Association Between Acute Exposure to Crime and Individual Systolic Blood Pressure.

INTRODUCTION: Hypertension is associated with adverse cardiovascular outcomes and is geographically concentrated in urban underserved neighborhoods. This study examines the temporal-spatial association between individual exposure to violent crime and blood pressure. METHODS: A retrospective observational cohort study analyzed 39,211 patients with 227,595 blood pressure measurements from 2014 to 2016 at 3 outpatient clinics at an academic medical center in Chicago. Patients were included in the study if they had documentation of blood pressure in the medical record and resided in census tracts with >1,000 observations. Geocoded violent crime events were obtained from the Chicago Police Department. Individual-level exposure was defined on the basis of spatial and temporal buffers around each patient's home. Spatial buffers included 100-, 250-, 500-, and 1,000-meter disc radii, and temporal buffers included 7, 30, and 60 days preceding each outpatient appointment. Systolic blood pressure measurements (mmHg) were abstracted from the electronic health record. Analysis was performed in 2019-2020. RESULTS: For each violent crime event within 100 meters from home, systolic blood pressure increased by 0.14 mmHg within 7 days of exposure compared with 0.08 mmHg at 30 days of exposure. In analyses stratified by neighborhood cluster, systolic blood pressure increased by 0.37 mmHg among patients in the suburban affluent cluster relative to that among those in an extreme poverty cluster for the same spatial and temporal buffer. CONCLUSIONS: Exposure to a violent crime event was associated with increased blood pressure, with gradient effects by both distance and time from exposure.

A retrospective analysis of high sensitivity cardiac troponin-T ranges in non-myocardial infarction emergency department visits.

INTRODUCTION: Current evidence suggests that high sensitivity cardiac troponin-T (hs-cTnT) values differ based on sex, race, age, and kidney function. However, most studies examining the relationship of hs-cTnT and these individual factors are in healthy participants, leading to difficulty in interpreting hs-cTnT values in the Emergency Department (ED) setting. We seek to examine the relationship between hs-cTnT values and sex, race, age, and kidney function in a contemporary, urban academic setting. METHODS: ED visits from June 2018 through April 2019 with at least 1 hs-cTnT and no diagnosis of acute myocardial infarction (AMI) at an academic medical center in the south side of Chicago were retrospectively analyzed. Median hs-cTnT values were stratified by sex (male or female), race (African American or Caucasian), age, estimated glomerular filtration rate (eGFR), and stage of chronic kidney disease. RESULTS: 9679 encounters, representing 7989 distinct patients, were included for analysis (age 58 ± 18 years, 59% female, 85% black). Males had significantly higher median hs-cTnT values than females (16 [8-34] vs. 9 [6-22] ng/L, p < 0.001), African Americans had a significantly lower median value than Caucasians (10 [6-24] vs. 15 [6-29] ng/L, p < 0.001), and those with atrial fibrillation (27 [16-48] vs. 9 [6-19] ng/L, p < 0.001) and heart failure (28 [14-48] vs. 8 [6-15] ng/L, p < 0.001) had higher median values than those without. Median hs-cTnT values increased significantly with increased age and decreased eGFR. All relationships continued to be significant even after multivariable regression of sex, age, race, eGFR, presence of atrial fibrillation, and presence of heart failure (p < 0.01). CONCLUSIONS: Analysis of hs-cTnT in non-AMI patients during ED encounters showed that males have higher values than females, African Americans have lower values than Caucasians, those with atrial fibrillation and heart failure have higher values than those without, and that older age and lower eGFR were associated with higher median values.

Social determinants of health and hospital readmissions: can the HOSPITAL risk score be improved by the inclusion of social factors?

BACKGROUND: The HOSPITAL Risk Score (HRS) predicts 30-day hospital readmissions and is internationally validated. Social determinants of health (SDOH) such as low socioeconomic status (SES) affect health outcomes and have been postulated to affect readmission rates. We hypothesized that adding SDOH to the HRS could improve its predictive accuracy. METHODS: Records of 37,105 inpatient admissions at the University of Chicago Medical Center were reviewed. HRS was calculated for each patient. Census tract-level SDOH then were combined with the HRS and the performance of the resultant "Social HRS" was compared against the HRS. Patients then were assigned to 1 of 7 typologies defined by their SDOH and a balanced dataset of 14,235 admissions was sampled from the larger dataset to avoid over-representation by any 1 sociodemographic group. Principal component analysis and multivariable linear regression then were performed to determine the effect of SDOH on the HRS. RESULTS: The c-statistic for the HRS predicting 30-day readmission was 0.74, consistent with published values. However, the addition of SDOH to the HRS did not improve the c-statistic (0.71). Patients with unfavorable SDOH (no high-school, limited English, crowded housing, disabilities, and age > 65 yrs) had significantly higher HRS (p < 0.05 for all). Overall, SDOH explained 0.2% of the HRS. CONCLUSION: At an urban tertiary care center, the addition of census tract-level SDOH to the HRS did not improve its predictive power. Rather, the effects of SDOH are already reflected in the HRS.

SALAD-BAAR: A numerical risk score for hospital admission or emergency department presentation in ambulatory patients with cardiovascular disease.

BACKGROUND: While many interventions to reduce hospital admissions and emergency department (ED) visits for patients with cardiovascular disease have been developed, identifying ambulatory cardiac patients at high risk for admission can be challenging. HYPOTHESIS: A computational model based on readily accessible clinical data can identify patients at risk for admission. METHODS: Electronic health record (EHR) data from a tertiary referral center were used to generate decision tree and logistic regression models. International Classification of Disease (ICD) codes, labs, admissions, medications, vital signs, and socioenvironmental variables were used to model risk for ED presentation or hospital admission within 90 days following a cardiology clinic visit. Model training and testing were performed with a 70:30 data split. The final model was then prospectively validated. RESULTS: A total of 9326 patients and 46 465 clinic visits were analyzed. A decision tree model using 75 patient characteristics achieved an area under the curve (AUC) of 0.75 and a logistic regression model achieved an AUC of 0.73. A simplified 9-feature model based on logistic regression odds ratios achieved an AUC of 0.72. A further simplified numerical score assigning 1 or 2 points to each variable achieved an AUC of 0.66, specificity of 0.75, and sensitivity of 0.58. Prospectively, this final model maintained its predictive performance (AUC 0.63-0.60). CONCLUSION: Nine patient characteristics from routine EHR data can be used to inform a highly specific model for hospital admission or ED presentation in cardiac patients. This model can be simplified to a risk score that is easily calculated and retains predictive performance.

Community Health Workers Reduce Rehospitalizations and Emergency Department Visits for Low-Socioeconomic Urban Patients With Heart Failure.

BACKGROUND: Low-socioeconomic, urban, minority patients with heart failure (HF) often have unique barriers to care. Community health workers (CHWs) are specially trained laypeople who serve as liaisons between underserved communities and the health system. It is not known whether CHWs improve outcomes in low-socioeconomic, urban, minority patients with HF. HYPOTHESIS: CHWs reduce rehospitalizations, emergency department (ED) visits, and healthcare costs for low-socioeconomic urban patients with HF. METHODS: Patients admitted with acute decompensated HF were assigned to receive weekly visits by CHW after discharge. Patients were propensity score matched with controls who received usual care. HF-related rehospitalizations, ED visits, and inpatient costs were compared for 12 months following index admission versus the same period before. RESULTS: Twenty-eight patients who received weekly visits from a CHW for 12 months after discharge were matched with 28 control patients who did not receive CHWs. Patients who received a CHW had a 75% decrease in HF-related ED visits (0.71 vs. 0.18 visits per patient, P < 0.001), an 89% decrease in HF-related readmissions (0.64 vs. 0.07 admissions per patient, P < 0.005), and a significant decrease in inpatient cost for HF-related visits. In controls receiving usual care, there was no significant change in hospitalizations, ED visits, or costs. CONCLUSIONS: In conclusion, CHWs are associated with reduced rehospitalizations, ED visits, and inpatient costs in low-socioeconomic, urban, minority patients with HF. CHWs may be a cost-effective method to reduce health care utilization and improve outcomes for this population.

Association of Rising Violent Crime With Blood Pressure and Cardiovascular Risk: Longitudinal Evidence From Chicago, 2014-2016.

BACKGROUND: The purpose of this study was to examine the longitudinal association between rising violent crime and elevated blood pressure (BP). METHODS: We analyzed 217,816 BP measurements from 17,783 adults during a temporal surge in violent crime in Chicago (2014-2016). Serial observations were abstracted from the electronic health record at an academic medical center and paired to the City of Chicago Police Data Portal. The violent crime rate (VCR) was calculated as the number of violent crimes per 1,000 population per year for each census tract. Longitudinal multilevel regression models were implemented to assess elevated BP (systolic BP ≥ 140 mm Hg or diastolic BP ≥ 90 mm Hg) as a function of the VCR, adjusting for patient characteristics, neighborhood characteristics, and time effects. Secondary dependent measures included elevated heart rate, obesity, missed outpatient appointments, all-cause hospital admissions, and cardiovascular hospital admissions. RESULTS: At baseline, the median VCR was 41.3 (interquartile range: 15.2-66.8), with a maximum rise in VCR of 59.1 over the 3-year surge period. A 20-unit rise in the VCR was associated with 3% higher adjusted odds of having elevated BP (95% confidence interval [CI]: 1.01-1.06), 8% higher adjusted odds of missing an outpatient appointment (95% CI: 1.03-1.13), and 6% higher adjusted odds of having a cardiovascular-related hospital admission (95% CI: 1.01-1.12); associations were not significant for elevated heart rate and obesity. CONCLUSION: Rising violent crime was associated with increased BP during a temporal crime surge.

Cost-utility of extracorporeal cardiopulmonary resuscitation in patients with cardiac arrest.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) is a resource-intensive tool that provides haemodynamic and respiratory support in patients who have suffered cardiac arrest. In this study, we investigated the cost-utility of ECPR (cost/QALY) in cardiac arrest patients treated at our institution. METHODS: We performed a retrospective review of patients who received ECPR following cardiac arrest between 2012 and 2018. All medical care-associated charges with ECPR and subsequent hospital admission were recorded. The quality-of-life of survivors was assessed with the Health Utilities Index Mark II. The cost-utility of ECPR was calculated with cost and quality-of-life data. RESULTS: ECPR was used in 32 patients (15/32 in-hospital, 47%) with a median age of 55.0 years (IQR 46.3-63.3 years), 59% male and 66% African American. The median duration of ECPR support was 2.1 days (IQR 0.9-3.8 days). Survival to hospital discharge was 16%. The median score of the Health Utilities Index Mark II at discharge for the survivors was 0.44 (IQR 0.32-0.52). The median operating cost for patients undergoing ECMO was $125,683 per patient (IQR $49,751-$206,341 per patient). The calculated cost-utility for ECPR was $56,156/QALY gained. CONCLUSIONS: The calculated cost-utility is within the threshold considered cost-effective in the United States (<$150,000/QALY gained). These results are comparable to the cost-effectiveness of heart transplantation for end-stage heart failure. Larger studies are needed to assess the cost-utility of ECPR and to identify whether other factors, such as patient characteristics, affect the cost-utility benefit.

Neuroprotection Mediated by Upregulation of Endothelial Nitric Oxide Synthase in Rho-Associated, Coiled-Coil-Containing Kinase 2 Deficient Mice.

BACKGROUND: Rho-associated kinases (ROCK1 and ROCK2) are important regulators of the actin cytoskeleton and endothelial nitric oxide synthase (eNOS). Because the phosphorylation of eukaryotic elongation factor-1A1 (eEF1A1) by ROCK2 is critical for eNOS expression, we hypothesized that this molecular pathway may play a critical role in neuroprotection following focal cerebral ischemia.Methods and Results:Adult male wild-type (WT) and mutant ROCK2 and eNOS-/-mice were subjected to middle cerebral artery occlusion (MCAO), and cerebral infarct size, neurological deficit and absolute cerebral blood flow were measured. In addition, aortic endothelium-dependent response to acetylcholine, NG-nitro-L-arginine methyl ester (L-NAME) and sodium nitroprusside were assessed ex vivo. Endothelial cells from mouse brain or heart were used to measure eNOS and eEF1A activity, as well as NO production and eNOS mRNA half-life. In global hemizygous ROCK2+/-and endothelial-specific EC-ROCK2-/-mice, eNOS mRNA stability and eNOS expression were increased, which correlated with enhanced endothelium-dependent relaxation and neuroprotection following focal cerebral ischemia. Indeed, when ROCK2+/-mice were place on an eNOS-/-background, the neuroprotective effects observed in ROCK2+/-mice were abolished. CONCLUSIONS: These findings indicate that the phosphorylation of eEF1A1 by ROCK2 is physiologically important for eNOS expression and NO-mediated neuroprotection, and suggest that targeting endothelial ROCK2 and eEF1A may have therapeutic benefits in ischemic stroke and cardiovascular disease.

A clinical pathway for heart failure reduces admissions from the ED without increasing congestion in the ED.

BACKGROUND: A multidisciplinary team at a major academic medical center established an Acutely Decompensated Heart Failure Clinical Pathway (ADHFCP) program to reduce inpatient readmission rates among patients with heart failure which, among several interventions, included an immediate consultation from a cardiologist familiar with an ADHFCP patient when the patient presented at the Emergency Department (ED). This study analyzed how that program impacted utilization of services in the ED and its subsequent effect on rates of admission from the ED and on disposition times. METHODS: ADHFCP inpatient visits were retrospectively risk stratified and matched with non-program inpatient visits to create a control group. A Cox survival model analyzed the ADHFCP's impact on patients' likelihood to visit the ED. Multivariable ANOVA evaluated the impact of the program on the patients' likelihood of being admitted when presenting at the ED. The ADHFCP's impact on bed-to-disposition time in the ED was evaluated by Wilcoxon's rank-sum test, as were doses of diuretics administered in the ED. RESULTS: The survival analysis showed no impact of the ADHFCP on patients' likelihood of visiting the ED, but ADHFCP patients presenting to the ED were 13.1 (95% CI: 3.6-22.6) percentage points less likely to be admitted. There was no difference in bed-to-disposition times, but ADHFCP patients received diuretics more frequently and at higher doses. CONCLUSIONS: Improved communication between cardiologists and ED physicians through the establishment of an explicit pathway to coordinate the care of heart failure patients may decrease that population's likelihood of admission without increasing ED disposition times.

Tumor necrosis factor-α levels and non-surgical bleeding in continuous-flow left ventricular assist devices.

BACKGROUND: Non-surgical bleeding (NSB) due to angiodysplasia is common in left ventricular assist device (LVAD) patients. Thrombin-induced angiopoietin-2 (Ang-2) expression in LVAD patients leads to altered angiogenesis and is associated with lower angiopoietin-1 (Ang-1) and increased NSB. However, the mechanism for decreased Ang-1, made by pericytes, is unknown and the origin of thrombin in LVAD patients is unclear. We hypothesized that high tumor necrosis factor-α (TNF-α) levels in LVAD patients induce pericyte apoptosis, tissue factor (TF) expression and vascular instability. METHODS: We incubated cultured pericytes with serum from patients with heart failure (HF), LVAD or orthotopic heart transplantation (OHT), with or without TNF-α blockade. We performed several measurements: Ang-1 expression was assessed by reverse transcript-polymerase chain reaction (RT-PCR) and pericyte death fluorescently; TF expression was assessed by RT-PCR in cultured endothelial cells incubated with patient plasma with or without TNF-α blockade; and TF expression was assessed in endothelial biopsy samples from these patients by immunofluorescence. We incubated cultured endothelial cells on Matrigel with patient serum with or without TNF-α blockade and determined tube formation by microscopy. RESULTS: Serum from LVAD patients had higher levels of TNF-α, suppressed Ang-1 expression in pericytes, and induced pericyte death, and there was accelerated endothelial tube formation compared with serum from patients without LVADs. TF was higher in both plasma and endothelial cells from LVAD patients, and plasma from LVAD patients induced more endothelial TF expression. All of these effects were reversed or reduced with TNF-α blockade. High levels of TNF-α were associated with increased risk of NSB. CONCLUSIONS: Elevated TNF-α in LVAD patients is a central regulator of altered angiogenesis, pericyte apoptosis and expression of TF and Ang-1.

Cardiology Consultation in the Emergency Department Reduces Re-hospitalizations for Low-Socioeconomic Patients with Acute Decompensated Heart Failure.

BACKGROUND: Re-hospitalization after discharge for acute decompensated heart failure is a common problem. Low-socioeconomic urban patients suffer high rates of re-hospitalization and often over-utilize the emergency department (ED) for their care. We hypothesized that early consultation with a cardiologist in the ED can reduce re-hospitalization and health care costs for low-socioeconomic urban patients with acute decompensated heart failure. METHODS: There were 392 patients treated at our center for acute decompensated heart failure who received standardized education and follow-up. Patients who returned to the ED received early consultation with a cardiologist; 392 patients who received usual care served as controls. Thirty- and 90-day re-hospitalization, ED re-visits, heart failure symptoms, mortality, and health care costs were recorded. RESULTS: Despite guideline-based education and follow-up, the rate of ED re-visits was not different between the groups. However, the rate of re-hospitalization was significantly lower in patients receiving the intervention compared with controls (odds ratio 0.592), driven by a reduction in the risk of readmission from the ED (0.56 vs 0.79, respectively). Patients receiving the intervention accumulated 14% fewer re-hospitalized days than controls and 57% lower 30-day total health care cost. Despite the reduction in health care resource consumption, mortality was unchanged. After accounting for the total cost of intervention delivery, the health care cost savings was substantially greater than the cost of intervention delivery. CONCLUSION: Early consultation with a cardiologist in the ED as an adjunct to guideline-based follow-up is associated with reduced re-hospitalization and health care cost for low-socioeconomic urban patients with acute decompensated heart failure.

Elevated Angiopoietin-2 Level in Patients With Continuous-Flow Left Ventricular Assist Devices Leads to Altered Angiogenesis and Is Associated With Higher Nonsurgical Bleeding.

BACKGROUND: Nonsurgical bleeding is the most common adverse event in patients with continuous-flow left ventricular assist devices (LVADs) and is caused by arteriovenous malformations. We hypothesized that deregulation of an angiogenic factor, angiopoietin-2 (Ang-2), in patients with LVADs leads to increased angiogenesis and higher nonsurgical bleeding. METHODS: Ang-2 and thrombin levels were measured by ELISA and Western blotting, respectively, in blood samples from 101 patients with heart failure, LVAD, or orthotopic heart transplantation. Ang-2 expression in endothelial biopsy was quantified by immunofluorescence. Angiogenesis was determined by in vitro tube formation from serum from each patient with or without Ang-2-blocking antibody. Ang-2 gene expression was measured by reverse transcription-polymerase chain reaction in endothelial cells incubated with plasma from each patient with or without the thrombin receptor blocker vorapaxar. RESULTS: Compared with patients with heart failure or those with orthotopic heart transplantation, serum levels and endothelial expression of Ang-2 were higher in LVAD patients (P=0.001 and P<0.001, respectively). This corresponded to an increased angiogenic potential of serum from patients with LVADs (P<0.001), which was normalized with Ang-2 blockade. Furthermore, plasma from LVAD patients contained higher amounts of thrombin (P=0.003), which was associated with activation of the contact coagulation system. Plasma from LVAD patients induced more Ang-2 gene expression in endothelial cells (P<0.001), which was reduced with thrombin receptor blockade (P=0.013). LVAD patients with Ang-2 levels above the mean (12.32 ng/mL) had more nonsurgical bleeding events compared with patients with Ang-2 levels below the mean (P=0.003). CONCLUSIONS: Our findings indicate that thrombin-induced Ang-2 expression in LVAD patients leads to increased angiogenesis in vitro and may be associated with higher nonsurgical bleeding events. Ang-2 therefore may contribute to arteriovenous malformation formation and subsequent bleeding in LVAD patients.

Intravenous Lipid Infusion Induces Endoplasmic Reticulum Stress in Endothelial Cells and Blood Mononuclear Cells of Healthy Adults.

BACKGROUND: Endoplasmic reticulum (ER) stress and the subsequent unfolded protein response may initially be protective, but when prolonged, have been implicated in atherogenesis in diabetic conditions. Triglycerides and free fatty acids (FFAs) are elevated in patients with diabetes and may contribute to ER stress. We sought to evaluate the effect of acute FFA elevation on ER stress in endothelial and circulating white cells. METHODS AND RESULTS: Twenty-one healthy subjects were treated with intralipid (20%; 45 mL/h) plus heparin (12 U/kg/h) infusion for 5 hours. Along with increased triglyceride and FFA levels, intralipid/heparin infusion reduced the calf reactive hyperemic response without a change in conduit artery flow-mediated dilation consistent with microvascular dysfunction. To investigate the short-term effects of elevated triglycerides and FFA, we measured markers of ER stress in peripheral blood mononuclear cells (PBMCs) and vascular endothelial cells (VECs). In VECs, activating transcription factor 6 (ATF6) and phospho-inositol requiring kinase 1 (pIRE1) proteins were elevated after infusion (both P<0.05). In PBMCs, ATF6 and spliced X-box-binding protein 1 (XBP-1) gene expression increased by 2.0- and 2.5-fold, respectively (both P<0.05), whereas CHOP and GADD34 decreased by ≈67% and 74%, respectively (both P<0.01). ATF6 and pIRE1 protein levels also increased (both P<0.05), and confocal microscopy revealed the nuclear localization of ATF6 after infusion, suggesting activation. CONCLUSIONS: Along with microvascular dysfunction, intralipid infusion induced an early protective ER stress response evidenced by activation of ATF6 and IRE1 in both leukocytes and endothelial cells. Our results suggest a potential link between metabolic disturbances and ER stress that may be relevant to vascular disease.

Sample size and cost analysis for pulmonary arterial hypertension drug trials using various imaging modalities to assess right ventricular size and function end points.

BACKGROUND: Placebo-controlled trials for pulmonary arterial hypertension are no longer acceptable because new therapies must show clinically significant effects on top of standard treatment. The purpose of this study was to estimate sample sizes and imaging costs for the planning of a hypothetical pulmonary arterial hypertension drug trial using imaging to detect changes in right ventricular size and function in response to combined therapy. METHODS AND RESULTS: Same-day cardiovascular MR (CMR) and 2-dimensional (2D) and 3D transthoracic echocardiography (2DTTE and 3DTTE) were performed in 22 patients with pulmonary arterial hypertension (54±13 years of age) twice, 6 months apart. Short-axis CMR cines and full-volume 3DTTE data sets of the right ventricle were used to measure end-diastolic volume and ejection fraction. Fractional area change was obtained from 2DTTE. Sample size calculations used a 2-sample t test model incorporating differences between baseline and 6-month measurements. Cost estimates were made using the Medicare fee schedule. No significant differences were noted between baseline and follow-up measurements. Large SDs reflected variable progression of disease in individual patients on standard therapy and measurement variability. These sources of variability resulted in intertechnique differences in sample sizes: to detect a change of 5% to 15% in 3DTTE-derived right ventricular ejection fraction and fractional area change or change of 15 to 30 mL in 3DTTE right ventricular end-diastolic volume; sample sizes were 2× to 2.5× those required by CMR. As a result, the total cost of a trial using complete TTE was greater than CMR, which was greater than limited TTE. CONCLUSIONS: Because of lower measurement variability, CMR is more cost saving in pulmonary arterial hypertension drug trials than echocardiography, unless limited TTE is used.

Peripheral artery disease is associated with severe impairment of vascular function.

Patients with peripheral artery disease (PAD) have higher cardiovascular event rates than patients with established coronary artery disease (CAD) and abnormal endothelial function predicts cardiovascular risk in PAD and CAD. We investigated the hypothesis that PAD is associated with a greater degree of impairment in vascular function than CAD. We used several non-invasive tests to evaluate endothelial function in 1320 men and women with combined PAD and CAD (n = 198), PAD alone (n = 179), CAD alone (n = 466), or controls aged > 45 years without CAD or PAD (n = 477). Patients with PAD had lower brachial artery flow-mediated dilation (5.1 ± 3.9% PAD and CAD, 5.9 ± 4.4% PAD alone) compared to patients with CAD alone (7.0 ± 4.5%) and no PAD or CAD (8.1 ± 5.1%, p < 0.0001). In multivariable models adjusting for clinical covariates and the presence of CAD, PAD remained associated with lower flow-mediated dilation (p < 0.0001). PAD was associated also with lower nitroglycerin-mediated dilation and reactive hyperemia. Patients with both PAD and CAD had a lower digital pulse amplitude tonometry (PAT) ratio in unadjusted models but not in adjusted models. Flow-mediated dilation was modestly associated with PAT ratio in patients with atherosclerotic disease (r = 0.23, p < 0.0001) but not among control participants (r = 0.008, p = 0.93). Our findings indicate that patients with PAD have greater impairment of vasodilator function and are consistent with the possibility that endothelial dysfunction may contribute to adverse cardiovascular prognosis in PAD.

Protein kinase C-ß contributes to impaired endothelial insulin signaling in humans with diabetes mellitus.

BACKGROUND: Abnormal endothelial function promotes atherosclerotic vascular disease in diabetes. Experimental studies indicate that disruption of endothelial insulin signaling, through the activity of protein kinase C-ß (PKCß) and nuclear factor κB, reduces nitric oxide availability. We sought to establish whether similar mechanisms operate in the endothelium in human diabetes mellitus. METHODS AND RESULTS: We measured protein expression and insulin response in freshly isolated endothelial cells from patients with type 2 diabetes mellitus (n=40) and nondiabetic controls (n=36). Unexpectedly, we observed 1.7-fold higher basal endothelial nitric oxide synthase (eNOS) phosphorylation at serine 1177 in patients with diabetes mellitus (P=0.007) without a difference in total eNOS expression. Insulin stimulation increased eNOS phosphorylation in nondiabetic subjects but not in diabetic patients (P=0.003), consistent with endothelial insulin resistance. Nitrotyrosine levels were higher in diabetic patients, indicating endothelial oxidative stress. PKCß expression was higher in diabetic patients and was associated with lower flow-mediated dilation (r=-0.541, P=0.02). Inhibition of PKCß with LY379196 reduced basal eNOS phosphorylation and improved insulin-mediated eNOS activation in patients with diabetes mellitus. Endothelial nuclear factor κB activation was higher in diabetes mellitus and was reduced with PKCß inhibition. CONCLUSIONS: We provide evidence for the presence of altered eNOS activation, reduced insulin action, and inflammatory activation in the endothelium of patients with diabetes mellitus. Our findings implicate PKCß activity in endothelial insulin resistance.

Effect of sulfasalazine on inflammation and endothelial function in patients with established coronary artery disease.

Inflammation is critical for atherosclerosis development and may be a target for risk-reduction therapy. In experimental studies, activation of the inflammatory regulator, nuclear factor kappa B (NFlB), contributes to endothelial activation and reduced nitric oxide production. We treated patients with coronary artery disease with sulfasalazine, an inhibitor of NFκB, and placebo in a randomized, double-blind, crossover study design. Brachial artery flow-mediated dilation (FMD) and digital vascular function were measured at baseline and after each 6-week treatment period. Of the 53 patients enrolled in the crossover study, 32 (age 60 ± 10, 22% female) completed all the visits, with a high rate of study withdrawal due to gastrointestinal side effects. In a subset of 10 participants, we compared the effects of 4 days of sulfasalazine treatment (n = 5) to no treatment (n = 5) on NFκB-regulated gene expression in peripheral blood mononuclear cells. Tumor necrosis factor α-stimulated expression of CD69 and NFlB subunit p50 was significantly blunted after 4 days of sulfasalazine treatment but not after no treatment. However, FMD and digital vasodilator response did not significantly change from baseline with long-term sulfasalazine treatment. Short-term sulfasalazine inhibited NFlB activity; however, long-term treatment was poorly tolerated and did not improve endothelial function. Our findings suggest that sulfasalazine therapy is not the optimal anti-inflammatory treatment for reversing endothelial dysfunction in cardiovascular disease. Further studies are warranted to investigate the potential for NFlB inhibition to reduce cardiovascular risk.

Altered mitochondrial dynamics contributes to endothelial dysfunction in diabetes mellitus.

BACKGROUND: Endothelial dysfunction contributes to the development of atherosclerosis in patients with diabetes mellitus, but the mechanisms of endothelial dysfunction in this setting are incompletely understood. Recent studies have shown altered mitochondrial dynamics in diabetes mellitus with increased mitochondrial fission and production of reactive oxygen species. We investigated the contribution of altered dynamics to endothelial dysfunction in diabetes mellitus. METHODS AND RESULTS: We observed mitochondrial fragmentation (P=0.002) and increased expression of fission-1 protein (Fis1; P<0.0001) in venous endothelial cells freshly isolated from patients with diabetes mellitus (n=10) compared with healthy control subjects (n=9). In cultured human aortic endothelial cells exposed to 30 mmol/L glucose, we observed a similar loss of mitochondrial networks and increased expression of Fis1 and dynamin-related protein-1 (Drp1), proteins required for mitochondrial fission. Altered mitochondrial dynamics was associated with increased mitochondrial reactive oxygen species production and a marked impairment of agonist-stimulated activation of endothelial nitric oxide synthase and cGMP production. Silencing Fis1 or Drp1 expression with siRNA blunted high glucose-induced alterations in mitochondrial networks, reactive oxygen species production, endothelial nitric oxide synthase activation, and cGMP production. An intracellular reactive oxygen species scavenger provided no additional benefit, suggesting that increased mitochondrial fission may impair endothelial function via increased reactive oxygen species. CONCLUSION: These findings implicate increased mitochondrial fission as a contributing mechanism for endothelial dysfunction in diabetic states.