Peripheral artery disease (PAD) is a manifestation of systemic atherosclerosis. Modifiable risk factors including cigarette smoking, dyslipidemia, diabetes, poor diet quality, obesity, and physical inactivity, along with underlying genetic factors contribute to lower extremity atherosclerosis. Patients with PAD often have coexistent coronary or cerebrovascular disease, and increased likelihood of major adverse cardiovascular events, including myocardial infarction, stroke and cardiovascular death. Patients with PAD often have reduced walking capacity and are at risk of acute and chronic critical limb ischemia leading to major adverse limb events, such as peripheral revascularization or amputation. The presence of polyvascular disease identifies the highest risk patient group for major adverse cardiovascular events, and patients with prior critical limb ischemia, prior lower extremity revascularization, or amputation have a heightened risk of major adverse limb events. Medical therapies have demonstrated efficacy in reducing the risk of major adverse cardiovascular events and major adverse limb events, and improving function in patients with PAD by modulating key disease determining pathways including inflammation, vascular dysfunction, and metabolic disturbances. Treatment with guideline-recommended therapies, including smoking cessation, lipid lowering drugs, optimal glucose control, and antithrombotic medications lowers the incidence of major adverse cardiovascular events and major adverse limb events. Exercise training and cilostazol improve walking capacity. The heterogeneity of risk profile in patients with PAD supports a personalized approach, with consideration of treatment intensification in those at high risk of adverse events. This review highlights the medical therapies currently available to improve outcomes in patients with PAD.

Contemporary Medical Management of Peripheral Artery Disease

Glucagon-like peptide-1 (GLP-1) is an incretin hormone that has undergone a revolutionary turnaround from discovery to clinically approved therapeutic. Rapid progress in drug design and formulation has led from initial development of short- and long-acting drugs suitable for daily or weekly parenteral administration, respectively, through to the most recent approval of an orally active GLP-1 agent. The current review outlines the biological action profile of GLP-1 including the various beneficial metabolic responses in pancreatic and extra-pancreatic tissues, including the gastrointestinal tract, liver, bone and kidney as well as the reproductive cardiovascular and CNS. We then briefly consider clinically approved GLP-1 receptor ligands and recent advances in this field. Given the sustained evolution in the area of GLP-1 drug development and excellent safety profile, as well as the plethora of metabolic benefits, clinical approval for use in diseases beyond diabetes and obesity is very much conceivable.

Metabolic responses and benefits of glucagon-like peptide-1 (GLP-1) receptor ligands

Erectile dysfunction (ED) is a long-term complication of type 2 diabetes (T2D) widely known to affect the quality of life. Several aspects of altered metabolism in individuals with T2D may help to compromise the penile vasculature structure and functions, thus exacerbating the imbalance between smooth muscle contractility and relaxation. Among these, advanced glycation end-products and reactive oxygen species derived from a hyperglycaemic state are known to accelerate endothelial dysfunction by lowering nitric oxide bioavailability, the essential stimulus of relaxation. Although several studies have explained the pathogenetic mechanisms involved in the generation of erectile failure, few studies to date have described the efficacy of glucose-lowering medications in the restoration of normal sexual activity. Herein, we will present current knowledge about the main starters of the pathophysiology of diabetic ED and explore the role of different anti-diabetes therapies in the potential remission of ED, highlighting specific pathways whose activation or inhibition could be fundamental for sexual care in a diabetes setting.

Role of Glucose-Lowering Medications in Erectile Dysfunction.

Glucagon-like peptide-1 (GLP-1) receptor agonists are recently discovered antidiabetic drugs with potent hypoglycemic effects. Among different mechanisms of activity, these compounds were shown to reduce blood glucose by suppression of glucagon secretion and stimulation of glucose-dependent insulin secretion. These antidiabetic agents have a minor risk of hypoglycemia and have been suggested as a second-line therapy to be added to metformin treatment to further optimize glycemic control in diabetes. More recently, scientific evidence suggests that GLP-1 receptor agonists may particularly afford protection from diabetic nephropathy through modulation of the molecular pathways involved in renal impairment and so improve renal function. This additional benefit adds further weight for these compounds to become promising drugs not only for glycemic control but also to prevent diabetic complications. In this review, we have updated evidence on the beneficial effects of GLP-1 receptor agonists on diabetic nephropathy and detailed the underlying pathophysiological mechanisms.

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Renoprotective Effects of Incretin-Based Therapy in Diabetes Mellitus.

Coronary no-reflow damage is caused by endothelial cell damage although little drug is available to intervene in coronary no-reflow. Liraglutide is a kind of anti-diabetic drug and its cardioprotec...

Liraglutide reduces coronary endothelial cells no-reflow damage through activating MAPK/ERK signaling pathway

Recent clinical intervention studies have shown that the GLP1 analogue liraglutide lowers cardiovascular risk, but the underlying mechanism has not yet been fully elucidated. This study investigated the effects of liraglutide on endothelial function in the Ldlr-/- mouse model. Mice (n = 12/group) were fed Western diet (WD) or chow for 12 weeks followed by 4 weeks of treatment with liraglutide (1 mg/kg/day) or vehicle subcutaneously. Weight loss, blood lipid content, plaque burden, vasomotor function of the aorta and gene expression pattern in aorta and brachiocephalic artery were monitored. Liraglutide treatment significantly induced weight loss (P < .0001), decreased blood triglycerides (P < .0001) and total cholesterol (P < .0001) in WD-fed mice but did not decrease plaque burden. Liraglutide also improved endothelium-mediated dilation of the distal thoracis aorta (P = .0067), but it did not affect phenylephrine or sodium nitroprusside responses. Fluidigm analyses of 96 genes showed significantly altered expression of seven genes related to inflammation, vascular smooth muscle cells and extracellular matrix composition in liraglutide-treated animals. We conclude that treatment with liraglutide decreased endothelial dysfunction and that this could be linked to decreased inflammation or regulation of vascular remodelling.

Liraglutide treatment improves endothelial function in the Ldlr−/− mouse model of atherosclerosis and affects genes involved in vascular remodelling and inflammation

The glucagon-like peptide-1 receptor (GLP1R) is expressed in the renal vasculature and known to be downregulated under hypertensive conditions in rats and humans. However, little is known about the regulation in other types of renal pathology involving vascular changes. This study investigates the expression of the GLP1R in renal vasculature after glomerular injury in the nephrotoxic nephritis mouse model, high cholesterol, and atherosclerosis in the Ldlr-/- mouse on Western diet, and ex vivo injury in an organ culture model. The immunohistochemical signal of the GLP1R was significantly decreased in arteries from mice with nephrotoxic nephritis after 42 days compared to 7 days and saline control (P < 0.05). Histological evaluation of kidneys from Ldlr-/- mice on Western diet showed a decreased GLP1R specific immunohistochemical signal (P < 0.05). The dilatory response to liraglutide was decreased in Western diet fed Ldlr-/- mice compared to C57Bl/6J controls (P < 0.05). Organ culture significantly decreased the immunohistochemical signal of the GLP1R (P <0.05) and the expression of Glp1r mRNA (P < 0.005) compared to fresh. Organ cultured vessels showed vascular smooth muscle cell remodelling as Acta2 expression was decreased (P < 0.005) and Ednrb was increased (P < 0.05). In conclusion, nephrotoxic nephritis and hypercholesterolaemia led to decreased GLP1R specific immunohistochemical signal. Ex vivo vascular injury in the organ culture model leads to a decrease in expression of GLP1R expressionand contractile VSMC specific markers and increase in expression of dedifferentiation markers suggestive of an inverse relationship between phenotypic switch of the VSMC and the expression of the GLP1R; however, the causal relationship remains elusive.

Decreased expression of the GLP-1 receptor after segmental artery injury in mice

The GLP-1 receptor (GLP-1R) in the kidney is expressed exclusively in vascular smooth muscle cells in arteries and arterioles. Downstream effects of the activation of the renal vascular GLP-1R are elusive but may involve regulation of the renin-angiotensin-aldosterone system (RAAS). The expression of Ren1 in the mouse renal vasculature was investigated by in situ hybridization after a single subcutaneous dose of liraglutide, semaglutide and after repeated injections of liraglutide. Single and repeated exposure to GLP-1R agonists induced expression of Ren1 in the renal vascular smooth muscle cell compartment compared with vehicle injected controls (p < .0001) for both semaglutide and liraglutide. The present data show a robust induction of Ren1 expression in the vascular smooth muscle cells of the kidney after single and repeated GLP-1R activation and this renin recruitment may be involved in the effects of GLP-1R agonist treatment on kidney disease.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/edm2.234

Katrine Dahl Bjørnholm

Papers

Liraglutide treatment improves endothelial function in the Ldlr−/− mouse model of atherosclerosis and affects genes involved in vascular remodelling and inflammation

Decreased expression of the GLP-1 receptor after segmental artery injury in mice

Activation of the renal GLP-1R leads to expression of Ren1 in the renal vascular tree

Distinct Fibroblast Subtypes Populate Specific Brain Barriers