PGC1α Regulates the Endothelial Response to Fluid Shear Stress via Telomerase Reverse Transcriptase Control of Heme Oxygenase-1

AbstractFluid shear stress (FSS) is known to mediate multiple phenotypic changes in the endothelium. Laminar FSS (undisturbed flow) is known to promote endothelial alignment to flow that is key to stabilizing the endothelium and rendering it resistant to atherosclerosis and thrombosis. The molecular pathways responsible for endothelial responses to FSS are only partially understood. Here we have identified peroxisome proliferator gamma coactivator-1α (PGC-1α) as a flow-responsive gene required for endothelial flow alignment in vitro and in vivo. Compared to oscillatory FSS (disturbed flow) or static conditions, laminar FSS (undisturbed flow) increased PGC-1α expression and its transcription…

Short‐term e‐cigarette vapor exposure causes vascular oxidative stress and dysfunction ‐ evidence for a close connection to brain damage and a key role of the phagocytic NADPH oxidase (NOX‐2)

Differential effects of diabetes on the expression of the gp91phox homologues nox1 and nox4.

The nox2-dependent NADPH oxidase was shown to be a major superoxide source in vascular disease, including diabetes. Smooth muscle cells of large arteries lack the phagocytic gp91phox subunit of the enzyme; however, two homologues have been identified in these cells, nox1 and nox4. It remained to be established whether also increases in protein levels of the nonphagocytic NADPH oxidase contribute to increased superoxide formation in diabetic vessels. To investigate changes in the expression of these homologues, we measured their expression in aortic vessels of type I diabetic rats. Eight weeks after streptozotocin treatment, we found a doubling in nox1 protein expression, while the expressio…

Duffy antigen receptor for chemokines (Darc) polymorphism regulates circulating concentrations of monocyte chemoattractant protein-1 and other inflammatory mediators

AbstractTo identify the genetic basis of circulating concentrations of monocyte chemoattractant protein-1 (MCP-1), we conducted genome-wide association analyses for MCP-1 in 3 independent cohorts (n = 9598). The strongest association was for serum MCP-1 with a nonsynonymous polymorphism, rs12075 (Asp42Gly) in DARC, the gene for Duffy antigen receptor for chemokines, a known vascular reservoir of proinflammatory cytokines (minor allele frequency, 45.6%; P < 1.0 * 10−323). This association was supported by family-based genetic linkage at a locus encompassing the DARC gene (genome-wide P = 8.0 * 10−13). Asp42Gly accounted for approximately 20% of the variability in serum MCP-1 concentration…

Relation of Multiple Inflammatory Biomarkers to Incident Atrial Fibrillation

Basic and clinical studies have suggested that inflammation predisposes to atrial fibrillation (AF). We assessed the association of 12 circulating inflammatory biomarkers (i.e., C-reactive protein, fibrinogen, interleukin-6, intercellular adhesion molecule-1, lipoprotein-associated phospholipase A2 [mass and activity], monocyte chemoattractant protein-1, myeloperoxidase, CD40 ligand, osteoprotegerin, P-selectin, and tumor necrosis factor receptor II) with incident AF in 2863 Framingham Offspring Study participants (mean age 60.7 years, SD = 9.4, 55% women). During follow-up (median 6 years), 148 participants (43% women) developed incident AF. In the multivariable proportional hazards models…

Clinical correlates of change in inflammatory biomarkers: The Framingham Heart Study

Objectives: Traditional clinical risk factors are associated with inflammation cross-sectionally, but associations of longitudinal variation in inflammatory biomarkers with corresponding changes in clinical risk factors are incompletely described. We sought to analyze clinical factors associated with change in inflammation in the community.Methods: We studied 3013 Framingham Offspring (n = 2735) and Omni Cohort (n = 278) participants (mean age 59 years, 55% women, 9% ethnic/racial minority) who attended two consecutive examination cycles (mean 6.7 years apart). We selected ten inflammatory biomarkers representing distinctive biological functions: C-reactive protein (CRP), intercellular adhe…

Effects of tobacco cigarettes, e-cigarettes, and waterpipe smoking on endothelial function and clinical outcomes

Abstract Tobacco smoking is a leading cause of non-communicable disease globally and is a major risk factor for cardiovascular disease (CVD) and lung disease. Importantly, recent data by the World Health Organizations (WHO) indicate that in the last two decades global tobacco use has significantly dropped, which was largely driven by decreased numbers of female smokers. Despite such advances, the use of e-cigarettes and waterpipes (shisha, hookah, narghile) is an emerging trend, especially among younger generations. There is growing body of evidence that e-cigarettes are not a harm-free alternative to tobacco cigarettes and there is considerable debate as to whether e-cigarettes are saving …

Short-term e-cigarette vapour exposure causes vascular oxidative stress and dysfunction: evidence for a close connection to brain damage and a key role of the phagocytic NADPH oxidase (NOX-2)

Abstract Aims Electronic (e)-cigarettes have been marketed as a ‘healthy’ alternative to traditional combustible cigarettes and as an effective method of smoking cessation. There are, however, a paucity of data to support these claims. In fact, e-cigarettes are implicated in endothelial dysfunction and oxidative stress in the vasculature and the lungs. The mechanisms underlying these side effects remain unclear. Here, we investigated the effects of e-cigarette vapour on vascular function in smokers and experimental animals to determine the underlying mechanisms. Methods and results Acute e-cigarette smoking produced a marked impairment of endothelial function in chronic smokers determined b…

Pathophysiological role of oxidative stress in systolic and diastolic heart failure and its therapeutic implications

Abstract Systolic and diastolic myocardial dysfunction has been demonstrated to be associated with an activation of the circulating and local renin–angiotensin–aldosterone system (RAAS), and with a subsequent inappropriately increased production of reactive oxygen species (ROS). While, at low concentrations, ROS modulate important physiological functions through changes in cellular signalling and gene expression, overproduction of ROS may adversely alter cardiac mechanics, leading to further worsening of systolic and diastolic function. In addition, vascular endothelial dysfunction due to uncoupling of the nitric oxide synthase, activation of vascular and phagocytic membrane oxidases or mit…

Cigarette Smoking Is Related to Endothelial Dysfunction of Resistance, but Not Conduit Arteries in the General Population—Results From the Gutenberg Health Study

Aims: Cigarette smoking is one of the most complex and least understood cardiovascular risk factors. Importantly, differences in the tobacco-related pathophysiology of endothelial dysfunction, an early event in atherogenesis, between circulatory beds remain elusive. Therefore, this study evaluated how smoking impacts endothelial function of conduit and resistance arteries in a large population-based cohort.Methods and results: 15,010 participants (aged 35–74 years) of the Gutenberg Health Study were examined at baseline from 2007 to 2012. Smoking status, pack-years of smoking, and years since quitting smoking were assessed by a computer-assisted interview. Endothelial function of conduit an…

Suppression of the JNK Pathway by Induction of a Metabolic Stress Response Prevents Vascular Injury and Dysfunction

Background— Oxidative injury and dysfunction of the vascular endothelium are early and causal features of many vascular diseases. Single antioxidant strategies to prevent vascular injury have met with mixed results. Methods and Results— Here, we report that induction of a metabolic stress response with adenosine monophosphate kinase (AMPK) prevents oxidative endothelial cell injury. This response is characterized by stabilization of the mitochondrion and increased mitochondrial biogenesis, resulting in attenuation of oxidative c-Jun N-terminal kinase (JNK) activation. We report that peroxisome proliferator coactivator 1α is a key downstream target of AMPK that is both necessary and suffici…

Meta-Analysis of Genome-Wide Association Studies in >80 000 Subjects Identifies Multiple Loci for C-Reactive Protein Levels

Background— C-reactive protein (CRP) is a heritable marker of chronic inflammation that is strongly associated with cardiovascular disease. We sought to identify genetic variants that are associated with CRP levels. Methods and Results— We performed a genome-wide association analysis of CRP in 66 185 participants from 15 population-based studies. We sought replication for the genome-wide significant and suggestive loci in a replication panel comprising 16 540 individuals from 10 independent studies. We found 18 genome-wide significant loci, and we provided evidence of replication for 8 of them. Our results confirm 7 previously known loci and introduce 11 novel loci that are implicated in p…