Cardiovascular disease is a leading cause of death and reduced quality of life, proven by the latest data of the Global Burden of Disease Study, and is only gaining in prevalence worldwide. Clinical trials have identified chronic inflammatory disorders as cardiovascular risks, and recent research has revealed a contribution by various inflammatory cells to vascular oxidative stress. Atherosclerosis and cardiovascular disease are closely associated with inflammation, probably due to the close interaction of inflammation with oxidative stress. Classical therapies for inflammatory disorders have demonstrated protective effects in various models of cardiovascular disease; especially established drugs with pleiotropic immunomodulatory properties have proven beneficial cardiovascular effects; normalization of oxidative stress seems to be a common feature of these therapies. The close link between inflammation and redox balance was also supported by reports on aggravated inflammatory phenotype in the absence of antioxidant defense proteins (e.g., superoxide dismutases, heme oxygenase-1, and glutathione peroxidases) or overexpression of reactive oxygen species producing enzymes (e.g., NADPH oxidases). The value of immunomodulation for the treatment of cardiovascular disease was recently supported by large-scale clinical trials demonstrating reduced cardiovascular mortality in patients with established atherosclerotic disease when treated by highly specific anti-inflammatory therapies (e.g., using monoclonal antibodies against cytokines). Modern antidiabetic cardiovascular drugs (e.g., SGLT2 inhibitors, DPP-4 inhibitors, and GLP-1 analogs) seem to share these immunomodulatory properties and display potent antioxidant effects, all of which may explain their successful lowering of cardiovascular risk.

Objective: Cardiovascular outcome trials demonstrated that GLP-1 (glucagon-like peptide-1) analogs including liraglutide reduce the risk of cardiovascular events in type 2 diabetes mellitus. Whether GLP-1 analogs reduce the risk for atherosclerosis independent of glycemic control is challenging to elucidate as the GLP-1R (GLP-1 receptor) is expressed on different cell types, including endothelial and immune cells. Approach and Results: Here, we reveal the cardio- and vasoprotective mechanism of the GLP-1 analog liraglutide at the cellular level in a murine, nondiabetic model of arterial hypertension. Wild-type (C57BL/6J), global ( Glp1r −/− ), as well as endothelial ( Glp1r f lox/floxxCdh5 cre ) and myeloid cell–specific knockout mice ( Glp1r flox/flox xLysM cre ) of the GLP-1R were studied, and arterial hypertension was induced by angiotensin II. Liraglutide treatment normalized blood pressure, cardiac hypertrophy, vascular fibrosis, endothelial dysfunction, oxidative stress, and vascular inflammation in a GLP-1R–dependent manner. Mechanistically, liraglutide reduced leukocyte rolling on the endothelium and infiltration of myeloid Ly6G − Ly6C + and Ly6G + Ly6C + cells into the vascular wall. As a consequence, liraglutide prevented vascular oxidative stress, reduced S-glutathionylation as a marker of eNOS (endothelial NO synthase) uncoupling, and increased NO bioavailability. Importantly, all of these beneficial cardiovascular effects of liraglutide persisted in myeloid cell GLP-1R-deficient ( Glp1r flox/flox xLysM cre ) mice but were abolished in global ( Glp1r −/− ) and endothelial cell–specific ( Glp1r flox/flox xCdh5 cre ) GLP-1R knockout mice. Conclusions: GLP-1R activation attenuates cardiovascular complications of arterial hypertension by reduction of vascular inflammation through selective actions requiring the endothelial but not the myeloid cell GLP-1R.

Environmental noise is a well‐recognized health risk and part of the external exposome—the World Health Organization estimates that 1 million healthy life years are lost annually in Western Europe alone due to noise‐related complications, including increased incidence of hypertension, heart failure, myocardial infarction, and stroke. Previous data suggest that noise works through two paired pathways in a proposed reaction model for noise exposure. As a nonspecific stressor, chronic low‐level noise exposure can cause a disruption of sleep and communication leading to annoyance and subsequent sympathetic and endocrine stress responses leading to increased blood pressure, heart rate, stress hormone levels, and in particular more oxidative stress, being responsible for vascular dysfunction and representing changes of the internal exposome. Chronic stress generates cardiovascular risk factors on its own such as increased blood pressure, blood viscosity, blood glucose, and activation of blood coagulation. To this end, persistent chronic noise exposure increases cardiometabolic diseases, including arterial hypertension, coronary artery disease, arrhythmia, heart failure, diabetes mellitus type 2, and stroke. The present review discusses the mechanisms of the nonauditory noise‐induced cardiovascular and metabolic consequences, focusing on mental stress signaling pathways, activation of the hypothalamic–pituitary–adrenocortical axis and sympathetic nervous system, the association of these activations with inflammation, and the subsequent onset of oxidative stress and vascular dysfunction. © 2019 BioFactors, 45 (4):495–506, 2019

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Aircraft noise induces vascular and cerebral inflammation and oxidative stress causing hypertension and cardiovascular/cerebral dysfunction. With the present studies, we sought to determine the role of myeloid cells in the vascular vs. cerebral consequences of exposure to aircraft noise. Toxin-mediated ablation of lysozyme M+ (LysM+) myeloid cells was performed in LysMCreiDTR mice carrying a cre-inducible diphtheria toxin receptor. In the last 4d of toxin treatment, the animals were exposed to noise at maximum and mean sound pressure levels of 85 and 72 dB(A), respectively. Flow cytometry analysis revealed accumulation of CD45+, CD11b+, F4/80+, and Ly6G−Ly6C+ cells in the aortas of noise-exposed mice, which was prevented by LysM+ cell ablation in the periphery, whereas brain infiltrates were even exacerbated upon ablation. Aircraft noise-induced increases in blood pressure and endothelial dysfunction of the aorta and retinal/mesenteric arterioles were almost completely normalized by ablation. Correspondingly, reactive oxygen species in the aorta, heart, and retinal/mesenteric vessels were attenuated in ablated noise-exposed mice, while microglial activation and abundance in the brain was greatly increased. Expression of phagocytic NADPH oxidase (NOX-2) and vascular cell adhesion molecule-1 (VCAM-1) mRNA in the aorta was reduced, while NFκB signaling appeared to be activated in the brain upon ablation. In sum, we show dissociation of cerebral and peripheral inflammatory reactions in response to aircraft noise after LysM+ cell ablation, wherein peripheral myeloid inflammatory cells represent a dominant part of the pathomechanism for noise stress-induced cardiovascular effects and their central nervous counterparts, microglia, as key mediators in stress responses.