Induction and activation of nitric oxide (NO) synthases (NOS) and excessive production of NO are common features of almost all diseases associated with infection and acute or chronic inflammation, although the contribution of NO to the pathophysiology of these diseases is highly multifactorial and often still a matter of controversy. Because of its direct impact on tissue oxygenation and cellular oxygen (O 2 ) consumption and redistribution, the ability of NO to regulate various aspects of hypoxia-induced signaling has received widespread attention. Conditions of tissue hypoxia and the activation of hypoxia-inducible factors (HIF) have been implicated in hypoxia or in cancer biology, but are also being increasingly recognized as important features of acute and chronic inflammation. Thus, the activation of HIF transcription factors has been increasingly implicated in inflammatory diseases, and recent studies have indicated its critical importance in regulating phagocyte function, inflammatory mediator production, and regulation of epithelial integrity and repair processes. Finally, HIF also appears to contribute to important features of tissue fibrosis and epithelial-to-mesenchymal transition, processes that are associated with tissue remodeling in various non-malignant chronic inflammatory disorders. In this review, we briefly summarize the current state of knowledge with respect to the general mechanisms involved in HIF regulation and the impact of NO on HIF activation. Secondly, we will summarize the major recent findings demonstrating a role for HIF signaling in infection, inflammation, and tissue repair and remodeling, and will address the involvement of NO. The growing interest in hypoxia-induced signaling and its relation with NO biology is expected to lead to further insights into the complex roles of NO in acute or chronic inflammatory diseases and may point to the importance of HIF signaling as key feature of NO-mediated events during these disorders. Hypoxia, Oxygen Sensing and InflammationDramatic changes in metabolism including increased generation of reactive oxygen and nitrogen species (ROS/RNS), depletion of local nutrients, and an increased demand for oxygen (O 2 ) are characteristic features of the inflammatory response [1]. Increased metabolic activity in inflamed tissue results, in part, from the recruitment of myeloid cells, such as neutrophils and macrophages, to inflammatory lesions and their subsequent involvement in phagocytosis and inflammatory mediator release [2]. These processes, © 2010 Elsevier Inc. All rights reserved. 1 Corresponding author: Department of Pathology, D205 Given Building, 89 Beaumont Avenue, Burlington,.. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the...

BackgroundThe American Heart Association's Life's Simple 7 metric is being used to track the population's cardiovascular health (CVH) toward a 2020 goal for improvement. The metric includes body mass index (BMI), blood pressure, cholesterol, glucose, physical activity (PA), cigarette smoking, and diet. We hypothesized a lower risk of venous thromboembolism (VTE) with favorable Life's Simple 7 scores.Methods and ResultsREGARDS recruited 30 239 black and white participants ≥45 years of age across the United States in 2003–2007. A 14‐point summary score for Life's Simple 7 classified participants into inadequate (0 to 4 points), average (5 to 9 points), and optimal (10 to 14 points) categories. Hazard ratios (HRs) of incident VTE were calculated for these categories, adjusting for age, sex, race, income, education, and region of residence. For comparison, HRs of VTE were calculated using the Framingham 10‐year coronary risk score. There were 263 incident VTE cases over 5.0 years of follow‐up; incidence rates per 1000 person‐years declined from 2.9 (95% confidence interval [CI], 2.3 to 3.7) among those in the inadequate category to 1.8 (95% CI, 1.4 to 2.4) in the optimal category. Compared to the inadequate category, participants in the average category had a 38% lower VTE risk (95% CI, 11 to 57) and participants in the optimal category had a 44% lower risk (95% CI, 18 to 62). The individual score components related to lower VTE risk were ideal PA and BMI. There was no association of Framingham Score with VTE.ConclusionsLife's Simple 7, a CVH metric, was associated with reduced VTE risk. Findings suggest that efforts to improve the population's CVH may reduce VTE incidence.

BackgroundAdaptive immunity has been implicated in atherosclerosis in animal models and small clinical studies. Whether chronic immune activation is associated with atherosclerosis in otherwise healthy individuals remains underexplored. We hypothesized that activation of adaptive immune responses, as reflected by higher proportions of circulating CD4+ memory cells and lower proportions of naive cells, would be associated with subclinical atherosclerosis.Methods and FindingsWe examined cross-sectional relationships of circulating CD4+ naive and memory T cells with biomarkers of inflammation, serologies, and subclinical atherosclerosis in 912 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Circulating CD4+ naive cells were higher in women than men and decreased with age (all p-values <0.0001). European-Americans had higher levels of naive cells and lower levels of memory cells compared with African-Americans and Hispanic-Americans (all p-values ≤0.0005). Lower naive/higher memory cells were associated with interleukin-6 levels. In multivariate models, cytomegalovirus (CMV) and H. Pylori titers were strongly associated with higher memory and lower naive cells (all p-values <0.05). Higher memory cells were associated with coronary artery calcification (CAC) level in the overall population [β-Coefficient (95% confidence interval (CI))  = 0.20 (0.03, 0.37)]. Memory and naive (inversely) cells were associated with common carotid artery intimal media thickness (CC IMT) in European-Americans [memory: β =  0.02 (0.006, 0.04); naive: β = −0.02 (−0.004, −0.03)].ConclusionsThese results demonstrate that the degree of chronic adaptive immune activation is associated with both CAC and CC IMT in otherwise healthy individuals, consistent with the known role of CD4+ T cells, and with innate immunity (inflammation), in atherosclerosis. These data are also consistent with the hypothesis that immunosenescence accelerates chronic diseases by putting a greater burden on the innate immune system, and suggest the importance of prospective studies and research into strategies to modulate adaptive immune activation in chronic disease states such as atherosclerosis.

Background Inflammation biomarkers are associated with the venous thromboembolism (VTE) risk factors obesity and age, however the relationships of inflammation with VTE risk remain controversial. Objectives To examine associations of four inflammation biomarkers, C-reactive protein (CRP), serum albumin, white blood cell count (WBC), and platelet count (PLTC), with incident VTE, and determine whether they mediate the association of age or obesity with VTE. Patients/Methods Hazards models adjusted for VTE risk factors were used to calculate prospective associations of each biomarker with incident VTE in 30,239 participants of the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. Mediation of the associations of obesity and age with VTE were examined by bootstrapping. Over 4.6 years, there were 268 incident VTE events. Adjusting for VTE risk factors, the hazard ratio (HR) (95% confidence interval (CI)) was 1.25 (1.09, 1.43) per standard deviation (SD) higher log-CRP and 1.25 (1.06, 1.48) per SD lower albumin, with no associations for WBC or PLTC. The association of BMI, but not age, with VTE was partially mediated by CRP and albumin. In risk factor-adjusted models, the percent attenuation of the BMI HR for VTE by introducing CRP or albumin to the models was 15.4% (95% CI: 7.7%, 33.3%) and 41.0% (95% CI: 12.8%, 79.5%), respectively. Conclusion Higher CRP and lower serum albumin were associated with increased VTE risk, and statistically mediated part of the association of BMI with VTE. These data suggest inflammation may be a potential mechanism underlying the relationship of obesity and VTE risk.

BackgroundAlthough T‐helper type 1 (Th1) cells are considered important in atherosclerosis, the relationships between Th1 and Th2 cells and atherosclerosis have not been examined in population‐based studies.Methods and ResultsWe measured Th cells as a percentage of lymphocytes by flow cytometry using CD4 staining (%CD4) in 917 participants of the Multi‐Ethnic Study of Atherosclerosis. We also measured interferon gamma–positive and interleukin‐4‐positive CD4+ cells, representing Th1 and Th2 subpopulations (%Th1 and %Th2), respectively. We found that %CD4 was 1.5% lower per 10 years of age (P<0.0001). Whites had higher %CD4 and lower %Th1 and %Th2 values than other race/ethnic groups. Body mass index (BMI) and blood pressure were associated with %CD4, but no traditional cardiovascular disease (CVD) risk factors were associated with %Th1 or %Th2. In multivariable models, the major independent variable associated with %Th1 was cytomegalovirus (CMV) antibody titer, with minor contributions from age, sex, seasonality, and interleukin‐6. In models with coronary artery calcification level as the outcome, significant independent variables included age, sex, smoking status, and %Th1 (β=0.25; P≤0.01). Both %Th1 and %Th2 were associated with common carotid intimal media thickness (β=0.02 and −0.02, respectively; both P<0.05), as were age, sex, race/ethnicity, blood pressure, and BMI.ConclusionsTh1 bias is associated with subclinical atherosclerosis in a multiethnic population. The main Th1 correlate was CMV infectious burden. These findings are consistent with a role of Th1 cells in atherosclerosis and suggest the importance of prospective studies of T‐helper cell biasing in CVD.