Citations

Abstract Rationale High-attenuation area (HAA) is a computed tomography (CT) tool that correlates with lung inflammation and fibrosis. Systemic molecular correlates of HAA (e.g., plasma proteins) may inform biological processes involved in interstitial lung disease. Objectives To identify plasma proteins that associate with HAA and correlate with a higher probability of developing new-onset fibrotic or subpleural interstitial lung abnormalities (ILAs). Methods Plasma protein levels were measured using a semiquantitative aptamer-based platform in MESA (the Multi-Ethnic Study of Atherosclerosis; N = 5,486) and SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study; N = 1,781). Linear regression models identified HAA-associated proteins after adjustment for demographic and socioeconomic factors, CT scanner parameters, study center, and batch. Associations of HAA-related proteins with new-onset fibrotic or subpleural ILAs were examined in MESA participants with ILA assessments on full-lung CT 10 years later. Immunohistochemical staining of select proteins was performed in lung tissue from pulmonary fibrosis cases. Measurements and Main Results There were 75 proteins detected that were significantly associated with HAA in MESA and SPIROMICS. Gene Ontology analysis of these proteins identified processes involved in immune cell chemotaxis and cellular growth and apoptosis. Seven proteins were associated with a higher probability of new-onset fibrotic or subpleural ILAs in MESA, and two of these, junctional adhesion molecule-like protein and GTP cyclohydrolase 1 feedback regulatory protein, stained in areas of fibrosis in lung tissue from patients with interstitial lung disease. Conclusions Plasma proteins associated with more HAA are involved in immune and cellular processes and associate with new-onset fibrotic-subpleural ILA.

Background: The new 2013 ACC/AHA cholesterol guidelines recommend statin therapy to reduce atherosclerotic cardiovascular disease. Statins inhibit cholesterol biosynthesis which may impair gonadal steroidogenesis. Higher levels of estradiol (E2) and lower levels of sex hormone binding globulin (SHBG) are associated with greater central obesity, metabolic syndrome and diabetes in both men and postmenopausal women. There is however limited information regarding the impact of statins on endogenous sex hormones in large population studies. Methods: We included 3163 men and 1977 women from the baseline examination of the MESA study who had measurement of serum sex hormones: total and bioavailable testosterone (T), E2, dehydroepiandrosterone (DHEA) and SHBG, and excluded those on hormone replacement therapy and non-statin lipid medications. Results: Of the 5140 individuals examined, statin users (n=812) were 67 + 9 years old, 57% males, 41% Whites, 29% Blacks, 11% Chinese and 19% Hispanics. After adjustment for age, gender and race, total cholesterol, HDL-c and BMI, compared to non-users of statins, statin users had significantly lower SHBG by 4.5 nmol/L (95% CI; -6.1, -2.9) and DHEAS by 0.9 nmol/L (95% CI; -1.4, -0.4). No significant gender interaction with statin was seen. No association was noted between statin use and E2, total and bioavailable T. Conclusion: Statin use is associated inversely with serum SHBG and DHEA levels. This is particularly interesting in light of the association of statin use and diabetes, raising the possibility of mediation by endogenous hormones.

Background: Cellular adhesion molecules (CAM) have a central role in the accumulation of circulating leukocytes at sites of vascular injury, infection and/ inflammation, and have been associated with the development of atherosclerotic plaque and coronary artery disease in mature adults. Objective: To test the hypothesis that higher overall circulating CAM levels in young adults predict cardiovascular disease (CVD) events over the next 18 years. Method: We measured several circulating CAM molecules (ICAM-1, P-selectin, E-selectin and VCAM) in the Coronary Artery Risk Development in Young Adults (CARDIA) study at exam year 7 (1992-93, black and white men and women, CVD-free, mean age 32, range 25-37 years, n=2428) and monitored incident CVD events (n=70, including coronary heart disease, stroke, and heart failure, adjudicated based on medical records) through exam year 25, mean age of 50 years. We ranked each CAM in quintiles (coded 0-4) and summed the ranks across CAMs into an index to examine the association with incident CVD with Cox regression models. Results: Unadjusted cumulative CVD event rates were 1.6% (sum of CAM quartile ranks 0-8: 22 events in 1353 participants), 2.3% (sum of ranks 9-12: 29/813), and 7.3% (sum of ranks 13-16: 19/262). In proportional hazards regression analysis adjusted for year 7 age, sex, race, clinic, education, smoking, diet, physical activity, body mass index, blood pressure, blood lipids, and blood glucose, sum of ranks 13-16 were associated with a higher risk of CVD compared to the referent (rank sum 0-8) (See Table). Conclusion: High levels of circulating CAMs at an early stage of adulthood (mean age 32, range 25-37 years) were associated with an increased risk of incident CVD events. CAMs may be an early biomarker for development of subclinical CVD, even in CVD-free young adults with low atherosclerosis burden and decades prior to the development of clinical CVD.

The effect of head-down neck flexion on forearm and calf blood flow was determined in 10 healthy male subjects. The subject lay prone, with the neck slightly extended and the chin resting on a soft-padded support at the edge of the table. The chin support was then removed, and the subject maximally flexed and lowered the neck. This was followed by return to the initial position. Neck flexion caused a rapid decrease in blood flow in both forearm and calf; at 30 s this averaged 39 and 35%, respectively. The flow in both forearm and calf gradually recovered as the neck flexion was sustained and approached the control values at the end of 10 min. The blood flow at the ankle was unchanged, indicating that the decrease occurred in the skeletal muscles. The arterial blood pressure and heart rate were unchanged; thus the decrease in flow was due to vasoconstriction. The fact that the decrease was evident as soon as the head was lowered indicated that it was nervously mediated. Neither contraction of the flexor muscles of the neck nor venous congestion of the head, in the absence of the head-down position, altered the blood flow. Although the mechanism of the decrease in flow has not been determined, the studies demonstrate that in response to certain stimuli, the resistance vessels in the skeletal muscles of the forearm and calf undergo a similar nervously mediated vasoconstriction.

Ten normal subjects performed a 90-s isometric exercise [20, 30, and 40% of maximal voluntary contraction (MVC) of the flexor muscle of the right index finger or quadriceps muscle of the right leg. Contralateral forearm and calf blood flows (strain gauge plethysmography) and arterial blood pressure (auscultation) were measured simultaneously. Each exercise caused a decrease in forearm vascular resistance and a progressive increase in calf resistance. These changes were greatest with the 40% MVC. With finger exercise at 20 and 40% MVC, the percentage decreases in forearm vascular resistance from control were 12.3 and 22.7%, respectively (P less than 0.01). Similar decreases (9.5 and 24.9%, respectively; P less than 0.01) were noted with exercise of the quadriceps muscle. By contrast, the corresponding increases in calf vascular resistance were greater (P less than 0.01) with quadriceps exercise (13.3 and 55.4%, respectively) than with finger exercise (6.0 and 36.0%). Arrest of the circulation to the exercising muscles just before the exercise ended caused an abrupt increase in forearm vascular resistance and a decrease in calf resistance. These studies provide further evidence of the heterogeneity of responses of forearm and calf resistance vessels to certain cardiovascular stimuli.

Simultaneous measurements were made of changes in vascular resistance in the forearm and calf in response to moving from supine to sitting or to head-down tilt. The subjects were healthy male volunteers, 21–63 yr. Blood flows were measured by venous occlusion plethysmography using mercury-in-Silastic strain-gauges. The gauges were maintained at the same level relative to the heart during the postural changes. Arterial blood pressure was measured by auscultation; heart rate was counted from the plethysmograms. Changing from supine to sitting caused a decrease in forearm blood flow from 4.13 +/- 0.14 to 2.16 +/- 0.19 ml.100 ml-1.min-1. Corresponding calf flows were 4.21 +/- 0.32 and 4.40 +/- 0.59 ml.100 ml-1.min-1. There was no change in mean arterial blood pressure, and heart rate increased by 8.0 +/- 1.5 beats/min. Arrest of the circulation of both legs with occlusion cuffs on the thighs before sitting, to prevent pooling of blood in them, reduced the degree of forearm vasoconstriction. Neck suction (40 Torr) during sitting, to oppose the decrease in transmural pressure at the carotid sinuses, inhibited the vasoconstriction. During a 30 degrees head-down tilt, there was a dilatation of forearm but not of calf resistance vessels. A Valsalva maneuver caused a similar constriction of both vascular beds. Thus, when changes in vascular resistance in forearm and calf are compared, the major reflex adjustments to changes in posture take place in the forearm.

Background HIV infection leads to activation of coagulation, which may increase the risk for atherosclerosis and venous thromboembolic disease. We hypothesized that HIV replication increases coagulation potentially through alterations in extrinsic pathway factors. Methods and Results Extrinsic pathway factors were measured among a subset of HIV participants from the Strategies for Management of Anti‐Retroviral Therapy ( SMART ) trial. Thrombin generation was estimated using validated computational modeling based on factor composition. We characterized the effect of antiretroviral therapy ( ART ) treatment versus the untreated state ( HIV replication) via 3 separate analyses: (1) a cross‐sectional comparison of those on and off ART (n=717); (2) a randomized comparison of deferring versus starting ART (n=217); and (3) a randomized comparison of stopping versus continuing ART (n=500). Compared with viral suppression, HIV replication consistently showed short‐term increases in some procoagulants (eg, 15% to 23% higher FVIII ; P <0.001) and decreases in key anticoagulants (eg, 5% to 9% lower antithrombin [ AT ] and 6% to 10% lower protein C; P <0.01). The net effect of HIV replication was to increase coagulation potential (eg, 24% to 48% greater thrombin generation from computational models; P <0.01 for all). The pattern of changes from HIV replication was reversed with ART treatment and consistent across all 3 independent comparisons. Conclusions HIV replication leads to complex changes in extrinsic pathway factors, with the net effect of increasing coagulation potential to a degree that may be clinically relevant. The key influence of changes in FVIII and AT suggests that HIV ‐related coagulation abnormalities may involve changes in hepatocyte function in the context of systemic inflammation. Clinical Trial Registration URL: ClinicalTrials.gov . Unique identifier: NCT 00027352.

AbstractBACKGROUNDSoluble intercellular adhesion molecule 1 (sICAM-1) is associated with endothelial dysfunction and clinical cardiovascular disease. We investigated the relationship of subclinical atherosclerosis with sICAM-1 concentration.METHODSsICAM-1 concentration was assayed at year 15 of the Coronary Artery Risk Development in Young Adults (CARDIA) Study (black and white men and women, average age 40 years). We assessed progression of coronary artery calcification (CAC) through year 20 (n = 2378), and both carotid artery stenosis (n = 2432) and intima-media thickness (IMT) at year 20 (n = 2240).RESULTSMedian sICAM-1 was 145.9 μg/L. Among a subgroup with advanced atherosclerotic plaque (either CAC or stenosis), IMT was 0.010 (95% CI 0.003–0.017 mm) higher per SD of sICAM-1 (44 μg/L) in a model adjusted for age, race, sex, clinic, smoking, exercise, body size, education, blood pressure, antihypertensive medication, plasma lipids, and cholesterol-lowering medication. With the same adjustment, the odds ratio (OR) for the presence of year-20 carotid artery stenosis per SD of sICAM-1 was 1.12 (95% CI 1.01–1.25, P &lt; 0.04), whereas for occurrence of CAC progression the OR was 1.16 (1.04–1.31, P &lt; 0.01). The associations with CAC and carotid stenosis were strongest in the top 20th of the sICAM-1 distribution.CONCLUSIONSsICAM-1 concentration may be an early biomarker that indicates changes in the artery wall that accompany atherosclerosis, as well as the presence of advanced plaque in the coronary and carotid arteries. This finding holds in people with low total burden of atherosclerosis, decades before the development of clinical CVD.