Glucagon-Like Peptide Receptor Agonist Inhibits Angiotensin II-Induced Proliferation and Migration in Vascular Smooth Muscle Cells and Ameliorates Phosphate-Induced Vascular Smooth Muscle Cells Calcification

BACKGRUOUND

Glucagon-like peptide-1 receptor agonist (GLP-1RA), which is a therapeutic agent for the treatment of type 2 diabetes mellitus, has a beneficial effect on the cardiovascular system.

METHODS

To examine the protective effects of GLP-1RAs on proliferation and migration of vascular smooth muscle cells (VSMCs), A-10 cells exposed to angiotensin II (Ang II) were treated with either exendin-4, liraglutide, or dulaglutide. To examine the effects of GLP-1RAs on vascular calcification, cells exposed to high concentration of inorganic phosphate (Pi) were treated with exendin-4, liraglutide, or dulaglutide.

RESULTS

Ang II increased proliferation and migration of VSMCs, gene expression levels of Ang II receptors AT1 and AT2, proliferation marker of proliferation Ki-67 (Mki-67), proliferating cell nuclear antigen (Pcna), and cyclin D1 (Ccnd1), and the protein expression levels of phospho-extracellular signal-regulated kinase (p-Erk), phospho-c-JUN N-terminal kinase (p-JNK), and phospho-phosphatidylinositol 3-kinase (p-Pi3k). Exendin-4, liraglutide, and dulaglutide significantly decreased the proliferation and migration of VSMCs, the gene expression levels of Pcna, and the protein expression levels of p-Erk and p-JNK in the Ang II-treated VSMCs. Erk inhibitor PD98059 and JNK inhibitor SP600125 decreased the protein expression levels of Pcna and Ccnd1 and proliferation of VSMCs. Inhibition of GLP-1R by siRNA reversed the reduction of the protein expression levels of p-Erk and p-JNK by exendin-4, liraglutide, and dulaglutide in the Ang II-treated VSMCs. Moreover, GLP-1 (9-36) amide also decreased the proliferation and migration of the Ang II-treated VSMCs. In addition, these GLP-1RAs decreased calcium deposition by inhibiting activating transcription factor 4 (Atf4) in Pi-treated VSMCs.

CONCLUSION

These data show that GLP-1RAs ameliorate aberrant proliferation and migration in VSMCs through both GLP-1Rdependent and independent pathways and inhibit Pi-induced vascular calcification.

Eosinophil-related diseases during treatment with glucagon-like peptide one receptor (GLP-1 RA): a case report and review of the literature

Glucagon-like peptide one-receptor agonists (GLP-1 RA) are drugs that differ in their pharmacological composition and homology to human GLP-1 and are used most frequently for the treatment of type 2 diabetes and weight loss. There are isolated reports of eosinophilic adverse reactions associated with GLP-1 RA. We present the case of a 42-year-old female patient who, after starting weekly subcutaneous semaglutide, developed eosinophilic fasciitis with favorable clinical evolution after the discontinuation of semaglutide and the initiation of immunosuppression. A review of the eosinophilic adverse events that have been previously reported with GLP-1 RA is provided.

Sleeve Gastrectomy Improves High-Fat Diet-Associated Hepatic Steatosis Independent of the Glucagon-like-Petpide-1 Receptor in Rats

BACKGROUND

The gastrointestinal hormone glucagon-like peptide-1 (GLP-1) is increased after sleeve gastrectomy (SG). Rat and clinical studies support, while mouse studies refute, a role for GLP-1R signaling after SG. Therefore, we developed a global GLP-1R knockout (KO) rat to test the hypothesis that a functional GLP-1R is critical to induce weight loss and metabolic disease improvement after SG.

METHODOLOGY

A 4 bp deletion was created in exon 2 of the GLP-1R gene on a Lewis strain background to create a global GLP-1R KO rat. KO and Lewis rats were placed on a high-fat or low-fat diet and phenotyped followed by SG or Sham surgery and assessed for the effect of GLP-1R KO on surgical and metabolic efficacy.

RESULTS

Loss of the GLP-1R created an obesity-prone rodent without changes in energy expenditure. Both male and female KO rats had significantly greater insulin concentrations after an oral glucose gavage, augmented by a high-fat diet, compared to Lewis rats despite similar glucose concentrations. GLP-1R KO caused hepatomegaly and increased triglyceride deposition compared to Lewis rats. We found no difference between SG GLP-1R KO and Lewis groups when considering efficacy on body weight, glucose tolerance, and a robustly preserved improvement in fatty liver disease.

CONCLUSIONS

Loss of the GLP-1R in rats resulted in increased adiposity, insulin resistance, and severe steatosis. A functional GLP-1R is not critical to the metabolic efficacy of SG in Lewis rats, similar to mouse studies, but importantly including steatosis, supporting a GLP-1R-independent mechanism for the improvement in fatty liver disease after SG.

Comparison of Sodium-Glucose Cotransporter 2 Inhibitors and Glucagon-like Peptide Receptor Agonists for Atrial Fibrillation in Type 2 Diabetes Mellitus: Systematic Review With Network Meta-analysis of Randomized Controlled Trials

ABSTRACT

Atrial fibrillation (AF) is a major public health concern with a rising prevalence. Although sodium-glucose cotransporter 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) have shown the respective favorable effects on reducing the occurrence of AF/atrial flutter (AFL), comparative protective AF/AFL effects between above 2 novel antidiabetic agents remain unavailable. Thus, we aimed to evaluate the comparative efficacy of SGLT2is and GLP-1RAs in reducing the risk of AF/AFL in patients with type 2 diabetes and estimate relative rankings of interventions. PubMed, Embase, and ClinicalTrials.gov were searched up to December 1, 2020. All available randomized controlled trials comparing SGLT2is and GLP-1RAs with one another or placebo in patients with type 2 diabetes were included. Pooled results were shown as risk ratios (RRs) with 95% confidence intervals (CIs). We used a frequentist network meta-analysis to evaluate the outcomes of interests. Thirty-six randomized controlled trials including 85,701 participants with type 2 diabetes were identified. Compared with placebo, both SGLT2is (RR: 0.82, 95% CI, 0.68-0.99) and GLP-1RAs (RR: 0.86, 95% CI, 0.76-0.97; RR long-acting ones: 0.87, 95% CI, 0.76-0.99; RR short-acting ones: 0.72, 95% CI, 0.45-1.14) significantly reduced AF/AFL risk. No significant difference between SGLT2is and GLP-1RAs was noted (RR: 0.95, 95% CI, 0.76-1.2). Compared with placebo, results from the analysis showed an RR of 0.72 (95% CI, 0.45-1.14) for short-acting GLP-1RAs and 0.87 (95% CI, 0.76-0.99) for long-acting GLP-1RAs in reducing the risk of AF/AFL. Compared with placebo, both SGLT2is and GLP-1RAs possessed favorable effects on reducing the risk of AF/AFL. However, no difference was observed when comparisons were made between them. In addition, long-acting ones may confer a more pronounced AF/AFL reduction benefit compared with placebo.

Exendin-4, a glucagon-like peptide receptor agonist, facilitates osteoblast differentiation via connexin43

PURPOSE

To investigate whether exendin-4 (Ex-4), a glucagon-like peptide 1 receptor (GLP-1R) agonist, affects connexin 43 (Cx43) expression in osteoblasts, and determine the specific mechanism underlying Cx43 modulation by Ex-4.

METHODS

Osteoblast-like MC3T3-E1 cells were treated with Ex-4 with or without GLP-1R antagonist. We assessed Cx43 expression using RT-PCR, western blotting, and confocal microscopy; visualized intercellular communication using Lucifer yellow dye transfer assay; evaluated osteoblast differentiation using alkaline phosphatase and Alizarin red S (ARS) staining. Cx43 silencing or overexpression was investigated via RNA-interference or adenovirus infection. The mechanism underlying Cx43 regulation by Ex-4 was determined via treatment with either Src kinase inhibitor, KX2-391, Akt activator, sc79, or inhibitor, LY294002.

RESULTS

Ex-4 treatment enhanced Cx43 expression and gap junctional intercellular communication in MC3T3-E1 cells. GLP-1R antagonist pretreatment abrogated the induction of Cx43 expression. Cx43 silencing significantly decreased ARS staining intensity in Ex-4-treated cells, whereas overexpression enhanced cell differentiation. Treatment with KX2-391 reduced both the Ex-4-induced increase of Cx43 expression and p-Akt protein levels. sc79 upregulated Cx43 expression, while LY294002 attenuated Cx43 upregulation by Ex-4.

CONCLUSIONS

Induced Cx43 expression in osteoblasts via the Src-Akt signaling pathway illustrates the underlying mechanism for promoting osteoblast differentiation by Ex-4.

Semaglutide: A Novel Oral Glucagon-Like Peptide Receptor Agonist for the Treatment of Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is a complex and chronic condition that requires continuous medical care. Uncontrolled hyperglycemia can lead to serious microvascular and macrovascular complications, such as coronary artery disease, peripheral arterial disease, and stroke. Type 2 DM occurs when the pancreas is unable to produce adequate insulin to regulate glucose levels and when there is a decrease in sensitivity to insulin in the body. Insufficient glucagon-like peptide (GLP-1), a normal body hormone, plays an important role in the pathophysiology of DM. The introduction of the GLP-1 receptor agonists expanded therapeutic options in achieving glycemic control in adult patients. In 2005, the US Food and Drug Administration approved exenatide as the first injectable formulation, which led to the advancement of other injectable formulations within the class of GLP-1 receptor agonists. In 2019, semaglutide was approved as the first oral GLP-1 receptor agonist addressing the unmet needs in patients who benefit from therapy with this therapeutic class yet are unwilling to use an injectable drug. This article will provide an overview of the GLP-1 receptor agonists, including the pharmacology of semaglutide, its clinical evidence and role in therapy in type 2 DM.

Systematic Review of Glucagon-Like Peptide One Receptor Agonist Liraglutide of Subjects with Heart Failure with Reduced Left Ventricular Ejection Fraction

BACKGROUND

The major cardiovascular outcome trials on glucagon-like peptide one-receptor agonists have examined its effect on hospitalization of subjects with heart failure; however, very limited trials have been conducted on subjects with reduced left ventricular ejection fraction (r- LVEF) as a primary outcome.

OBJECTIVE

We have conducted a systematic review of two major (FIGHT and LIVE) placebo-controlled trials of liraglutide and its clinical effect on the ejection fraction of subjects with heart failure.

METHODS

Medline data was retrieved for trials involving liraglutide from 2012 to 2020. The inclusion criteria for trials were: subjects with or without type 2 diabetes mellitus (T2DM), subjects with heart failure with rLVEF, major trials (phase II or III) on liraglutide, trials included liraglutide with defined efficacy primary outcome of patients with heart failure with rLVEF. The search was limited to the English language, whereby two trials [FIGHT and LIVE] had been included and two trials were excluded due to different primary outcomes. Participants (541) had been randomized for either liraglutide or placebo for 24 weeks.

RESULTS

In the FIGHT trial the primary intention-to-treat, sensitivity, and diabetes subgroup analyses have shown no significant between-group difference in the global rank scores (mean rank of 146 in the liraglutide group versus 156 in the placebo group; Wilcoxon rank-sum P=.31), number of deaths, re-hospitalizations for heart failure, or the composite of death or change in NT-pro BNP level (P= .94). In the LIVE trial, the change in the left ventricular ejection fraction (LVEF) from baseline to week 24 was not significantly different between treatment groups. The overall discontinuation rate of liraglutide was high in the FIGHT trial (29%, 86) as compared to that in the LIVE trial (11.6%, 28).

CONCLUSION

FIGHT and LIVE trials have demonstrated that liraglutide use in subjects with heart failure and rLVEF was implicated with an increased adverse risk of heart failure-related outcomes.