Circulating Progenitor Cells Identify Peripheral Arterial Disease in Patients With Coronary Artery Disease.

RATIONALE: Peripheral arterial disease (PAD) is a clinical manifestation of extracoronary atherosclerosis. Despite sharing the same risk factors, only 20% to 30% of patients with coronary artery disease (CAD) develop PAD. Decline in the number of bone marrow-derived circulating progenitor cells (PCs) is thought to contribute to the pathogenesis of atherosclerosis. Whether specific changes in PCs differentiate patients with both PAD and CAD from those with CAD alone is unknown. OBJECTIVE: Determine whether differences exist in PCs counts of CAD patients with and without known PAD. METHODS AND RESULTS: 1497 patients (mean age: 65 years; 62% men) with known CAD were identified in the Emory Cardiovascular Biobank. Presence of PAD (n=308) was determined by history, review of medical records, or imaging and was classified as carotid (53%), lower extremity (41%), upper extremity (3%), and aortic disease (33%). Circulating PCs were enumerated by flow cytometry. Patients with CAD and PAD had significantly lower PC counts compared with those with only CAD. In multivariable analysis, a 50% decrease in cluster of differentiation 34 (CD34+) or CD34+/vascular endothelial growth factor receptor-2 (VEGFR2+) counts was associated with a 31% (P=0.032) and 183% (P=0.002) increase in the odds of having PAD, respectively. CD34+ and CD34+/VEGFR2+ counts significantly improved risk prediction metrics for prevalent PAD. Low CD34+/VEGFR2+ counts were associated with a 1.40-fold (95% confidence interval, 1.03-1.91) and a 1.64-fold (95% confidence interval, 1.07-2.50) increases in the risk of mortality and PAD-related events, respectively. CONCLUSIONS: PAD is associated with low CD34+ and CD34+/VEGFR2+ PC counts. Whether low PC counts are useful in screening for PAD needs to be investigated.

Novel Biomarker of Oxidative Stress Is Associated With Risk of Death in Patients With Coronary Artery Disease.

BACKGROUND: Free radical scavengers have failed to improve patient outcomes, promoting the concept that clinically important oxidative stress may be mediated by alternative mechanisms. We sought to examine the association of emerging aminothiol markers of nonfree radical mediated oxidative stress with clinical outcomes. METHODS AND RESULTS: Plasma levels of reduced (cysteine and glutathione) and oxidized (cystine and glutathione disulphide) aminothiols were quantified by high performance liquid chromatography in 1411 patients undergoing coronary angiography (mean age 63 years, male 66%). All patients were followed for a mean of 4.7 ± 2.1 years for the primary outcome of all-cause death (n=247). Levels of cystine (oxidized) and glutathione (reduced) were associated with risk of death (P<0.001 both) before and after adjustment for covariates. High cystine and low glutathione levels (>+1 SD and <-1 SD, respectively) were associated with higher mortality (adjusted hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.19-2.21; HR, 2.19; 95% CI, 1.50-3.19; respectively) compared with those outside these thresholds. Furthermore, the ratio of cystine/glutathione was also significantly associated with mortality (adjusted HR, 1.92; 95% CI, 1.39-2.64) and was independent of and additive to high-sensitivity C-reactive protein level. Similar associations were found for other outcomes of cardiovascular death and combined death and myocardial infarction. CONCLUSIONS: A high burden of oxidative stress, quantified by the plasma aminothiols, cystine, glutathione, and their ratio, is associated with mortality in patients with coronary artery disease, a finding that is independent of and additive to the inflammatory burden. Importantly, these data support the emerging role of nonfree radical biology in driving clinically important oxidative stress.

Endothelial dysfunction correlates with exaggerated exercise pressor response during whole body maximal exercise in chronic kidney disease.

Chronic kidney disease (CKD) patients have exercise intolerance associated with increased cardiovascular mortality. Previous studies demonstrate that blood pressure (BP) and sympathetic nerve responses to handgrip exercise are exaggerated in CKD. These patients also have decreased nitric oxide (NO) bioavailability and endothelial dysfunction, which could potentially lead to an impaired ability to vasodilate during exercise. We hypothesized that CKD patients have exaggerated BP responses during maximal whole body exercise and that endothelial dysfunction correlates with greater exercise pressor responses in these patients. Brachial artery flow-mediated dilation (FMD) was assessed before maximal treadmill exercise in 56 participants: 38 CKD (56.7 ± 1.2 yr old, 38 men) and 21 controls (52.8 ± 1.8 yr old, 20 men). During maximal treadmill exercise, the slope-of-rise in systolic BP (+10.32 vs. +7.75 mmHg/stage, P < 0.001), mean arterial pressure (+3.50 vs. +2.63 mmHg/stage, P = 0.004), and heart rate (+11.87 vs. +10.69 beats·min-1·stage-1, P = 0.031) was significantly greater in CKD compared with controls. Baseline FMD was significantly lower in CKD (2.76 ± 0.42% vs. 5.84 ± 0.97%, P = 0.008). Lower FMD values were significantly associated with a higher slope-of-rise in systolic BP (+11.05 vs. 8.71 mmHg/stage, P = 0.003) during exercise in CKD, as well as poorer exercise capacity measured as peak oxygen uptake (V̇o2peak; 19.47 ± 1.47 vs. 24.57 ± 1.51 ml·min-1·kg-1, P < 0.001). These findings demonstrate that low FMD in CKD correlates with augmented BP responses during exercise and lower V̇o2peak, suggesting that endothelial dysfunction may contribute to exaggerated exercise pressor responses and poor exercise capacity in CKD patients.

Tetrahydrobiopterin lowers muscle sympathetic nerve activity and improves augmentation index in patients with chronic kidney disease.

Chronic kidney disease (CKD) is characterized by overactivation of the sympathetic nervous system (SNS) that contributes to cardiovascular risk. Decreased nitric oxide (NO) bioavailability is a major factor contributing to SNS overactivity in CKD, since reduced neuronal NO leads to increased central SNS activity. Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthase that increases NO bioavailability in experimental models of CKD. We conducted a randomized, double-blinded, placebo-controlled trial testing the benefits of oral sapropterin dihydrochloride (6R-BH4, a synthetic form of BH4) in CKD. 36 patients with CKD and hypertension were randomized to 12 wk of 1) 200 mg 6R-BH4 twice daily + 1 mg folic acid once daily; vs. 2) placebo + folic acid. The primary endpoint was a change in resting muscle sympathetic nerve activity (MSNA). Secondary endpoints included arterial stiffness using pulse wave velocity (PWV) and augmentation index (AIx), endothelial function using brachial artery flow-mediated dilation and endothelial progenitor cells, endothelium-independent vasodilatation (EID), microalbuminuria, and blood pressure. We observed a significant reduction in MSNA after 12 wk of 6R-BH4 (-7.5 ± 2.1 bursts/min vs. +3.2 ± 1.3 bursts/min; P = 0.003). We also observed a significant improvement in AIx (by -5.8 ± 2.0% vs. +1.8 ± 1.7 in the placebo group, P = 0.007). EID increased significantly (by +2.0 ± 0.59%; P = 0.004) in the 6R-BH4 group, but there was no change in endothelial function. There was a trend toward a reduction in diastolic blood pressure by -4 ± 3 mmHg at 12 wk with 6R-BH4 (P = 0.055). 6R-BH4 treatment may have beneficial effects on SNS activity and central pulse wave reflections in hypertensive patients with CKD.

Effects of storage-aged red blood cell transfusions on endothelial function in hospitalized patients.

BACKGROUND: Clinical and animal studies indicate that transfusions of older stored red blood cells (RBCs) impair clinical outcomes as compared to fresh RBC transfusions. It has been suggested that this effect is due to inhibition of nitric oxide (NO)-mediated vasodilation after transfusion of older RBC units. However, to date this effect has not been identified in human transfusion recipients. STUDY DESIGN AND METHODS: Forty-three hospitalized patients with transfusion orders were randomly assigned to receive either fresh (<14 days) or older stored (>21 days) RBC units. Before transfusion, and at selected time points after the start of transfusion, endothelial function was assessed using noninvasive flow-mediated dilation assays. RESULTS: After transfusion of older RBC units, there was a significant reduction in NO-mediated vasodilation at 24 hours after transfusion (p = 0.045), while fresh RBC transfusions had no effect (p = 0.231). CONCLUSIONS: This study suggests for the first time a significant inhibitory effect of transfused RBC units stored more than 21 days on NO-mediated vasodilation in anemic hospitalized patients. This finding lends further support to the hypothesis that deranged NO signaling mediates adverse clinical effects of older RBC transfusions. Future investigations will be necessary to address possible confounding factors and confirm these results.

Effect of progenitor cell mobilization with granulocyte-macrophage colony-stimulating factor in patients with peripheral artery disease: a randomized clinical trial.

IMPORTANCE: Many patients with peripheral artery disease (PAD) have walking impairment despite therapy. Experimental studies in animals demonstrate improved perfusion in ischemic hind limb after mobilization of bone marrow progenitor cells (PCs), but whether this is effective in patients with PAD is unknown. OBJECTIVE: To investigate whether therapy with granulocyte-macrophage colony-stimulating factor (GM-CSF) improves exercise capacity in patients with intermittent claudication. DESIGN, SETTING, AND PARTICIPANTS: In a phase 2 double-blind, placebo-controlled study, 159 patients (median [SD] age, 64 [8] years; 87% male, 37% with diabetes) with intermittent claudication were enrolled at medical centers affiliated with Emory University in Atlanta, Georgia, between January 2010 and July 2012. INTERVENTIONS: Participants were randomized (1:1) to received 4 weeks of subcutaneous injections of GM-CSF (leukine), 500 µg/day 3 times a week, or placebo. Both groups were encouraged to walk to claudication daily. MAIN OUTCOMES AND MEASURES: The primary outcome was peak treadmill walking time (PWT) at 3 months. Secondary outcomes were PWT at 6 months and changes in circulating PC levels, ankle brachial index (ABI), and walking impairment questionnaire (WIQ) and 36-item Short-Form Health Survey (SF-36) scores. RESULTS: Of the 159 patients randomized, 80 were assigned to the GM-CSF group. The mean (SD) PWT at 3 months increased in the GM-CSF group from 296 (151) seconds to 405 (248) seconds (mean change, 109 seconds [95% CI, 67 to 151]) and in the placebo group from 308 (161) seconds to 376 (182) seconds (change of 56 seconds [95% CI, 14 to 98]), but this difference was not significant (mean difference in change in PWT, 53 seconds [95% CI, -6 to 112], P = .08). At 3 months, compared with placebo, GM-CSF improved the physical functioning subscore of the SF-36 questionnaire by 11.4 (95% CI, 6.7 to 16.1) vs 4.8 (95% CI, -0.1 to 9.6), with a mean difference in change for GM-CSF vs placebo of 7.5 (95% CI, 1.0 to 14.0; P = .03). Similarly, the distance score of the WIQ improved by 12.5 (95% CI, 6.4 to 18.7) vs 4.8 (95% CI, -0.2 to 9.8) with GM-CSF compared with placebo (mean difference in change, 7.9 [95% CI, 0.2 to 15.7], P = .047). There were no significant differences in the ABI, WIQ distance and speed scores, claudication onset time, or mental or physical component scores of the SF-36 between the groups. CONCLUSIONS AND RELEVANCE: Therapy with GM-CSF 3 times a week did not improve treadmill walking performance at the 3-month follow-up. The improvements in some secondary outcomes with GM-CSF suggest that it may warrant further study in patients with claudication. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01041417.

CD34(+) cell infusion after ST elevation myocardial infarction is associated with improved perfusion and is dose dependent.

BACKGROUND: the objective of the study was to determine whether the effects of infarct-related artery (IRA) infusion of autologous bone marrow-derived CD34(+) cells after ST elevation myocardial infarction (STEMI) are dependent on the dose (quantity and mobility) of the cells infused. Beneficial effects of IRA infusion of mononuclear cells after STEMI have been inconsistent, possibly because of differences in timing, cell type, quantity, and mobility of infused cells. METHODS: patients were randomized to bone marrow harvest (n = 16) or control (n = 15). At a median of 8.3 days after coronary stenting for STEMI, CD34(+) cells were infused via the IRA at 3 dose levels (5, 10, and 15 × 10(6)) in cohorts of 5 patients each. Baseline and follow-up imaging and ex vivo CD34(+) cell mobility were performed. RESULTS: Cell harvest and infusion were safe. Quantitative rest hypoperfusion score measured by single-photon emission computed tomography improved at 6 months in the ≥ 10 million cohorts compared with controls (-256 vs +14, P = .02). There was a trend toward improved ejection fraction at 6 months (+4.5%) in the ≥ 10 million cohorts compared with no change in the controls and 5 million cohort (+0.7%). Improved perfusion and infarct size reduction correlated with the quantity and mobility of the infused CD34(+) cells. CONCLUSIONS: the effects of CD34(+) cell IRA infusion during the repair phase after STEMI are dose dependent and, at a threshold dose of 10 million CD34(+) cells, associated with a significant improvement in perfusion that may limit deterioration in cardiac function (IRA infusion of CD34(+) cells in patients with acute myocardial infarction [AMR-01] NCT00313339).

Characterization of mechanical dyssynchrony measured by gated single photon emission computed tomography phase analysis after acute ST-elevation myocardial infarction.

BACKGROUND: Left ventricular dyssynchrony is an adverse consequence of ST-elevation myocardial infarction (STEMI) and bears an unfavorable prognosis. Mechanical dyssynchrony as measured by phase analysis from gated single photon emission computed tomography (GSPECT) correlates well with other imaging methods of assessing dyssynchrony but has not been studied in STEMI. We hypothesized that systolic dyssynchrony as measured by GSPECT would correlate with adverse remodeling after STEMI. METHODS: In 28 subjects suffering STEMI, GSPECT with technetium-99m sestamibi was performed immediately after presentation (day 5) and remotely (6 months). Parameters of left ventricular dyssynchrony (QRS width, histogram bandwidth (HBW) and phase standard deviation (PSD)) were measured from GSPECT using the Emory Cardiac Toolbox. Left ventricular volumes, ejection fraction (LVEF) and infarct size were also assessed. RESULTS: After successful primary percutaneous coronary intervention to the infarct-related artery, subjects had an LVEF of 46.4% ± 11% and a resting perfusion defect of 27.4% ± 16% at baseline. Baseline QRS width was normal (91.5 ± 17.5 ms). Subjects with STEMI had dyssynchrony compared with a cohort of 22 normal subjects (age 57.2 ± 10.6 years, <5% perfusion defect) by both HBW (100.3° ± 70.7° vs 26.5° ± 5.3°, P < .0001) and PSD (35.3° ± 16.9° vs 7.9° ± 2.1°, P < .0001). Baseline HBW correlated with resting perfusion defect size (r = 0.67, P < .001), end-systolic volume (r = 0.72, P < .001), end-diastolic volume (r = 0.63, P = .001), and inversely with LVEF (r = -0.74, P < .001). HBW and PSD improved over the follow-up period (-24.1 ± 35.9 degrees, P = .003 and -8.7° ± 14.6°, P = .006, respectively), and improvement in HBW correlated with reduction in LV end-systolic volumes (r = 0.43, P = .034). Baseline HBW and PSD, however, did not independently predict LVEF at 6 months follow-up. CONCLUSIONS: After STEMI, subjects exhibit mechanical dyssynchrony as measured by GSPECT phase analysis without evidence of electrical dyssynchrony. Improvement in mechanical dyssynchrony correlates with beneficial ventricular remodeling. The full predictive value of this measure in post-infarct patients warrants further study.

Ethnic differences in subclinical vascular function in South Asians, Whites, and African Americans in the United States.

BACKGROUND: South Asians are a high-risk ethnic group for cardiovascular disease despite having lower levels of conventional cardiovascular risk factors such as obesity and smoking. Ethnic differences in pulse wave reflections, arterial stiffness, and subclinical atherosclerosis as measured using augmentation index (AIX), pulse wave velocity (PWV), and carotid intima-media thickness (CIMT) may reflect some of this excess risk. METHODS: We conducted a cross-sectional analysis of pooled data from three community-based sources in Atlanta, Georgia, USA. Data on 530 South Asians collected from local health fairs was compared with data on 507 White and 192 African Americans from the Emory Predictive Health Initiative and 351 White and 382 African Americans from the Morehouse and Emory Team up to Eliminate Health Disparities Study. RESULTS: Linear regression models adjusted for age, sex, smoking, MAP, fasting glucose, TC, HDL-C, creatinine, and body mass index were used to assess the relationship between ethnicity and vascular function measures. In fully adjusted models, South Asians had higher heart rate corrected AIX as compared with Whites and African Americans (by 5.47%, p < 0.01 and 3.50%, p < 0.01; respectively), but lower PWV (by 0.51 m/s, p < 0.01 and 0.72 m/s, p < 0.01; respectively) and lower CIMT (by 0.02 mm p = 0.03 and 0.04 mm p < 0.01; respectively). CONCLUSIONS: Systemic pulse wave reflections, independent of other risk factors, are higher in South Asians as compared with Whites and African Americans. Future research is needed to determine whether higher AIX explains the increased cardiovascular risk among South Asians.

Pilot randomized controlled trial of a Mediterranean diet or diet supplemented with fish oil, walnuts, and grape juice in overweight or obese US adults.

BACKGROUND: The 2015-2020 Dietary Guidelines for Americans recommend a Mediterranean-type diet as one of three healthful eating patterns. However, only one previous trial has evaluated the effects of a Mediterranean diet intervention in a US sample population. METHODS: To address this gap, we conducted a pilot, non-blinded, 8-week randomized controlled trial on the comparative efficacy of consumption of a Mediterranean diet or a diet supplemented with fish oil, walnuts, and grape juice versus controls. Participants (overweight or obese US adults; 73% female and mean age 51 years) were randomly assigned to one of three groups: (1) Mediterranean diet; (2) habitual high-fat American-type diet supplemented with fish oil, walnuts, and grape juice; or (3) habitual high-fat American-type diet (controls). Intent-to-treat analysis of within-subject differences (Student's paired t-test or Wilcoxon sign ranks test) and between-subject differences (mixed-effects models with a group-by-time interaction term, adjusted for baseline health outcome) was conducted. RESULTS: Participants in the Mediterranean diet arm (n = 11) had significantly greater weight loss despite no significant change in total caloric intake, and lower plasma cystine, indicative of decreased oxidative stress, compared to controls (n = 9) at both 4 and 8 weeks. Compared to controls, they also had significantly lower total cholesterol and low-density lipoprotein cholesterol levels at 4 weeks. Participants in the supplement arm (n = 10) had significantly lower adiponectin levels compared to controls at 4 weeks. No significant improvements in endothelial function or inflammatory biomarkers were observed in either intervention group compared to controls. CONCLUSION: These results suggest that adopting a dietary pattern reflecting a Mediterranean diet improves weight and cardio-metabolic health among overweight or obese US adults, and may be more beneficial than supplementing habitual American diets with fish oil, walnuts, and grape juice.

Comparisons of the Framingham and Pooled Cohort Equation Risk Scores for Detecting Subclinical Vascular Disease in Blacks Versus Whites.

The pooled cohort Atherosclerotic Cardiovascular Disease (ASCVD) risk calculator is designed to improve cardiovascular risk estimation compared with the Framingham Risk Score, particularly in blacks. Although the ASCVD risk score better predicts mortality and incident cardiovascular disease in blacks, less is known about its performance for subclinical vascular disease measures, including arterial stiffness and carotid intima-media thickness. We sought to determine if the ASCVD risk score better identifies subclinical vascular disease in blacks compared with the Framingham risk score. We calculated both the Framingham and ASCVD cohort risk scores in 1,231 subjects (mean age 53 years, 59% female, 37% black) without known cardiovascular disease and measured the extent of arterial stiffness, as determined by pulse wave velocity (PWV), central pulse pressure (CPP), and central augmentation index (CAIx), and subclinical atherosclerosis, as determined by carotid-IMT (C-IMT). Compared with whites, blacks had higher CAIx (23.9 ± 10.2 vs 22.1 ± 9.6%, p = 0.004), CPP (36.4 ± 10.5 vs 34.9 ± 9.8 mmHg, p = 0.014), PWV (7.6 ± 1.5 vs 7.3 ± 1.3 m/s, p = 0.004), and C-IMT (0.67 ± 0.10 vs 0.65 ± 0.10 mm, p = 0.005). In a multivariable analysis including race and Framingham risk score, race remained an independent predictor of all measures of subclinical vascular disease; however, models with race and the ASCVD risk score showed that race was not an independent predictor of subclinical vascular disease. In conclusion, greater subclinical vascular disease in blacks was not estimated by the Framingham risk score. The new ASCVD risk score provided a better estimate of racial differences in vascular function and structure.

Temporal Changes in Cardiovascular Remodeling Associated with Football Participation.

PURPOSE: American-style football (ASF) participation rates in the United States are highest among high school (HS) athletes. This study sought to compare the cardiovascular response to HS versus collegiate ASF participation. METHODS: The ASF participants (HS, n = 61; collegiate, n = 87) were studied at preseason and postseason time points with echocardiography and applanation tonometry. Primary outcome variables included: left ventricular (LV) mass index, LV diastolic function (early relaxation velocity [E']), and arterial stiffness (pulse wave velocity [PWV]). RESULTS: High school (17.1 ± 0.4 yr) and collegiate ASF participants (18 ± 0.4 yr) experienced similar LV hypertrophy (ΔLV mass HS = 10.5 ± 10 vs collegiate = 11.2 ± 13.6 g·m, P = 0.97). Among HS participants, increases in LV mass were associated with stable diastolic tissue velocities (ΔE' = -0.3 ± 2.9 cm·s, P = 0.40) and vascular function (ΔPWV = -0.1 ± 0.6 m·s, P = 0.13). In contrast, collegiate participants demonstrated a higher burden of concentric LV hypertrophy (21/87, 24% vs 7/61, 11%, P = 0.026) with concomitant reductions in diastolic tissue velocities (ΔE': -2.0 ± 2.7 cm·s, P < 0.001) and increased arterial stiffness (ΔPWV: Δ0.2 ± 0.6 m·s, P = 0.003), changes that were influenced by linemen who had the highest post-season weight (124 ± 10 kg) and systolic blood pressure ([SBP], 138.8 ± 11 mm Hg). In multivariable analyses adjusting for age and ethnicity, body mass was an independent predictor of post-season PWV (ß estimate = 0.01, P = 0.04) and E' (ß estimate = -0.04, P = 0.05), whereas SBP was an independent predictor of postseason LV mass index (ß estimate = 0.18, P = 0.01) and PWV (ß estimate = 0.01, P = 0.007). CONCLUSIONS: The transition from HS to college represents an important physiologic temporal data point after which differential ASF cardiovascular phenotypes manifest. Future work aimed to clarify underlying mechanisms, and the long-term clinical implications of these findings is warranted.

Changes in truncal obesity and fat distribution predict arterial health.

BACKGROUND: Truncal obesity is associated with metabolic syndrome and cardiovascular risk. Although vascular health is influenced by weight, it is not known whether changes in fat distribution modulate arterial function. OBJECTIVE: We assessed how changes in truncal (android) fat at 1 year affect arterial stiffness and endothelial function. METHODS: We recruited 711 healthy volunteers (235 males, age 48 ± 11 years) into the Emory Predictive Health Study; 498 returned at 1 year. Measurements included anthropometric and chemistry panels, fat mass using dual-energy X-ray absorptiometry, arterial stiffness indices (pulse wave velocity [PWV], augmentation index [AIx], and subendocardial viability ratio [SEVR]; Sphygmocor), flow-mediated dilation (FMD), and reactive hyperemia index (Endo-PAT). RESULTS: At baseline, measures of body mass correlated with PWV, AIx, SEVR, and FMD. In a multivariable analysis including body mass index (BMI) and traditional risk factors, BMI remained an independent predictor of PWV, AIx, SEVR, and FMD. In a model including BMI and measures of fat distribution, android fat remained an independent predictor of PWV (ß = 0.31, P = .004), AIx (ß = 0.24, P = .008), and SEVR (ß = -0.41, P < .001). The 1-year change in android fat correlated negatively with change in SEVR (ß = -0.13, P = .005) and FMD (ß = -0.13, P = .006) after adjustment for change in gynoid fat. CONCLUSION: In addition to BMI, android fat is a determinant of arterial stiffness, independent of traditional risk factors. Changes in android fat over time are associated with simultaneous changes in vascular function, indicating fat distribution's effect on vascular health.

Sleep-Disordered Breathing and Cardiovascular Correlates in College Football Players.

This study sought to determine the cardiovascular physiologic correlates of sleep-disordered breathing (SDB) in American-style football (ASF) participants using echocardiography, vascular applanation tonometry, and peripheral arterial tonometry. Forty collegiate ASF participants were analyzed at pre- and postseason time points with echocardiography and vascular applanation tonometry. WatchPAT (inclusive of peripheral arterial tonometry) used to assess for SDB was then performed at the postseason time point. Twenty-two of 40 (55%) ASF participants demonstrated SDB with an apnea-hypopnea index (pAHI) ≥5. ASF participants with SDB were larger (109 ± 20 vs 92 ± 14 kg, p = 0.004) and more likely linemen position players (83% vs 50%, p = 0.03). Compared with those without SDB, ASF participants with SDB demonstrated relative impairments in left ventricular diastolic and vascular function as reflected by lower lateral e' (14 ± 3 vs 17 ± 3 cm/s, p = 0.007) and septal e' (11 ± 2 vs 13 ± 2 cm/s, p = 0.009) tissue velocities and higher pulse wave velocity (5.4 ± 0.9 vs 4.8 ± 0.5 m/s, p = 0.02). In the total cohort, there were significant positive correlations between pAHI and pulse wave velocity (r = 0.42, p = 0.008) and inverse correlations between pAHI and the averaged e' tissue velocities (r = -0.42, p = 0.01). In conclusion, SDB is highly prevalent in youthful collegiate ASF participants and associated with relative impairments in cardiac and vascular function. Targeted efforts to identify youthful populations with SDB, including ASF participants, and implement SDB treatment algorithms, represent important future clinical directives.

A novel method of modifying immune responses by vaccination with lipiodol-siRNA mixtures.

The dendritic cell (DC) possesses the ability to stimulate both T helper 1 (Th1) and Th2 responses depending on activation stimuli. Although it is known that chemically or genetically modified DC can be used therapeutically to steer immune responses towards either Th1 or Th2, cellular therapy with ex vivo manipulated DC is clinically difficult. Here we demonstrate a novel method of switching immune responses from Th1 to Th2 through in vivo immune modulation by administration of siRNA. We demonstrate that siRNA targeting of the IL-12p35 gene leads to a Th2 bias in vitro through an IL-10 dependent mechanism. In vivo administration of siRNA admixed with the oil-based contrast agent lipiodol in the presence of antigen and adjuvant induced a deviation in recall response to reduced production of IFN-gamma and augmented IL-4 response using either KLH or ovalbumin. This simple method of in vivo modification of immune response possesses therapeutic potential in Th1-mediated diseases such as multiple sclerosis and autoimmune diabetes.

Induction of antitumor immunity through xenoplacental immunization.

Historically cancer vaccines have yielded suboptimal clinical results. We have developed a novel strategy for eliciting antitumor immunity based upon homology between neoplastic tissue and the developing placenta. Placenta formation shares several key processes with neoplasia, namely: angiogenesis, activation of matrix metalloproteases, and active suppression of immune function. Immune responses against xenoantigens are well known to break self-tolerance. Utilizing xenogeneic placental protein extracts as a vaccine, we have successfully induced anti-tumor immunity against B16 melanoma in C57/BL6 mice, whereas control xenogeneic extracts and B16 tumor extracts where ineffective, or actually promoted tumor growth, respectively. Furthermore, dendritic cells were able to prime tumor immunity when pulsed with the placental xenoantigens. While vaccination-induced tumor regression was abolished in mice depleted of CD4 T cells, both CD4 and CD8 cells were needed to adoptively transfer immunity to naïve mice. Supporting the role of CD8 cells in controlling tumor growth are findings that only freshly isolated CD8 cells from immunized mice were capable of inducing tumor cell caspases-3 activation ex vivo. These data suggest feasibility of using xenogeneic placental preparations as a multivalent vaccine potently targeting not just tumor antigens, but processes that are essential for tumor maintenance of malignant potential.

Low testosterone in men predicts impaired arterial elasticity and microvascular function.

BACKGROUND: A low testosterone level in men is associated with increased adiposity, insulin resistance, and dyslipidemia. Whether low testosterone level is associated with arterial stiffness and endothelial and microvascular dysfunction remains unknown and was investigated in this study. METHODS: Serum testosterone was measured in 237 healthy men aged 50 years (SD 12). Endothelial and microvascular function were assessed as brachial artery flow-mediated dilation (FMD) and digital reactive hyperemia index (RHI), respectively. Arterial stiffness was evaluated by tonometry-derived pulse wave velocity (PWV) and central augmentation index (AIX). RESULTS: Mean total testosterone level was 16.3 nmol/L (SD 6.11) and 25% of subjects had low levels (<12.0 nmol/L). Testosterone level correlated positively with RHI (r=0.24, p<0.001) and inversely with AIX (r=-0.14, p=0.033) but not with FMD or PWV, indicating impaired microvascular hyperemia and arterial elasticity with lower testosterone levels. After multivariate adjustment for the Framingham Risk Score and weight, testosterone level remained an independent predictor of RHI and AIX (ß=0.23, -0.13; p=0.001, 0.04, respectively). CONCLUSION: In men with few co-morbidities, lower serum testosterone level is associated with microvascular dysfunction and increased pulse wave reflections, mechanisms by which lower testosterone levels may confer increased cardiovascular risk. Whether normalization of low testosterone level improves vascular function needs further investigation.

Impact of American-style football participation on vascular function.

Although hypertension is common in American-style football (ASF) players, the presence of concomitant vascular dysfunction has not been previously characterized. We sought to examine the impact of ASF participation on arterial stiffness and to compare metrics of arterial function between collegiate ASF participants and nonathletic collegiate controls. Newly matriculated collegiate athletes were studied longitudinally during a single season of ASF participation and were then compared with healthy undergraduate controls. Arterial stiffness was characterized using applanation tonometry (SphygmoCor). ASF participants (n = 32, 18.4 ± 0.5 years) were evenly comprised of Caucasians (n = 14, 44%) and African-Americans (n = 18, 56%). A single season of ASF participation led to an increase in central aortic pulse pressure (27 ± 4 vs 34 ± 8 mm Hg, p <0.001). Relative to controls (n = 47), pulse wave velocity was increased in ASF participants (5.6 ± 0.7 vs 6.2 ± 0.9 m/s, p = 0.002). After adjusting for height, weight, body mass index, systolic blood pressure, and diastolic blood pressure, ASF participation was independently predictive of increased pulse wave velocity (ß = 0.33, p = 0.04). In conclusion, ASF participation leads to changes in central hemodynamics and increased arterial stiffness.