro-vascular progenitor cell content. As SGLT2i and GLP-1RA combination therapies are emerging as a novel therapeutic opportunity for individuals with poorly controlled hyperglycaemia, potential additive effects in the reduction of oxidative stress may also enhance vascular repair and further reduce the ischaemic cardiovascular comorbidities associated with T2D and obesity.

The Impact of Modern Anti-Diabetic Treatment on Endothelial Progenitor Cells

Diabetes is one of the leading chronic diseases globally with a significant impact on mortality. This condition is associated with chronic microvascular and macrovascular complications caused by vascular damage. Recently, endothelial progenitor cells (EPCs) raised interest due to their regenerative properties. EPCs are mononuclear cells that are derived from different tissues. Circulating EPCs contribute to regenerating the vessel's intima and restoring vascular function. The ability of EPCs to repair vascular damage depends on their number and functionality. Diabetic patients have a decreased circulating EPC count and impaired EPC function. This may at least partially explain the increased risk of diabetic complications, including the increased cardiovascular risk in these patients. Recent studies have confirmed that many currently available drugs with proven cardiovascular benefits have beneficial effects on EPC count and function. Among these drugs are also medications used to treat different types of diabetes. This manuscript aims to critically review currently available evidence about the ways anti-diabetic treatment affects EPC biology and to provide a broader context considering cardiovascular complications. The therapies that will be discussed include lifestyle adjustments, metformin, sulphonylureas, gut glucosidase inhibitors, thiazolidinediones, dipeptidyl peptidase 4 inhibitors, glucagon-like peptide 1 receptor analogs, sodium-glucose transporter 2 inhibitors, and insulin.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

Diabetes mellitus (DM) constitutes a chronic metabolic disease characterized by elevated levels of blood glucose which can also lead to the so-called diabetic vascular complications (DVCs), responsible for most of the morbidity, hospitalizations and death registered in these patients. Currently, different approaches to prevent or reduce DM and its DVCs have focused on reducing blood sugar levels, cholesterol management or even changes in lifestyle habits. However, even the strictest glycaemic control strategies are not always sufficient to prevent the development of DVCs, which reflects the need to identify reliable biomarkers capable of predicting further vascular complications in diabetic patients. Endothelial progenitor cells (EPCs), widely known for their potential applications in cell therapy due to their regenerative properties, may be used as differential markers in DVCs, considering that the number and functionality of these cells are affected under the pathological environments related to DM. Besides, drugs commonly used with DM patients may influence the level or behaviour of EPCs as a pleiotropic effect that could finally be decisive in the prognosis of the disease. In the current review, we have analysed the relationship between diabetes and DVCs, focusing on the potential use of EPCs as biomarkers of diabetes progression towards the development of major vascular complications. Moreover, the effects of different drugs on the number and function of EPCs have been also addressed.

Liraglutide alleviates myocardial ischemia‒reperfusion injury in diabetic mice

Diabetic patients are prone to acute myocardial infarction. Although reperfusion therapy can preserve the viability of the myocardium, it also causes fatal ischemia‒reperfusion injury. Diabetes can exacerbate myocardial ischemia‒reperfusion injury, but the mechanism is unclear. We aimed to characterize the effects of liraglutide on the prevention of ischemia‒reperfusion injury and inadequate autophagy. Liraglutide reduced the myocardial infarction area and improved cardiac function in diabetic mice. We further demonstrated that liraglutide mediated these protective effects by activating AMPK/mTOR-mediated autophagy. Liraglutide markedly increased p-AMPK levels and the LC3 II/LC3 I ratio and reduced p-mTOR levels and p62 expression. Pharmacological inhibition of mTOR increased cell viability and autophagy levels in high glucose and H/R-treated H9C2 cells. Overall, our study reveals that liraglutide acts upstream of the AMPK/mTOR pathway to effectively counteract high glucose- and H/R-induced cell dysfunction by activating AMPK/mTOR-dependent autophagy, providing a basis for the clinical prevention and treatment of ischemia‒reperfusion in diabetes.

Evaluation of antiobesity and hepatorenal protective activities of Salvia officinalis extracts pre-treatment in high-fat diet-induced obese rats

The present study evaluated the effects of Hail Salvia officinalis total extract (SOTE) and its high flavonoid fraction (SOHFF) on the high-fat diet (HFD)-induced obesity and hepatorenal damage in rats. Salvia officinalis plants were collected from Hail region, Saudi Arabia. Rats were fed HFD and supplemented orally with SOTE (250 mg kg^-1) or SOHFF (100 mg kg^-1) or simvastatin (SVS; 10 mg kg^-1) every day for 8 weeks. Compared to the controls, HFD-induced obesity led to significant increases in body weight, body weight gained, blood insulin, leptin, cardiac enzymes (LDH and CPK) activity, and atherogenic index (AI). HFD rats also showed higher levels of hepatic and renal function biomarkers (ALT, urea, and creatinine), as well as lower levels of PPARγ and Nrf2-gene expression and a disrupted lipid profile. Moreover, HFD rats had lower levels of hepatic and renal antioxidant biomarkers (CAT, GPx, SOD, GR, and GSH), accompanied by higher levels of hepatic and renal lipid peroxidation (LPO), nitric oxide (NO), and inflammatory mediators (interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)). In addition, histological examination of hepatic and renal tissues revealed histopathological changes that validated the biochemical findings. Compared to HFD group, SOTE and SOHFF treatment led to marked amelioration of all the aforementioned parameters. Collectively, supplementation with SOTE and SOHFF effectively reversed HFD-induced alterations through its antioxidant, hypolipidemic, and anti-inflammatory properties. Hence, SOTE and SOHFF have therapeutic potential in controlling obesity and related pathologies.

Impact of semaglutide on high-sensitivity C-reactive protein: exploratory patient-level analyses of SUSTAIN and PIONEER randomized clinical trials

Background

Exploratory analysis to determine the effect of semaglutide versus comparators on high-sensitivity C-reactive protein (hsCRP) in subjects with type 2 diabetes.

Methods

Trials of once-weekly subcutaneous (SUSTAIN 3) and once-daily oral (PIONEER 1, 2, 5) semaglutide with hsCRP data were analyzed. Subjects with type 2 diabetes (N = 2482) received semaglutide (n = 1328) or comparators (placebo, n = 339; exenatide extended-release, n = 405; empagliflozin, n = 410). hsCRP ratio to baseline at end-of-treatment was analyzed overall, by clinical cutoff (< 1.0, ≥ 1.0 to ≤ 3.0, or > 3.0 mg/L), by tertile, and by estimated glomerular filtration rate in PIONEER 5 (a trial which was conducted in a population with type 2 diabetes and chronic kidney disease [CKD]). Mediation analyses assessed the effect of change in glycated hemoglobin (HbA_1c) and/or change in body weight (BW) on hsCRP reductions.

Results

Geometric mean baseline hsCRP was similar across trials (range 2.7–3.0 mg/L). Semaglutide reduced hsCRP levels by clinical cutoffs and tertiles from baseline to end-of-treatment in all trials versus comparators (estimated treatment ratios [ETRs] versus comparators: 0.70–0.76; p < 0.01) except versus placebo in PIONEER 5 (ETR [95% CI]: 0.83 [0.67–1.03]; p > 0.05). The effect of semaglutide on hsCRP was partially mediated (20.6–61.8%) by change in HbA_1c and BW.

Conclusions

Semaglutide reduced hsCRP ratios-to-baseline versus comparators in subjects with type 2 diabetes (not significant with CKD). This effect was partially mediated via reductions in HbA_1c and BW and potentially by a direct effect of semaglutide. Semaglutide appears to have an anti-inflammatory effect, which is being further investigated in ongoing trials.

Trial registrations: ClinicalTrials.gov identifiers: NCT01885208 (first registered June 2013), NCT02906930 (first registered September 2016), NCT02863328 (first registered August 2016), NCT02827708 (first registered July 2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01585-7.

Obesity and Endothelial Function

Obesity is a major public health problem and is related to increasing rates of cardiovascular morbidity and mortality. Over 1.9 billion adults are overweight or obese worldwide and the prevalence of obesity is increasing. Obesity influences endothelial function through obesity-related complications such as hypertension, dyslipidemia, diabetes, metabolic syndrome, and obstructive sleep apnea syndrome. The excess fat accumulation in obesity causes adipocyte dysfunction and induces oxidative stress, insulin resistance, and inflammation leading to endothelial dysfunction. Several anthropometric indices and imaging modalities that are used to evaluate obesity have demonstrated an association between obesity and endothelial function. In the past few decades, there has been great focus on the mechanisms underlying endothelial dysfunction caused by obesity for the prevention and treatment of cardiovascular events. This review focuses on pathophysiological mechanisms of obesity-induced endothelial dysfunction and therapeutic targets of obesity.

Chemical characterization and DPP-IV inhibitory activity evaluation of tripeptides from Gynura divaricata (L.) DC

ETHNOPHARMACOLOGICAL RELEVANCE

Gynura divaricata (L.) DC. (GD), a herbal medicine, has been used for the prevention and treatment of hyperglycemia in China. However, hypoglycemic ingredients within GD have not yet been well studied.

AIM OF THE STUDY

The aim of this study was to explore undiscovered compounds with dipeptidyl peptidase IV (DPP-IV) inhibitory activity within GD.

MATERIALS AND METHODS

A four-step strategy was developed to explore undiscovered DPP-IV inhibitors within GD. First, the components were preliminarily characterized using UHPLC-HRMS combined with a library search. Second, preliminarily characterized compounds were searched for potential bioactivity. Third, a mixture of these preliminarily characterized compounds was isolated and thoroughly characterized based on fragmentation patterns associated with molecular networking. Fourth, the activities of these compounds were verified using DPP-IV inhibitory assay and molecular docking.

RESULTS

Diprotin A, a tripeptide inhibitor against DPP-IV, was identified. Thereafter, a mixture of twenty-five diprotin A analogs was isolated and characterized, which exhibited IC50 of 0.40 mg/mL for DPP-IV. Molecular docking results also confirmed the interactions between the tripeptide analogs and DPP-IV mainly via H-bonds and hydrophobic interactions.

CONCLUSIONS

This is the first report of DPP-IV inhibitors within GD. These findings demonstrate that the extract of GD might be beneficial for the treatment of type 2 diabetes mellitus, and is expected to promote further development and utilization of GD in herbal medicine.

Cardiovascular and Renal Effectiveness of GLP-1 Receptor Agonists vs. Other Glucose-Lowering Drugs in Type 2 Diabetes: A Systematic Review and Meta-Analysis of Real-World Studies

Cardiovascular outcome trials (CVOT) showed that treatment with glucagon-like peptide-1 receptor agonists (GLP-1RA) is associated with significant cardiovascular benefits. However, CVOT are scarcely representative of everyday clinical practice, and real-world studies could provide clinicians with more relatable evidence. Here, literature was thoroughly searched to retrieve real-world studies investigating the cardiovascular and renal outcomes of GLP-1RA vs. other glucose-lowering drugs and carry out relevant meta-analyses thereof. Most real-world studies were conducted in populations at low cardiovascular and renal risk. Of note, real-world studies investigating cardio-renal outcomes of GLP-1RA suggested that initiation of GLP-1RA was associated with a greater benefit on composite cardiovascular outcomes, MACE (major adverse cardiovascular events), all-cause mortality, myocardial infarction, stroke, cardiovascular death, peripheral artery disease, and heart failure compared to other glucose-lowering drugs with the exception of sodium-glucose transporter-2 inhibitors (SGLT-2i). Initiation of SGLT-2i and GLP-1RA yielded similar effects on composite cardiovascular outcomes, MACE, stroke, and myocardial infarction. Conversely, GLP-1RA were less effective on heart failure prevention compared to SGLT-2i. Finally, the few real-world studies addressing renal outcomes suggested a significant benefit of GLP-1RA on estimated glomerular filtration rate (eGFR) reduction and hard renal outcomes vs. active comparators except SGLT-2i. Further real-world evidence is needed to clarify the role of GLP-1RA in cardio-renal protection among available glucose-lowering drugs.