Liraglutide Research Articles

Therapeutic Potential of Liraglutide for Diabetes-Periodontitis Comorbidity: Killing Two Birds with One Stone.

Background The relationship between diabetes and periodontitis is bidirectional, and there is now consensus that periodontitis and diabetes are comorbid. There is a quest for a drug that can be used to treat both conditions simultaneously. This study evaluated the anti-inflammatory and osteoprotective effects of liraglutide (LIRA) on periodontitis in diabetic rats. Methods Male Wistar rats (n = 46) were randomly divided into four groups: control group (n = 8), LIRA group (n = 8), diabetes-associated periodontitis+0.9% saline group (diabetic periodontitis (DP)+NaCl group, n = 15), and diabetes-associated periodontitis+LIRA group (DP+LIRA group, n = 15). LIRA treatment lasted for 4 weeks (300 μg/kg/d) after establishment of a rat model of DP. The expression of IL-6, TNF-α, and IL-1β was detected by enzyme-linked immunosorbent assay. The morphological changes of periodontal tissues were observed by hematoxylin–eosin staining. The absorption of alveolar bone and its ultrastructural changes were observed by histomorphometry and microcomputed tomography. The expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in alveolar bone was detected by immunohistochemistry. The levels of Runx2 mRNA and ALP mRNA in the gingival epithelium were examined by quantitative real-time polymerase chain reaction. Results LIRA decreased alveolar bone resorption, improved the microstructure of alveolar bone, and reduced periodontal inflammation and damage (P < 0.05). LIRA also reduced blood glucose level and inhibited the secretion of serum IL-6, TNF-α, and IL-1β (P < 0.05). In addition, after treatment with LIRA, the ratio of RANKL/OPG was reduced, and the expression levels of ALP mRNA and Runx2 mRNA were upregulated (P < 0.05). Conclusions LIRA not only controls blood glucose level but also reduces inflammation and bone loss and enhances osteogenic differentiation in diabetes-associated periodontitis. Those indicate that LIRA may be used as a potential medicine for the adjunctive therapy of diabetes-periodontitis comorbidity.

Synergistic effect of glucagon-like peptide-1 analogue liraglutide and ZnO on the antibacterial, hemostatic, and wound healing properties of nanofibrous dressings

Bacterial infections and poor vascularization delay wound healing, thus necessitating alternative strategies for functional wound dressings. Zinc oxide (ZnO) has been shown to exert a potent antibacterial effect against bacterial species. Similarly, Glucagon-like peptide-1 (GLP-1) analogue liraglutide (LG) has been shown to promote vascularization and improve wound healing. The objective of this research was to investigate the synergistic effect of ZnO nanoparticles (ZnO-NPs) and LG to simultaneously induce antibacterial, hemostatic, and vascularization effects for infected wound healing. Electrospun poly (l-lactide-co-glycolide)/gelatin (PLGA/Gel) membranes containing ZnO-NPs and LG displayed good biocompatibility and hemostatic ability. Both, ZnO-NPs and LG exhibited synergistic antibacterial effect against Staphylococcus aureus and Escherichia coli as well as improved the migration and tubule-like network formation of human umbilical vein endothelial cells (HUVECs) invitro. Once evaluated in a bacterial-infected wound model in rats, the membranes loaded with ZnO-NPs and LG effectively promoted wound healing causing significant reduction in wound area and scar-like tissue formation. Therefore, ZnO-NPs/LG synergism may offer an invaluable solution for the treatment of poorly healing infected wounds.

Liraglutide chronic treatment prevents development of tolerance to antiseizure effects of diazepam in genetically epilepsy prone rats

Glucagon-like peptide-1 (GLP-1) is a hormone that can regulate several neuronal functions. The modulation of GLP-1 receptors emerged as a potential target to treat several neurological diseases, such as epilepsy. Here, we studied the effects of acute and chronic treatment with liraglutide (LIRA), in genetically epilepsy prone rats (GEPR-9s). We have also investigated the possible development of tolerance to antiseizure effects of diazepam, and how LIRA could affect this phenomenon over the same period of treatment. The present data indicate that an acute treatment with LIRA did not diminish the severity score of audiogenic seizures (AGS) in GEPR-9s. By contrast, a chronic treatment with LIRA has shown only a modest antiseizure effect that was maintained until the end of treatment, in GEPR-9s. Not surprisingly, acute administration of diazepam reduced, in a dose dependent manner, the severity of the AGS in GEPR-9s. However, when diazepam was chronically administered, an evident development of tolerance to its antiseizure effects was detected. Interestingly, following an add-on treatment with LIRA, a reduced development of tolerance and an enhanced diazepam antiseizure effect was observed in GEPR-9s. Overall, an add-on therapy with LIRA demonstrate benefits superior to single antiseizure medications and could be utilized to treat epilepsy as well as associated issues. Therefore, the potential use of GLP1 analogs for the treatment of epilepsy in combination with existing antiseizure medications could thus add a new and long-awaited dimension to its management.

366-OR: 14-3-3-ζ Contributes to Effect of ß-Cell GLP1 Receptor Signaling to Alter a-Cell Proglucagon Processing

Glucagon like peptide 1 (GLP1) , a classically gut derived hormone, potentiates insulin secretion. New evidence suggests that α cells can produce GLP1 under certain conditions, which may offer a novel therapeutic modality for treating diabetes; however, the mechanisms regulating α cell GLP1 production are unknown. We previously found that enhanced β cell GLP1 receptor (GLP1R) signaling activates α cell GLP1 by activating prohormone convertase 1/3 (Pcsk1) expression. We tested the hypothesis that enhanced β cell GLP1R signaling activates α cell GLP1 production through paracrine factors. We studied the impact of conditioned media (CM) generated from β cell GLP1R WT and KO islets of saline (CTRL) and liraglutide (LIRA) treated mice on α cell gene expression and function. CM from LIRA treated islets increased α cell Pcsk1 expression and active GLP-1 secretion only if β cells expressed the GLP1R (Pcsk1 expression (AU) : CTRL WT=1.0±0.1, LIRA WT=2.0±0.3, CTRL KO=1.1±0.2, LIRA KO=1.1±0.2, P&amp;lt;0.01; active GLP-1 (pg/mL) : CTRL WT=124±44, LIRA WT=682±247, CTRL KO=173±101, LIRA KO=116±30, P&amp;lt;0.05) . Subsequent identification of the proteome secreted by mouse and human islets in response to LIRA and CTRL revealed 14-3-3-ζ as a lead candidate in the regulation of α cell Pcsk1 expression. To assess the role of 14-3-3-ζ, islets from LIRA treated mice were treated with and without 14-3-3-ζ, and islets from CTRL treated mice were treated with and without the 14-3-3 inhibitor, R18. Addition of 14-3-3-ζ ablated the effect of CM from LIRA treated islets to increase α cell Pcsk1 expression, while inhibition of 14-3-3 with R18 in CTRL islets resulted in CM that mimicked the effect of CM from LIRA treated islets to stimulate α cell Pcsk1 expression (Pcsk1 expression: CTRL=1.1±0.2, R18=2.0±0.2, LIRA=2.4±0.3, LIRA+14-3-3-ζ=1.3±0.1, P&amp;lt;0.05) . These data refine our understanding of α cell GLP1 regulation and identify 14-3-3-ζ as a potential target with which to enhance α cell GLP1 production for diabetes treatment. Disclosure M.Holter: None. B.Cummings: None. D.Phuong: None. I.S.H.Lee: None. M.Saikia: None. L.A.Weikert: Stock/Shareholder; Merck &amp; Co., Inc., Oramed Pharmaceuticals. E.T.Anderson: None. Q.Fu: None. S.Zhang: None. K.Sloop: Employee; Eli Lilly and Company. Funding NIH/NIDDK (F30 DK126538) Department of Defense (W81XWH-18-1-0206) The Hartwell Foundation NIH/NIDDK (R56DK124853)

738-P: The Real-World Observational Prospective Study of Health Outcomes with Dulaglutide and Liraglutide in Type 2 Diabetes Patients (TROPHIES) : Final 24-Month Patient-Reported Outcomes

Data on patient-reported outcome (PRO) measures in people living with T2D who initiate injectable glucagon-like peptide-1 receptor agonist (GLP-1 RA) medication in routine clinical practice are limited. Here we present final PRO data from the TROPHIES 24-month, prospective, non-comparative, observational study of adult patients with T2D in France, Germany and Italy who started their first injectable GLP-1 RA with either once-weekly dulaglutide (DU) or once-daily liraglutide (LIRA) . Patients’ scores on PRO questionnaires were assessed every 6 months. We present scores at 24 months compared with baseline values before starting DU or LIRA treatment. For each PRO measure, higher scores reflect better outcomes. Baseline characteristics (previously published) for patients prescribed DU (N=1,014) or LIRA (N=991) were similar between groups. Mean changes from baseline to 24 months in PRO scores indicate improvements in health outcomes in patients initiating DU or LIRA (Table) . In summary, among those patients still evaluable at 24 months we observed improvements in PRO scores from baseline in both groups, but with a more pronounced trend of improvement in the DU cohort for EQ-5D-5L VAS, IW-SP, DTSQs total, and DPM life and work productivity scores. Disclosure M.Fuechtenbusch: Advisory Panel; Berlin-Chemie AG, Consultant; Boehringer Ingelheim International GmbH, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Speaker's Bureau; AstraZeneca, Novo Nordisk. K.Boye: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. B.Guerci: Advisory Panel; Amgen Inc., Medtronic, Board Member; Abbott Diagnostics, AstraZeneca, Bayer AG, Eli Lilly and Company, Novartis Pharmaceuticals Corporation, Consultant; Boehringer Ingelheim International GmbH, Intercept Pharmaceuticals, Inc., Novo Nordisk. F.Giorgino: Advisory Panel; AstraZeneca, Boehringer Ingelheim International GmbH, Novo Nordisk, Consultant; Lilly Diabetes, Sanofi, Research Support; Lilly Diabetes, Roche Diabetes Care, Takeda Pharmaceutical Company Limited. L.Garcia-perez: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. E.Heitmann: None. J.Lebrec: Consultant; Eli Lilly and Company. A.Barrett: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. A.Dib: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. M.Orsini federici: Employee; Eli Lilly and Company.

MO617: Liraglutide Improves Both Diabetic Nephropathy and Cardiomyopathy in the SDT Fatty Rat, A Cardiorenal Model of Type 2 Diabetes

Abstract BACKGROUND AND AIMS The Glucagon-like peptide 1 (GLP-1) receptor agonist liraglutide (LIRA) has cardioprotective effects and may reduce the development of kidney disease in type 2 diabetic patients. We here evaluated the effects of LIRA on both kidney and heart function in the Spontaneously Diabetic Torii (SDT) fatty rat, a type 2 diabetic cardiorenal model. METHOD SDT fatty male rats were treated subcutaneously with vehicle or LIRA 0.4 mg/kg QD for 10 weeks. To measure the effects of LIRA on glomerular hyperfiltration, rats were injected with FITC-sinistrin to measure glomerular filtration rate (GFR) at 4 weeks of treatment. At 5 weeks of treatment, rats underwent unilateral nephrectomy and were put on a 0.3% salt diet to induce a GFR decline. GFR was then measured at 10 weeks of treatment, before hemodynamics measurement and echocardiography. RESULTS Compared with vehicle, LIRA induced significant body weight loss, as well as blood glucose levels reduction by up to ∼20%. During the hyperfiltration phase, LIRA attenuated hyperfiltration, with a 19% lower GFR versus vehicle (P &amp;lt; 0.05). In vehicle-treated animals, unilateral nephrectomy and 0.3% salt diet induced a major reduction (−56%) in GFR, as expected. After 10 weeks of treatment, LIRA markedly attenuated this GFR decline (vehicle: 9.3 ± 0.5 mL/min/kg; LIRA: 13.3 ± 0.9 mL/min/kg, P &amp;lt; 0.001 versus vehicle). Compared with vehicle, LIRA also lowered urine albumin-to-creatinine ratio both in the hyperfiltration and GFR decline phases, and significantly reduced kidney inflammation and fibrosis histology scores. LIRA showed significant reduction in cardiac hypertrophy, as well as both arterial and left ventricle end-systolic pressures. Moreover, LIRA normalized the diastolic dysfunction with preserved ejection fraction observed in SDT fatty rats (P &amp;lt; 0.001 versus vehicle). CONCLUSION In the SDT fatty rat, LIRA shows significant benefits by reducing renal hyperfiltration, preventing GFR decline, and improving cardiac hypertrophy, blood pressure and diastolic dysfunction. This preclinical model will be useful to evaluate drugs targeting the cardiorenal axis in type 2 diabetes.

Liraglutide Is Protective against Brain Injury in Mice with Febrile Seizures by Inhibiting Inflammatory Factors.

The febrile seizure (FS) is a common disease in emergency pediatrics, and about 30% of patients are children aged between 6 months and 5 years. Therefore, we aim to observe the protective impact of liraglutide (LIR) on brain injury in mice with FS and to explore its relevant mechanisms. Male SD mice were selected, and the FS model was established by heat bath method. The behavioral score was performed on mice with Racine grading, and nerve cells in apoptosis in the hippocampus were determined by TUNEL. The content of glutamate was determined by ELISA. mRNA levels and protein expression of GLP-1, GLP-1R, IL-1β, IL-6, TNF-α, and cleaved-caspase 3 were examined in mice by q-PCR and WB. Protein expression of γ-aminobutyric acid was influenced by WB as well. LIR prolonged the seizure latency and seizure duration in mice with FS. The GLP-1 and GLP-1R in the mouse hippocampus with FS expressed highly and also inhibited the number of nerve cells in apoptosis, decreased glutamate content, and increased γ-aminobutyric acid expression in the mouse hippocampus with FS. In addition, The IL-1β, IL-6, and TNF-α, in the mouse hippocampus with FS expressed to reduce with LIR. LIR is protective against brain injury in mice with FS and protects brain injury by inhibiting inflammatory factors in mice with FS. Our finding provides a reference for mitigating and delaying the development of FS as well as the prevention and treatment of brain injury caused by FS.

Liraglutide Alleviates Diabetic Atherosclerosis through Regulating Calcification of Vascular Smooth Muscle Cells.

Background Diabetes mellitus (DM) is a group of metabolic diseases characterized by hyperglycemia, which can induce the development of atherosclerosis (AS). Calcification of vascular smooth muscle cells (VSMCs) exerts an important role in the process of AS. In this study, the effects of liraglutide (LIRA) on VSMC under high-glucose condition and its mechanism were explored. Method After VSMC was treated by high glucose with or without LIRA in vitro, the alkaline phosphatase (ALP) activity was measured by the detection kit, osteogenic marker protein expression was detected by Western blotting, and calcification was determined by alizarin red staining. Subsequently, the DM rat model was established and the ALP activity, calcification, and osteogenic marker proteins were determined in vivo. Immunohistochemical (IHC) staining and hematoxylin-eosin staining were performed on the thoracic aorta of DM rats. Result The positive rate of SMα-actin expression in the DM + AS group was significantly lower than that in control rats, but LIRA administration increased the positive rate in the model. The expression of Cbfα-1 and OPN in the DM + AS group was significantly higher than that in the control group, while it was decreased after treatment of LIRA. The ALP activity and calcium content were increased in DM + AS rats, and the treatment of LIRA decreased the phenotypes in the rats, so as to delay the progression of AS in DM rats. Meanwhile, LIRA inhibited the ALP activity, upregulated SM-α expression, and downregulated expression of OPN and Cbfα-1 in VSMC under high-glucose (HG) conditions. Mechanically, HG-enhanced ALP activity, AKT, and ERK phosphorylation were inhibited by LIRA, PI3K antagonist LY294002, or ERK1/2 antagonist PD98059, in which cotreatment of LIRA with LY294002 and PD98059 could further enhance the effect of LIRA on VSMC, and GLP-1R antagonists reversed the phenotypes in the model. LIRA blocked the osteogenic transformation of VSMC through PI3K and ERK1/2 signaling pathways, which can be reversed by GLP-1R antagonists. Conclusion LIRA inhibited the abnormalities in VSMC calcification mediated by the GLP-1R, which was related to PI3K/Akt and ERK1/2 MAPK pathways. Therefore, the prospect and significance of LIRA in the treatment of DM complicated with AS were clarified.

Anti-inflammatory potential of liraglutide, a glucagon-like peptide-1 receptor agonist, in rats with peripheral acute inflammation.

The present study aimed to explore the possible anti-inflammatory actions of liraglutide (LRG), a glucagon-like peptide-1 (GLP-1) receptor agonist, and to compare with tramadol (TR) or LRG, and TR combination treatment by investigating the inflammatory signs such as pain hypersensitivity, edema, and fever in carrageenan (CG)-induced acute peripheral inflammation model in rats. The levels of several biomarkers for inflammatory status, angiogenesis, and oxidative stress were also measured in inflamed tissues. CG induced inflammation in the paws of rats identified by hypersensitivities, redness, edema and fever. LRG, significantly improved the hypersensitivity to mechanical (from 4 to 35.5g) or cold (from 5 to 44.2s) stimuli, reduced the edema (paw mass, from 2.54 to 1.85g), and fever (paw temperature, from 33.6 to 27.3°C). LRG dramatically suppressed the inflammatory signs when compared to those of TR. In addition, co-administration of TR and LRG resulted in further reduction of sensitivity to mechanical and cold stimuli. Anti-inflammatory potential of LRG altered depending on their inhibitory effects in the biomarkers of inflamed paws. Consequently, the suppressive actions of LRG in the inflammation induced hypersensitivities, edema, and fever, indicating that these drugs have significant anti-inflammatory potential with anti-hypersensitivities, anti-edema, and anti-pyretic effects. LRG with anti-inflammatory actions may be a highly promising therapeutic option for the management of inflammatory conditions or inflammatory-related various diseases.

Liraglutide preserves CD34+ stem cells from dysfunction Induced by high glucose exposure

BackgroundGlucagon like peptide-1 receptor agonists (GLP-1RAs) have shown to reduce mortality and cardiovascular events in patients with type 2 diabetes mellitus (T2DM). Since the impairment in number and function of vasculotrophic circulating CD34+ hematopoietic stem progenitor cells (HSPCs) in T2D has been reported to increase cardiovascular (CV) risk, we hypothesized that one of the mechanisms whereby GLP-1 RAs exert CV protective effects may be related to the ability to improve CD34+ HSPC function.MethodsIn cord blood (CB)-derived CD34+ HSPC, the expression of GLP-1 receptor (GLP-1R) mRNA, receptor protein and intracellular signaling was evaluated by RT-qPCR and Western Blot respectively. CD34+ HSPCs were exposed to high glucose (HG) condition and GLP-1RA liraglutide (LIRA) was added before as well as after functional impairment. Proliferation, CXCR4/SDF-1α axis activity and intracellular ROS production of CD34+ HSPC were evaluated.ResultsCD34+ HSPCs express GLP-1R at transcriptional and protein level. LIRA treatment prevented and rescued HSPC proliferation, CXCR4/SDF-1α axis activity and metabolic imbalance from HG-induced impairment. LIRA stimulation promoted intracellular cAMP accumulation as well as ERK1/2 and AKT signaling activation. The selective GLP-1R antagonist exendin (9–39) abrogated LIRA-dependent ERK1/2 and AKT phosphorylation along with the related protective effects.ConclusionWe provided the first evidence that CD34+ HSPC express GLP-1R and that LIRA can favorably impact on cell dysfunction due to HG exposure. These findings open new perspectives on the favorable CV effects of GLP-1 RAs in T2DM patients.

Regulation of neuroinflammation with GLP-1 receptor targeting nanostructures to alleviate Alzheimer’s symptoms in the disease models

The neuroinflammation induced by amyloid-β (Aβ) has emerged as an important role in onset and progression of Alzheimer’s disease (AD). Hence, regulating the inflammatory mediators produced by glial cells is valuable for AD treatment. Here we developed a glucagon-like peptide 1 receptor (GLP-1R) agonist with blood-brain barrier (BBB) crossing capability to suppress inflammation induced by microglia and astrocyte. Liraglutide (LRGT) was decorated with angiopep-2 peptide and assembled with polyethylene glycol (PEG) to form a nanostructure (pALRGT), showing a higher brain accumulation than free LRGT. Treatment with pALRGT nanostructures could inhibit the secretion of pro-inflammatory cytokines from the activated microglia through PI3K-AKT/NF-κB pathways. Meanwhile, pALRGT nanostructures promoted the differentiation of astrocytes into protective A2 type and secreted IL-3 for Aβ peptide clearance. Consequently, pALRGT nanostructures significantly alleviated the progression of Aβ peptide induced AD in mice. This study demonstrates a novel strategy to modulate microglia activation and astrocyte reactivity for alleviating the progression of AD.

Liraglutide Reduces Vascular Damage, Neuronal Loss, and Cognitive Impairment in a Mixed Murine Model of Alzheimer's Disease and Type 2 Diabetes.

Alzheimer’s disease is the most common form of dementia, and epidemiological studies support that type 2 diabetes (T2D) is a major contributor. The relationship between both diseases and the fact that Alzheimer’s disease (AD) does not have a successful treatment support the study on antidiabetic drugs limiting or slowing down brain complications in AD. Among these, liraglutide (LRGT), a glucagon-like peptide-1 agonist, is currently being tested in patients with AD in the Evaluating Liraglutide in Alzheimer’s Disease (ELAD) clinical trial. However, the effects of LRGT on brain pathology when AD and T2D coexist have not been assessed. We have administered LRGT (500 μg/kg/day) to a mixed murine model of AD and T2D (APP/PS1xdb/db mice) for 20 weeks. We have evaluated metabolic parameters as well as the effects of LRGT on learning and memory. Postmortem analysis included assessment of brain amyloid-β and tau pathologies, microglia activation, spontaneous bleeding and neuronal loss, as well as insulin and insulin-like growth factor 1 receptors. LRGT treatment reduced glucose levels in diabetic mice (db/db and APP/PS1xdb/db) after 4 weeks of treatment. LRGT also helped to maintain insulin levels after 8 weeks of treatment. While we did not detect any effects on cortical insulin or insulin-like growth factor 1 receptor m-RNA levels, LRGT significantly reduced brain atrophy in the db/db and APP/PS1xdb/db mice. LRGT treatment also rescued neuron density in the APP/PS1xdb/db mice in the proximity (p = 0.008) far from amyloid plaques (p < 0.001). LRGT reduced amyloid plaque burden in the APP/PS1 animals (p < 0.001), as well as Aβ aggregates levels (p = 0.046), and tau hyperphosphorylation (p = 0.009) in the APP/PS1xdb/db mice. Spontaneous bleeding was also ameliorated in the APP/PS1xdb/db animals (p = 0.012), and microglia burden was reduced in the proximity of amyloid plaques in the APP/PS1 and APP/PS1xdb/db mice (p < 0.001), while microglia was reduced in areas far from amyloid plaques in the db/db and APP/PS1xdb/db mice (p < 0.001). This overall improvement helped to rescue cognitive impairment in AD-T2D mice in the new object discrimination test (p < 0.001) and Morris water maze (p < 0.001). Altogether, our data support the role of LRGT in reduction of associated brain complications when T2D and AD occur simultaneously, as regularly observed in the clinical arena.

Glucagon-like peptide-1 receptor agonist, liraglutide, reduces heroin self-administration and drug-induced reinstatement of heroin-seeking behaviour in rats.

Drug addiction is a chronic brain disease characterized by the uncontrolled use of a substance. Due to its relapsing nature, addiction is difficult to treat, as individuals can relapse following even long periods of abstinence and, it is during this time, that they are most vulnerable to overdose. In America, opioid overdose has been increasing for decades, making finding new treatments to help patients remain abstinent and prevent overdose deaths imperative. Recently, glucagon-like peptide-1 (GLP-1) receptor agonists have shown promise in reducing motivated behaviours for drugs of abuse. In this study, we test the effectiveness of the GLP-1 analogue, liraglutide (LIR), in reducing heroin addiction-like behaviour, and the potential side effects associated with the treatment. We show that daily treatment with LIR (0.1 mg/kg sc) increases the latency to take heroin, reduces heroin self-administration, prevents escalation of heroin self-administration and reduces drug-induced reinstatement of heroin-seeking behaviour in rats. A 1-h pretreatment time, however, was too short to reduce cue-induced seeking in our study. Moreover, we showed that, while LIR (0.1, 0.3, 0.6 and 1.0 mg/kg sc) supported conditioned taste avoidance of a LIR-paired saccharin cue, it did not elicit intake of the antiemetic kaolin in heroin-naïve or heroin-experienced rats. Further, 0.1 mg/kg LIR did not produce great disruptions in food intake or body weight. Overall, the data show that LIR is effective in reducing heroin taking and heroin seeking at doses that do not cause malaise and have a modest effect on food intake and body weight gain.

The Expression of RAAS Key Receptors, Agtr2 and Bdkrb1, Is Downregulated at an Early Stage in a Rat Model of Wolfram Syndrome.

Wolfram syndrome (WS) 1 is a rare monogenic neurodegenerative disorder caused by mutations in the gene encoding WFS1. Knowledge of the pathophysiology of WS is incomplete and to date, there is no treatment available. Here, we describe early deviations in the renin-angiotensin-aldosterone system (RAAS) and bradykinin pathway (kallikrein kinin system, KKS) observed in a rat model of WS (Wfs1 KO) and the modulative effect of glucagon-like peptide-1 receptor agonist liraglutide (LIR) and anti-epileptic drug valproate (VPA), which have been proven effective in delaying WS progression in WS animal models. We found that the expression of key receptors of the RAAS and KKS, Agtr2 and Bdkrb1, were drastically downregulated both in vitro and in vivo at an early stage in a rat model of WS. Moreover, in Wfs1, KO serum aldosterone levels were substantially decreased and bradykinin levels increased compared to WT animals. Neither treatment nor their combination affected the gene expression levels seen in the Wfs1 KO animals. However, all the treatments elevated serum aldosterone and decreased bradykinin in the Wfs1 KO rats, as well as increasing angiotensin II levels independent of genotype. Altogether, our results indicate that Wfs1 deficiency might disturb the normal functioning of RAAS and KKS and that LIR and VPA have the ability to modulate these systems.

Assessment of the cardioprotective effect of liraglutide on methotrexate induced cardiac dysfunction through suppression of inflammation and enhancement of angiogenesis in rats.

Methotrexate (MTX) is one of the most commonly used anti-cancer drugs for various types of neoplasms. It is associated with multiple cytotoxic effects including nephrotoxicity, hepatotoxicity and cardiotoxicity. Liraglutide (LIR) is a potent anti-diabetic drug and also has antioxidant and anti-inflammatory properties. In this study, we tried to investigate the protective effect of LIR on MTX induced cardiotoxicity and to identify the molecular mechanisms for this protection. Rats were divided into 4 groups, including control group, LIR group, MTX group and LIR + MTX group. ECG was measured then blood samples were taken, and hearts were excised for biochemical and histological investigations. MTX group exhibited a mild non-significant irregular bradycardia, an increase of CK-MB besides a decrease of total antioxidant capacity. MTX administration also resulted in downregulation of vascular endothelial growth factor (VEGF), while caused upregulation of interleukin 1 beta (IL-1B) and interleukin 6 (IL-6) in comparison to the control group. Also, MTX group showed histological abnormalities besides negative VEGF and positive iNOS as detected by immunohistochemical staining compared to the control group. LIR administration could reverse these results. LIR prevented MTX induced cardiotoxicity through its antioxidant and anti-inflammatory properties.

Liraglutide may affect visceral fat accumulation in diabetic rats via changes in FTO, AMPK, and AKT expression

PurposeThe aim of this study is to explore the effects of liraglutide (LRG) on the expression of FTO, AMPK, and AKT in the visceral adipose tissues of obese and diabetic rats and the underlying mechanisms thereof.MethodsThirty SPF-grade, male SD rats were randomly divided into the healthy control, diabetic model (DM), and DM + LRG groups. The DM and DM + LRG groups were administered normal saline and LRG (0.6 mg/kg/d), respectively. After 12 weeks, the body weight of the rats was measured, and their visceral adipose tissues were collected and weighed; the levels of serum biochemical indicators and FTO, AMPK, and AKT in these tissues were then measured using qRT-PCR and western blotting.ResultsCompared to the control group, the body weight and visceral fat accumulation and blood glucose, TG, TC, and LDL-C levels increased significantly, while the HDL-C levels decreased significantly, in the DM group (p < 0.05). After LRG treatment, the HDL-C levels increased significantly, but the levels of the other indicators decreased significantly (p < 0.05). Compared to the control group, the visceral adipose tissue levels of FTO and AKT increased significantly, while the AMPK levels decreased significantly in the DM group (p < 0.05). After LRG treatment, the FTO and AKT levels decreased significantly, and the AMPK levels increased significantly (p < 0.05).ConclusionLRG may activate and inhibit the AMPK and AKT pathways, respectively, and decrease FTO expression, thereby alleviating abdominal obesity in type 2 diabetes.

Liraglutide Alleviates Cognitive Deficit in db/db Mice: Involvement in Oxidative Stress, Iron Overload, and Ferroptosis.

Studies have shown that diabetes is associated with the occurrence of neurodegenerative diseases and cognitive decline. However, there is currently no effective treatment for diabetes-induced cognitive dysfunction. The superior efficacy of liraglutide (LIRA) for cognitive impairment and numerous neurodegenerative diseases has been widely demonstrated. This study determined the effects of LIRA on diabetic cognitive impairment and on the levels of oxidative stress, lipid peroxidation, iron metabolism and ferroptosis in the hippocampus. Mice were injected daily with liraglutide (200μg/kg/d) for 5weeks. LIRA could repair damaged neurons and synapses, and it increased the protein expression levels of PSD 95, SYN, and BDNF. Furthermore, LIRA significantly decreased oxidative stress and lipid peroxidation levels by downregulating the production of ROS and MDA and upregulating SOD and GSH-Px in the serum and hippocampus, and the upregulation of SOD2 expression was also proven. The decreased levels of TfR1 and the upregulation of FPN1 and FTH proteins observed in the LIRA-treated db/db group were shown to reduce iron overload in the hippocampus, whereas the increased expression of Mtft and decreased expression of Mfrn in the mitochondria indicated that mitochondrial iron overload was ameliorated. Finally, LIRA was shown to prevent ferroptosis in the hippocampus by elevating the expression of GPX4 and SLC7A11 and suppressing the excessive amount of ACSL4; simultaneously, the damage to the mitochondria observed by TEM was also repaired. For the first time, we proved in the T2DM model that ferroptosis occurs in the hippocampus, which may play a role in diabetic cognitive impairment. LIRA can reduce oxidative stress, lipid peroxidation and iron overload in diabetic cognitive disorders and further inhibit ferroptosis, thereby weakening the damage to hippocampal neurons and synaptic plasticity and ultimately restoring cognitive function.

В унісон із світовими тенденціями: клінічні аспекти застосування ліраглутиду в комбінації з інсуліном у пацієнтів із цукровим діабетом (огляд літератури і клінічні спостереження)

Надано огляд літератури з питань терапії цукрового діабету 1-го і 2-го типу на основі інкретинового ефекту, про механізми дії, переваги й обмеження нового класу протидіабетичних препаратів — агоністів рецепторів глюкагоноподібного пептиду‑1 (ГПП‑1), про їх клінічне застосування в комбінації з інсуліном, що дозволяє нівелювати негативні ефекти останнього. Наводяться описи успішного клінічного застосування ліраглутиду в пацієнтів, що страждають на цукровий діабет 2-го типу, у випадках неефективно контрольованої глікемії натще, за відсутності компенсації глікемії високими дозами інсуліну й метформіну, а також при кардіоренальному синдромі.

Noninvasive assessment of coronary microvascular dysfunction using SPECT myocardial perfusion imaging and myocardial perfusion entropy quantification in a rodent model of type 2 diabetes

Coronary microvascular dysfunction (CMVD) plays a major role in the occurrence of cardiovascular events (CVE). We recently suggested the clinical potential of myocardial perfusion entropy (MPE) quantification from SPECT myocardial perfusion images (MPI) for the prognosis of CVE occurrence. We hypothesized that the quantification of MPE from SPECT MPI would allow the assessment of CMVD-related MPE variations in a preclinical model of type 2 diabetes (T2D) including treatment with the anti-diabetic incretin liraglutide (LIR). Optimal conditions for the preclinical quantification of MPE using 201Tl SPECT MPI were determined in rats with a T2D-like condition induced by a high-fat diet and streptozotocin injection (feasibility study, n = 43). Using such conditions, echocardiography and post-mortem LV capillary density evaluation were then used in order to assess the effect of LIR and the ability of MPE to assess CMVD (therapeutic study, n = 39). The feasibility study identified dobutamine stress and acute NO synthase and cyclooxygenase inhibition as optimal conditions for the quantification of MPE, with significant increases in MPE being observed in T2D animals (P < 0.01 vs controls). In the therapeutic study, T2D rats were hyperglycemic (5.5 ± 0.5 vs 1.1 ± 0.3g/L for controls, P < 0.001) and had a significantly lower left ventricular ejection fraction (LVEF) (65 ± 4% vs 74 ± 9%, P < 0.01) and LV capillary density (2400 ± 300 vs 2800 ± 600mm-3, P < 0.05). LIR partially restored glycemia (3.9 ± 0.6g/L, P < 0.05 vs controls and T2D), totally prevented LVEF impairment (72 ± 7%, P = NS vs CTL), with no significant effect on capillary density. MPE was significantly increased in T2D rats (7.6 ± 0.5 vs 7.1 ± 0.5, P < 0.05), with no significant improvement in T2D-LIR rats (7.4 ± 0.4, P = NS vs controls and T2D). MPE quantification allowed the preclinical noninvasive assessment of CMVD. Both MPE and capillary density quantification suggested that LIR did not improve T2D-induced CMVD. The relevance of MPE for CMVD assessment warrants further clinical investigation.

Mechanism of and strategy to mitigate liraglutide-mediated positive chronotropy

AimAn adverse side-effect of Liraglutide (LG), a Glucagon-Like Peptide 1 (GLP1)-analog commonly used in treatments for diabetes, is positive chronotropy. The goal of this study is to investigate on the mechanism of this drug-induced chronotropy and explore potential means to mitigate this side-effect so as to maximize the therapeutic benefits from LG. Main methodsExperiments were conducted with: 1) Isolated rabbit hearts in a Langendorff set-up to assess for direct effects of drug actions and 2) Murine cardiomyocytes isolated from the sino-atrial node (SAN) to assess the effects of LG on spontaneous action potential (AP) firing and the hyperpolarization-activated current If. Key findingsLG induced a dose-dependent increase in heart rate. Its effects on sinus node automaticity, which were not suppressed during β-blockade with Propranolol, were abolished by If blockade with Ivabradine. In isolated murine SAN myocytes, LG increased spontaneous AP firing frequency by an increase in diastolic depolarization slope without changing other electrophysiological parameters. SignificanceLG-induced positive chronotropy is partly due to a direct effect on the SAN and is independent of the adrenergic cascade and extrinsic autonomic reflex mechanisms. The direct LG-associated increase in heart rate should be mitigated with If blockers rather than β-blockade.