GLP-1 receptor agonist improves metabolic disease in a pre-clinical model of lipodystrophy.

Aims: Individuals with lipodystrophies typically suffer from metabolic disease linked to adipose tissue dysfunction including lipoatrophic diabetes. In the most severe forms of lipodystrophy, congenital generalised lipodystrophy, adipose tissue may be almost entirely absent. Better therapies for affected individuals are urgently needed. Here we performed the first detailed investigation of the effects of a glucagon like peptide-1 receptor (GLP-1R) agonist in lipoatrophic diabetes, using mice with generalised lipodystrophy. Methods: Lipodystrophic insulin resistant and glucose intolerant seipin knockout mice were treated with the GLP-1R agonist liraglutide either acutely preceding analyses of insulin and glucose tolerance or chronically prior to metabolic phenotyping and ex vivo studies. Results: Acute liraglutide treatment significantly improved insulin, glucose and pyruvate tolerance. Once daily injection of seipin knockout mice with liraglutide for 14 days led to significant improvements in hepatomegaly associated with steatosis and reduced markers of liver fibrosis. Moreover, liraglutide enhanced insulin secretion in response to glucose challenge with concomitantly improved glucose control. Conclusions: GLP-1R agonist liraglutide significantly improved lipoatrophic diabetes and hepatic steatosis in mice with generalised lipodystrophy. This provides important insights regarding the benefits of GLP-1R agonists for treating lipodystrophy, informing more widespread use to improve the health of individuals with this condition.

Glucagon-like peptide-1 analogs activate AMP kinase leading to reversal of the Warburg metabolic switch in breast cancer cells.

Breast cancer (BC) is associated with type 2 diabetes mellitus (T2DM) and obesity. Glucagon-like peptide (GLP)-1 regulates post-prandial insulin secretion, satiety, and gastric emptying. Several GLP-1 analogs have been FDA-approved for the treatment of T2DM and obesity. Moreover, GLP-1 regulates various metabolic activities across different tissues by activating metabolic signaling pathways like adenosine monophosphate (AMP) activated protein kinase (AMPK), and AKT. Rewiring metabolic pathways is a recognized hallmark of cancer, regulated by several cancer-related pathways, including AKT and AMPK. As GLP-1 regulates AKT and AMPK, we hypothesized that it alters BC cells' metabolism, thus inhibiting proliferation. The effect of the GLP-1 analogs exendin-4 (Ex4) and liraglutide on viability, AMPK signaling and metabolism of BC cell lines were assessed. Viability of BC cells was evaluated using colony formation and MTT/XTT assays. Activation of AMPK and related signaling effects were evaluated using western blot. Metabolism effects were measured for glucose, lactate and ATP. Exendin-4 and liraglutide activated AMPK in a cAMP-dependent manner. Blocking Ex4-induced activation of AMPK by inhibition of AMPK restored cell viability. Interestingly, Ex4 and liraglutide reduced the levels of glycolytic metabolites and decreased ATP production, suggesting that GLP-1 analogs impair glycolysis. Notably, inhibiting AMPK reversed the decline in ATP levels, highlighting the role of AMPK in this process. These results establish a novel signaling pathway for GLP-1 in BC cells through cAMP and AMPK modulation affecting proliferation and metabolism. This study suggests that GLP-1 analogs should be considered for diabetic patients with BC.

Liraglutide-associated depression in a patient with type 2 diabetes: A case report and discussion.

BACKGROUND: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) like liraglutide are primarily used for managing blood sugar levels in type 2 diabetes and aiding weight loss. Typically, their adverse effects are gastrointestinal, with limited exploration into their impact on mental health. CASE PRESENTATION: This report examines a 39-year-old male with type 2 diabetes who developed depressive symptoms after starting liraglutide for glycemic control and weight reduction. Symptoms included poor mood, irritability, decreased interest and energy, progressing to sadness, low self-esteem, and physical discomfort. A clinical diagnosis of a depressive episode was made, coinciding with the initiation of liraglutide. INTERVENTION AND OUTCOME: The patient depressive symptoms significantly improved within a week after discontinuing liraglutide and starting antidepressant therapy. This suggests a possible link between liraglutide and depression, despite considering other factors like diabetes-related stress. DISCUSSION: The report explores potential mechanisms, such as GLP-1RA effects on glucose fluctuations and dopamine modulation, which might contribute to depressive symptoms. The influence on the brain reward system and the reduction in cravings for addictive substances after GLP-1RA use is also discussed as a factor in mood regulation. CONCLUSION: This case highlights the necessity of being vigilant about potential psychiatric side effects, particularly depression, associated with GLP-1RAs. The rarity of such reports calls for more research to investigate and understand these implications further.

Glucagon-like peptide 1 agonists for type 2 diabetes, weight loss, or both?

ABSTRACT: Glucagon-like peptide 1 agonists (GLP1s) and the novel glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 agonist are effective drugs for reducing A1C and weight in patients with type 2 diabetes. However, clinicians may find it difficult to discern which drug to prescribe in specific clinical scenarios. This article discusses evidence-based clinical use of these drugs.

Liraglutide and Naringenin relieve depressive symptoms in mice by enhancing Neurogenesis and reducing inflammation.

Depression is a debilitating mental disease that negatively impacts individuals' lives and society. Novel hypotheses have been recently proposed to improve our understanding of depression pathogenesis. Impaired neuroplasticity and upregulated neuro-inflammation add-on to the disturbance in monoamine neurotransmitters and therefore require novel anti-depressants to target them simultaneously. Recent reports demonstrate the antidepressant effect of the anti-diabetic drug liraglutide. Similarly, the natural flavonoid naringenin has shown both anti-diabetic and anti-depressant effects. However, the neuro-pharmacological mechanisms underlying their actions remain understudied. The study aims to evaluate the antidepressant effects and neuroprotective mechanisms of liraglutide, naringenin or a combination of both. Depression was induced in mice by administering dexamethasone (32 mcg/kg) for seven consecutive days. Liraglutide (200 mcg/kg), naringenin (50 mg/kg) and a combination of both were administered either simultaneously or after induction of depression for twenty-eight days. Behavioral and molecular assays were used to assess the progression of depressive symptoms and biomarkers. Liraglutide and naringenin alone or in combination alleviated the depressive behavior in mice, manifested by decrease in anxiety, anhedonia, and despair. Mechanistically, liraglutide and naringenin improved neurogenesis, decreased neuroinflammation and comparably restored the monoamines levels to that of the reference drug escitalopram. The drugs protected mice from developing depression when given simultaneously with dexamethasone. Collectively, the results highlight the usability of liraglutide and naringenin in the treatment of depression in mice and emphasize the different pathways that contribute to the pathogenesis of depression.

Dietary salt promotes cognition impairment through GLP-1R/mTOR/p70S6K signaling pathway.

Dietary salt has been associated with cognitive impairment in mice, possibly related to damaged synapses and tau hyperphosphorylation. However, the mechanism underlying how dietary salt causes cognitive dysfunction remains unclear. In our study, either a high-salt (8%) or normal diet (0.5%) was used to feed C57BL/6 mice for three months, and N2a cells were cultured in normal medium, NaCl medium (80 mM), or NaCl (80 mM) + Liraglutide (200 nM) medium for 48 h. Cognitive function in mice was assessed using the Morris water maze and shuttle box test, while anxiety was evaluated by the open field test (OPT). Western blotting (WB), immunofluorescence, and immunohistochemistry were utilized to assess the level of Glucagon-like Peptide-1 receptor (GLP-1R) and mTOR/p70S6K pathway. Electron microscope and western blotting were used to evaluate synapse function and tau phosphorylation. Our findings revealed that a high salt diet (HSD) reduced the level of synaptophysin (SYP) and postsynaptic density 95 (PSD95), resulting in significant synaptic damage. Additionally, hyperphosphorylation of tau at different sites was detected. The C57BL/6 mice showed significant impairment in learning and memory function compared to the control group, but HSD did not cause anxiety in the mice. In addition, the level of GLP-1R and autophagy flux decreased in the HSD group, while the level of mTOR/p70S6K was upregulated. Furthermore, liraglutide reversed the autophagy inhibition of N2a treated with NaCl. In summary, our study demonstrates that dietary salt inhibits the GLP-1R/mTOR/p70S6K pathway to inhibit autophagy and induces synaptic dysfunction and tau hyperphosphorylation, eventually impairing cognitive dysfunction.

Liraglutide and not lifestyle intervention reduces soluble CD163 after comparable weight loss in obese participants with prediabetes or type 2 diabetes mellitus.

BACKGROUND: The GLP-1 receptor agonist liraglutide is used to treat hyperglycemia in type 2 diabetes but is also known to induce weight loss, preserve the beta cell and reduce cardiovascular risk. The mechanisms underlying these effects are however still not completely known. Herein we explore the effect of liraglutide on markers of immune cell activity in a population of obese individuals with prediabetes or newly diagnosed type 2 diabetes mellitus. METHOD: Plasma levels of the monocyte/macrophage markers, soluble (s)CD163 and sCD14, the neutrophil markers myeloperoxidase (MPO) and neutrophil gelatinase-associated lipocalin (NGAL),the T-cell markers sCD25 and T-cell immunoglobulin mucin domain-3 (sTIM-3) and the inflammatory marker TNF superfamily (TNFSF) member 14 (LIGHT/TNFSF14) were measured by enzyme-linked immunosorbent assays in obese individuals with prediabetes or diabetes diagnosed within the last 12 months, prior to and after comparable weight loss achieved with lifestyle changes (n = 20) or liraglutide treatment (n = 20), and in healthy subjects (n = 13). RESULTS: At baseline, plasma levels of the macrophage marker sCD163, and the inflammatory marker LIGHT were higher in cases as compared to controls. Plasma levels of sCD14, NGAL, sTIM-3 and sCD25 did not differ at baseline between patients and controls. After weight reduction following lifestyle intervention or liraglutide treatment, sCD163 decreased significantly in the liraglutide group vs. lifestyle (between-group difference p = 0.023, adjusted for visceral adipose tissue and triglycerides basal values). MPO and LIGHT decreased significantly only in the liraglutide group (between group difference not significant). Plasma levels of MPO and in particular sCD163 correlated with markers of metabolic dysfunction and inflammation. After weight loss, only sCD163 showed a trend for decreased levels during OGTT, both in the whole cohort as in those of liraglutide vs lifestyle group. CONCLUSION: Weight loss following treatment with liraglutide was associated with reduced circulating levels of sCD163 when compared to the same extent of weight loss after lifestyle changes. This might contribute to reduced cardiometabolic risk in individuals receiving treatment with liraglutide.

Liraglutide promotes UCP1 expression and lipolysis of adipocytes by promoting the secretion of irisin from skeletal muscle cells.

Although Liraglutide (Lira) increases serum irisin levels in type 2 diabetes mellitus (T2DM), it is unclear whether it induces expression of uncoupling protein 1 (UCP1) of adipocytes via promoting irisin secretion from skeletal muscle. Male T2DM rats were treated with 0.4 mg/kg/d Lira twice a day for 8 weeks, and the protein expression of phosphorylated AMP kinase (p-AMPK), phosphorylated acetyl-CoA carboxylase 1 (p-ACC1) and UCP1 in white adipose tissues were detected. Differentiated C2C12 cells were treated with palmitic acid (PA) and Lira to detect the secretion of irisin. Differentiated 3T3-L1 cells were treated with irisin, supernatant from Lira-treated C2C12 cells, Compound C or siAMPKα1, the triglyceride (TG) content and the related gene expression were measured. The transcriptome in irisin-treated differentiated 3T3-L1 cells was analyzed. Lira elevated serum irisin levels, decreased the adipocyte size and increased the protein expression of UCP1, p-AMPK and p-ACC1 in WAT. Moreover, it promoted the expression of PGC1α and FNDC5, the secretion of irisin in PA-treated differentiated C2C12 cells. The irisin and supernatant decreased TG synthesis and promoted the expression of browning- and lipolysis-related genes in differentiated 3T3-L1 cells. While Compound C and siAMPKα1 blocked AMPK activities and expression, irisin partly reversed the pathway. Finally, the transcriptome analysis indicated that differently expressed genes are mainly involved in browning and lipid metabolism. Overall, our findings showed that Lira modulated muscle-to-adipose signaling pathways in diabetes via irisin-mediated AMPKα/ACC1/UCP1/PPARα pathway. Our results suggest a new mechanism for the treatment of T2DM by Lira.

Liraglutide 3.0 mg in the treatment of adults with obesity and prediabetes using real-world UK data: A clinical evaluation of a multi-ethnic population.

UK guidelines recommend liraglutide 3.0 mg in adults treated within specialist weight management services with BMI ≥35 kg/m2, prediabetes and high cardiovascular disease risk. We aimed to clinically evaluate liraglutide 3.0 mg in specialist weight management services. We evaluated liraglutide 3.0 mg in weight management services at Guys and St Thomas' NHS Foundation Trust. Objective body weight (BW) was measured at baseline and 4 months, allowing classification as 'responders' (≥5% BW reduction) and 'non-responders' (<5% BW reduction). One hundred and twenty-one patients were evaluated. At 4 months, 76.0% attended follow-up (82.6% responders, 17.4% non-responders); BW (-8.6 kg, 95%CI:-9.8, -7.4 kg), BMI (-3.2 kg/m2, 95%CI: -3.6, -2.8) and %-BW (-6.6%, IQR: -8.8%, -5.2%) significantly reduced. In responders, HbA1c reduced by -5.0 mmol/mol (IQR: -7.0. -4.0 mmol/mol). In responders BW continued to reduce up to 12 months (4 m: -10.2 kg, p < .0001; 6 m: -15.6 kg, p < .0001; 9 m: -16.5 kg, p < .0001; 12 m: -16.7 kg, p < .01). Those of Black African and Caribbean ethnicity experienced less BW loss than those of white ethnicity (4.12 kg, p = .017) and had a greater attrition rate. In adults with obesity and prediabetes who are treated within specialist weight management services, liraglutide 3.0 mg reduces BW and HbA1c. Those of Black African and Caribbean ethnicity experienced less BW reduction and greater attrition at 4 months. Further evaluation of the ethnic differences in response to obesity pharmacotherapy is required.

The GLP-1R as a model for understanding and exploiting biased agonism in next-generation medicines.

The glucagon-like peptide 1 receptor (GLP-1R) is a class B G protein-coupled receptor (GPCR) that emerged as a pharmacologic target in cardiometabolic disease, including diabetes and obesity, over 30 years ago. The subsequent widespread clinical use of GLP-1R agonists, including exenatide, liraglutide, and semaglutide, has made the GLP-1R a preeminent model for understanding basic GPCR biology, including the emergent field of biased agonism. Recent data demonstrate that the dual GLP-1R/glucose dependent insulinotropic polypeptide receptor (GIPR) agonist tirzepatide exhibits a biased signaling profile characterized by preferential Gαs activation over ß-arrestin recruitment, which appears to contribute to its insulinotropic and body-weight reducing effects in preclinical models. This constitutes a major finding in which nuanced, mechanistic receptor signaling dynamics in vitro mediate real-world clinical differentiation within a drug class. Because of the striking bench-top-to-bed side relevance of this biased signaling phenomenon, we have undertaken a review of the emerging data detailing biased agonism at the GLP-1R. In this review, we introduce the core concept of biased agonism followed by a detailed consideration of the key mechanisms, including ligand-mediated bias, receptor-mediated bias, and systems/cell-type bias. Current industry programs are largely, if not entirely, focused on developing biased ligands, and so we have dedicated a section of the review to a brief meta-analysis of compounds reported to drive biased signaling, with a consideration of the structural determinants of receptor-ligand interactions. In this work, we aim to assess the current knowledge regarding signaling bias at the GLP-1R and how these ideas might be leveraged in future optimization.

Exploring the association between suicidal thoughts, self-injury, and GLP-1 receptor agonists in weight loss treatments: Insights from pharmacovigilance measures and unmasking analysis.

INTRODUCTION: The study addresses concerns about potential psychiatric side effects of Glucagon-like peptide-1 receptor agonists (GLP-1 RA). AIM: The aim of this work was to analyse adverse drug reports (ADRs) from the Food and Drug Administration Adverse Events Reporting System (FAERS) using metformin and orlistat as comparators. METHODS: Descriptive and pharmacovigilance disproportionality analyses was performed. RESULTS: A total of 209,354 ADRs were reported, including 59,300 serious cases. Of those, a total of 5378 psychiatric disorder cases, including 383 'serious' cases related to selected ADRs were registered during 2005-2023. After unmasking, 271 cases where individual GLP-1 RA were implicated showing liraglutide (n = 90; Reported Odds Ratio (ROR) = 1.64), exenatide (n = 67; ROR = 0.80), semaglutide (n = 61; ROR = 2.03), dulaglutide (n = 45; ROR = 0.84), tirzepatide (n = 5; ROR = 1.76) and albiglutide (n = 2; ROR = 0.04). A greater association between these ADRs with metformin was observed, but not orlistat. With regards to selected preferred terms (PTs), 42 deaths including 13 completed suicides were recorded. Suicidal ideation was recorded in n = 236 cases for 6/7 GLP-1 RA (excluding lixisenatide). DISCUSSION: Suicide/self-injury reports pertaining to semaglutide; tirzepatide; and liraglutide were characterised, although lower than metformin. It is postulated that rapid weight loss achieved with GLP-1 RA can trigger significant emotional, biological, and psychological responses, hence possibly impacting on suicidal and self-injurious ideations. CONCLUSIONS: With the current pharmacovigilance approach, no causality link between suicidal ideation and use of any GLP-1 RA can be inferred. There is a need for further research and vigilance in GLP-1 RA prescribing, particularly in patients with co-existing psychiatric disorders.

[Current State of Pharmacotherapy in Obesity].

The prevalence of obesity with various complications is increasing rapidly in Korea. Although lifestyle modification is fundamental in obesity treatment, more effective treatment tools are required. Many advances in obesity treatment have been reported recently, including lifestyle modifications and pharmacological, endoscopic, and surgical treatments. Drugs with proven long-term efficacy and safety are preferred because management for obesity treatment is a long-term process. Currently, four medications are available for long-term use in Korea: Orlistat, Naltrexone/bupuropion NR, Phentermine/topiramate capsule, and Liraglutide. Recently, semaglutide and tirzepatide have been attracting attention because of their effectiveness and convenience, but they are not yet available in Korea. In addition, there are limitations such as the yo-yo effect when discontinuing the drug, long-term safety, and cost. Patients and medical staff must be aware of the advantages and side effects of each medication to ensure the successful treatment of obesity.

Comparison of the Efficacy of Anti-Obesity Medications in Real-World Practice.

Purpose: Anti-obesity medications (AOMs), along with lifestyle interventions, are effective means of inducing and maintaining weight loss in patients with obesity. Although the efficacy of AOMs has been reported, there have been no direct comparisons of these drugs. Therefore, in the present study, we aimed to compare the efficacy of all the AOMs available in Korea in a real-world setting. Patients and Methods: The body weight and composition of 205 adults treated with phentermine, phentermine/topiramate, liraglutide, naltrexone/bupropion, lorcaserin, or orlistat for at least 6 months were analyzed at 2 month intervals. The prevalence of the achievement of a ≥5% weight loss and the changes in body composition were compared between participants using each AOM at each visit. Results: A total of 132 (64.4%) participants achieved ≥5% weight loss within 6 months (prevalence of ≥5% weight loss after 6 months: phentermine, 87.2%; phentermine/topiramate, 67.7%; liraglutide, 58.1%; naltrexone/bupropion, 35.3%; lorcaserin, 75%; orlistat, 50%). At each visit, after adjustment for age, sex, and baseline body weight, phentermine use was associated with a significantly higher prevalence of ≥5% weight loss than the use of the other AOMs, except for liraglutide. There were significant differences in the body weight, body mass index and body fat mass among the AOM groups by visit (P for interaction <0.05), but not in their waist circumference, skeletal muscle mass, percentage body fat, or visceral fat area. Conclusion: All the AOMs were effective at inducing and maintaining weight loss, in the absence of significant changes in muscle mass, over a 6 month period, and the short-term use of phentermine and the long-term use of phentermine/topiramate or liraglutide would be practical choices for the treatment of obesity. However, further, large-scale studies are necessary to confirm these findings.

Liraglutide improved the reproductive function of obese mice by upregulating the testicular AC3/cAMP/PKA pathway.

BACKGROUND: The incidence of male reproductive dysfunction is increasing annually, and many studies have shown that obesity can cause severe harm to male reproductive function. The mechanism of male reproductive dysfunction caused by obesity is unclear, and there is no ideal treatment. Identification of effective therapeutic drugs and elucidation of the molecular mechanism involved in male reproductive health are meaningful. In this study, we investigated the effects of the GLP-1 receptor agonist liraglutide on sex hormones, semen quality, and testicular AC3/cAMP/PKA levels in high-fat-diet-induced obese mice. METHODS: Obese mice and their lean littermates were treated with liraglutide or saline for 12 weeks. Body weight was measured weekly. Fasting blood glucose (FBG) was measured using a blood glucose test strip. The serum levels of insulin (INS), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), free testosterone (F-TESTO), estradiol (E2), and sex hormone binding globulin (SHBG) were detected using ELISA. The sperm morphology and sperm count were observed after Pap staining. The mRNA and protein expression levels of testicular GLP-1R and AC3 were measured by RT-qPCR and Western blot, respectively. Testicular cAMP levels and PKA activity were detected using ELISA. RESULTS: Liraglutide treatment can decrease body weight, FBG, INS, HOMA-IR, E2 and SHBG levels; increase LH, FSH, T, and F-TESTO levels; increase sperm count; decrease the sperm abnormality rate; and increase GLP-1R and AC3 expression levels and cAMP levels and PKA activity in testicular tissue. CONCLUSIONS: Liraglutide can improve the sex hormone levels and semen quality of obese male mice. In addition to its weight loss effect, liraglutide can improve the reproductive function of obese male mice, which may also be related to the upregulation of AC3/cAMP/PKA pathway in the testis. This work lays the groundwork for future clinical studies.

A Review and Meta-Analysis of the Safety and Efficacy of Using Glucagon-like Peptide-1 Receptor Agonists.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been used to reduce glucose levels in patients with type 2 diabetes mellitus since 2005. This meta-analysis discusses the mechanisms and potential benefits of several GLP-1 RAs. In particular, this meta-analysis focuses on the safety and associations with weight loss, glucose reduction, cardiovascular outcomes, heart failure, and renal outcomes of GLP-1 RAs to determine their benefits for patients with different conditions. In terms of glycemic control and weight loss, semaglutide was statistically superior to other GLP-1 RAs. In terms of cardiovascular outcomes, 14 mg of semaglutide taken orally once daily and 1.8 mg of liraglutide injected once daily reduced the incidence of cardiovascular death, whereas other GLP-1 RAs did not provide similar benefits. Moreover, semaglutide was associated with superior outcomes for heart failure and cardiovascular death in non-diabetic obesity patients, whereas liraglutide worsened heart failure outcomes in diabetic patients with a reduced ejection fraction. Additionally, semaglutide, dulaglutide, and liraglutide were beneficial in terms of composite renal outcomes: These GLP-1 RAs were significantly associated with less new or persistent macroalbuminuria, but not with improved eGFR deterioration or reduced requirement for renal replacement therapy. However, GLP-1 RAs may benefit patients with type 2 diabetes mellitus or obesity.

Protecting cardiomyocytes from hypoxia-reoxygenation injury, empaglifozin and liraglutide alone or in combination?

OBJECTIVES: Empagliflozin, a sodium-dependent glucose co-transporter 2 (SGLT2) inhibitor, and liraglutide, a GLP-1 receptor (GLP-1R) agonist, are commonly recognized for their cardiovascular benefits in individuals with type 2 diabetes (T2D). In prior studies, we have demonstrated that both drugs, alone or in combination, were able to protect cardiomyocytes from injury induced by diabetes. Mechanistic investigations also suggested that the cardioprotective effect may be independent of diabetes In this study, we utilized a hypoxia-reoxygenation (H/R) model to investigate the cardiovascular benefits of SGLT2 inhibitor empagliflozin and GLP-1 receptor (GLP-1R) agonist liraglutide, both alone and in combination, in the absence of T2D. Our hypothesis was that empagliflozin and liraglutide, either individually or in combination, would demonstrate cardioprotective properties against H/R-induced injury, with an additive and/or synergistic effect anticipated from combination therapy. METHODS: In this study, the cardiac muscle cell line, HL-1 cells, were treated with vehicle, empagliflozin, liraglutide, or a combination of the two drugs. The cells were then subjected to a hypoxia-reoxygenation (H/R) protocol, consisting of 1 h of hypoxia followed by 24 h of reoxygenation. The effects of the treatments on cytotoxicity, oxidative stress, endothelial nitric oxide synthase (eNOS) activity, phospho-protein kinase C (PKC) beta and phospho-eNOS (Thr495) expression were subsequently evaluated at the end of the treatments. RESULTS: We found that H/R increased cytotoxicity and reduces eNOS activity, empagliflozin, liraglutide or combination treatment attenuated some or all of these effects with the combination therapy showing the greatest improvement. CONCLUSIONS: Empagliflozin, liraglutide or combination of these two have cardioprotective effect regardless of diabetes. Cardioprotective effects of SGLT2 inhibitor and GLP-1R agonist is additive and synergistic.

Liraglutide attenuates angiotensin II-induced aortic dissection and aortic aneurysm via inhibiting M1 macrophage polarization in APOE -/- mice.

BACKGROUND: Aortic Aneurysm and Dissection (AAD) are severe cardiovascular conditions with potentially lethal consequences such as aortic rupture. Existing studies suggest that liraglutide, a long-acting glucagon-like peptide receptor (GLP-1R) agonist, offers protective benefits across various cardiovascular diseases. However, the efficacy of liraglutide in mitigating AAD development is yet to be definitively elucidated. METHODS: Ang II (Angiotension II) infusion of APOE-/- mouse model with intraperitoneal injection of liraglutide (200 µg/kg) to study the role of GLP-1R in AAD formation. Bone Marrow Derived Macrophages (BMDM) and Raw264.7 were incubated with LPS, liraglutide, exendin 9-39 or LY294002 alone or in combination. SMC phenotype switching was examined in a macrophage and vascular smooth muscle cell (VSMC) co-culture system. An array of analytical methods, including Western Blot, Immunofluorescence Staining, Enzyme-LinkedImmunosorbent Assay, Real-Time Quantitative Polymerase Chain Reaction, RNA-seq, and so on were employed. RESULTS: Our investigation revealed a significant increase in M1 macrophage polarization and GLP-1R expression in aortas of AD patients and Ang II-induced AAD APOE-/- mice. Administering liraglutide in APOE-/- mice notably reduced Ang II-induced AAD incidence and mortality. It was found that liraglutide inhibits M1 macrophage polarization primarily via GLP-1R activation, and subsequently modulates vascular smooth muscle cell phenotypic switching was the primary mechanism. RNA-Seq and subsequent KEGG enrichment analysis identified CXCL3, regulated by the PI3K/AKT signaling pathway, as a key element in liraglutide's modulation of M1 macrophage polarization. CONCLUSION: Our study found liraglutide exhibits protective effects against AAD by modulating M1 macrophage polarization, suppressing CXCL3 expression through the PI3K/AKT signaling pathway. This makes it a promising therapeutic target for AAD, offering a new avenue in AAD management.

Liraglutide prevents cellular senescence in human retinal endothelial cells (HRECs) mediated by SIRT1: an implication in diabetes retinopathy.

Diabetes mellitus (DM) is a chronic metabolic disorder affecting millions of people worldwide, characterized by dysregulated glucose homeostasis and hyperglycemia. Diabetic retinopathy (DR) is one of the serious multisystemic complications. Aging is an important risk factor for DR. Endothelial sirtuin 1 (SIRT1) plays an important role in regulating the pathophysiology of glucose metabolism, cellular senescence, and aging. Liraglutide, an analog of Glucagon-like peptide 1 (GLP-1), has been widely used in the treatment of DM. However, the effects of Liraglutide on DR are less reported. Here, we investigated whether treatment with Liraglutide has beneficial effects on high glucose (HG)-induced injury in human retinal microvascular endothelial cells (HRECs). First, we found that exposure to HG reduced the expression of glucagon-like peptide 1 receptor 1 (GLP-1R). Additionally, Liraglutide ameliorated HG-induced increase in the expression of vascular endothelial growth factor-A (VEGF-A) and interleukin 6 (IL-6). Importantly, Liraglutide ameliorated cellular senescence and increased telomerase activity in HG-challenged HRECs. Liraglutide also reduced the levels of p53 and p21. Mechanistically, Liraglutide restored the expression of SIRT1 against HG. In contrast, the knockdown of SIRT1 abolished the protective effects of Liraglutide in cellular senescence of HRECs. Our findings suggest that Liraglutide might possess a benefit on DR mediated by SIRT1.

Comparing the effects of empagliflozin and liraglutide on lipid metabolism and intestinal microflora in diabetic mice.

Background and Objectives: Recent studies have shown that the imbalance of intestinal flora is related to the occurrence and progression of diabetic nephropathy (DN) and can affect lipid metabolism. Sodium-dependent glucose transporters 2 (SGLT2) inhibitor and glucagon-like peptide-1 (GLP-1) receptor agonist are commonly used hypoglycemic drugs and have excellent renal safety. The purpose of this study was to compare the protective effects of empagliflozin and liraglutide on kidneys, lipid metabolism, and intestinal microbiota in diabetic mice. Methods: We established a mouse model of type two diabetes by feeding rats a high-fat diet (HFD) followed by an intraperitoneal injection of STZ. The mice were randomly divided into groups: normal control (NC), diabetic model (DM), liraglutide treatment (LirT), empagliflozin treatment (EmpT), and liraglutide combined with empagliflozin treatment (Emp&LirT) groups. Blood glucose, lipids, creatinine, and uric acid, as well as urinary nitrogen and albumin levels were measured. The renal tissues were subjected to HE, PAS and Masson's staining. These parameters were used to evaluate renal function and histopathological changes in mice. Mice feces were also collected for 16sRNA sequencing to analyze the composition of the intestinal flora. Results: All the indexes related to renal function were significantly improved after treatment with drugs. With respect to lipid metabolism, both drugs significantly decreased the serum triglyceride levels in diabetic mice, but the effect of liraglutide on reducing serum cholesterol was better than that of empagliflozin. However, empagliflozin had a better effect on the reduction of low-density lipoproteins (LDL). The two drugs had different effects on intestinal flora. At the phylum level, empagliflozin significantly reduced the ratio of Firmicutes to Bacteroidota, but no effect was seen with liraglutide. At the genus level, both of them decreased the number of Helicobacter and increased the number of Lactobacillus. Empagliflozin also significantly increased the abundance of Muribaculaceae, Muribaculum, Olsenella, and Odoribacter, while liraglutide significantly increased that of Ruminococcus. Conclusion: Liraglutide and empagliflozin were both able to improve diabetes-related renal injury. However, the ability of empagliflozin to reduce LDL was better compared to liraglutide. In addition, their effects on the intestine bacterial flora were significantly different.