Faculty Bibliography

Background/UNASSIGNED:Multiple studies demonstrate the benefit of a vegan diet on cardiovascular risk factors when compared to no intervention or usual dietary patterns. The aim of this study is to evaluate the effect of a vegan diet versus the American Heart Association (AHA)-recommended diet on inflammatory and glucometabolic profiles in patients with angiographically defined coronary artery disease (CAD). Study Design/UNASSIGNED:This study is a randomized, open label, blinded end-point trial of 100 patients with CAD as defined by ≥50% diameter stenosis in a coronary artery ≥2 mm in diameter on invasive angiography. Participants are randomized to 8 weeks of either a vegan or AHA-recommended diet (March 2014 and February 2017). Participants are provided weekly groceries that adhere to the guidelines of their diet. The primary endpoint is high sensitivity C-reactive concentrations. Secondary endpoints include anthropometric data, other markers of inflammation, lipid parameters, glycemic markers, endothelial function, quality of life data, and assessment of physical activity. Endpoints are measured at each visit (baseline, 4 weeks, and 8 weeks). Dietary adherence is measured by two weekly 24-hour dietary recalls, a 4-day food record during the week prior to each visit, and both plasma and urine levels of trimethylamine-N-oxide at each visit. Conclusion/UNASSIGNED:This study is the first to comprehensively assess multiple indices of inflammation and glucometabolic profile in a rigorously conducted randomized trial of patients with CAD on a vegan versus AHA-recommended diet.

Type 2 diabetes mellitus (T2D) is a major risk factor for cardiovascular disease (CVD), the most common cause of death in T2D. Yet, <50% of U.S. adults with T2D meet recommended guidelines for CVD prevention. The burden of T2D is increasing: by 2050, approximately 1 in 3 U.S. individuals may have T2D, and patients with T2D will comprise an increasingly large proportion of the CVD population. The authors believe it is imperative that we expand the use of therapies proven to reduce CVD risk in patients with T2D. The authors summarize evidence and guidelines for lifestyle (exercise, nutrition, and weight management) and CVD risk factor (blood pressure, cholesterol and blood lipids, glycemic control, and the use of aspirin) management for the prevention of CVD among patients with T2D. The authors believe appropriate lifestyle and CVD risk factor management has the potential to significantly reduce the burden of CVD among patients with T2D.

OBJECTIVE: Systemic lupus erythematosus (SLE) is associated with the premature development of cardiovascular disease. The platelet-endothelium interaction is important in the pathogenesis of cardiovascular disease. In this study, we investigated the platelet phenotype from patients with SLE and matched controls, and their effect on endothelial cells. APPROACH AND RESULTS: Platelet aggregability was measured in 54 SLE subjects off antiplatelet therapy (mean age 40.1+/-12.8 years; 82% female; 37% white) with age- and sex-matched controls. Platelets were coincubated with human umbilical vein endothelial cells (HUVECs) and changes to gene expression assessed by an RNA array and quantitative reverse transcription polymerase chain reaction. SLE disease activity index ranged from 0 to 22 (mean 5.1+/-3.9). Compared with controls, patients with SLE had significantly increased monocyte and leukocyte-platelet aggregation and platelet aggregation in response to submaximal agonist stimulation. An agnostic microarray of HUVECs cocultured with SLE platelets found a platelet-mediated effect on endothelial gene pathways involved in cell activation. Sera from SLE versus control subjects significantly increased (1) activation of control platelets; (2) platelet adhesion to HUVECs; (3) platelet-induced HUVEC gene expression of interleukin-8, and ICAM-1; and (4) proinflammatory gene expression in HUVECs, mediated by interleukin-1beta-dependent pathway. Incubation of SLE-activated platelets with an interleukin-1beta-neutralizing antibody or HUVECs pretreated with interleukin-1 receptor antibodies attenuated the platelet-mediated activation of endothelial cells. CONCLUSIONS: Platelet activity measurements and subsequent interleukin-1beta-dependent activation of the endothelium are increased in subjects with SLE. Platelet-endothelial interactions may play a role in the pathogenesis of cardiovascular disease in patients with SLE.

OBJECTIVE: Low to moderate inorganic arsenic (iAs) exposure is independently associated with cardiovascular disease (CVD), particularly for patients with diabetes mellitus (DM). The mechanism of increased CVD risk from iAs exposure in DM has not been adequately characterized. We evaluated whether increasing concentrations of glucose enhance the effects of iAs on platelet and megakaryocyte activity, key steps in atherothrombosis. METHODS: Healthy donor whole blood was prepared in a standard fashion and incubated with sodium arsenite in a range from 0 to 10 microM. iAs-induced platelet activation was assessed by platelet receptor CD62P (P-selectin) expression and monocyte-platelet and leukocyte-platelet aggregation (MPA and LPA, respectively) in the presence of increasing sodium arsenite and glucose concentrations. Megakaryocyte (Meg-01) cell adhesion and gene expression was assessed after incubation with or without iAs and increasing concentrations of D-glucose. RESULTS: Platelet activity markers increased significantly with 10 vs. 0 microM iAs (P < 0.05 for all) and with higher D-glucose concentrations. Platelet activity increased significantly following co incubation of 1 and 5 microM iAs concentrations with hyperglycemic D-glucose (P < 0.01 for both) but not after incubation with euglycemic D-glucose. Megakaryocyte adhesion was more pronounced after co incubation with iAs and hyperglycemic than euglycemic D-glucose, while gene expression increased significantly to iAs only after co incubation with hyperglycemic D-glucose. CONCLUSION: We demonstrate that glucose concentrations common in DM potentiate the effect of inorganic arsenic exposure on markers of platelet and megakaryocyte activity. Our results support recent observational cohort data that DM enhances the vasculotoxic effects of arsenic exposure, and suggest that activation of the platelet-megakaryocyte hemostatic axis is a pathway through which inorganic arsenic confers atherothrombotic risk, particularly for patients with DM.

Diabetes mellitus (diabetes) is associated with significantly increased risk of peripheral vascular disease. Diabetes is classified as a coronary heart disease (CHD) risk equivalent, but it is unknown whether diabetes is a CHD risk equivalent for peripheral vascular disease. The objective was to evaluate the odds of peripheral arterial disease (PAD) or carotid artery stenosis (CAS) among participants with diabetes, CHD, or both, compared with participants without diabetes or CHD, in a nationwide vascular screening database. We hypothesized that diabetes and CHD would confer similar odds of PAD and CAS. METHODS: A cross-sectional analysis of all eligible Life Line Screening Inc participants age 30 to 90 years with ankle brachial indices for PAD (ankle brachial index <0.9 in either leg) and carotid artery duplex ultrasonographic imaging for CAS (internal CAS >/=50%) was performed (N=3,522,890). RESULTS: Diabetes and CHD were present in 372,330 (10.7%) and 182,760 (5.8%) of participants, respectively; PAD and CAS were present in 155,000 (4.4%) and 130,347 (3.7%) of participants. After multivariable adjustment, PAD odds were 1.56 (95% CI 1.54-1.59) and 1.69 (95% CI 1.65-1.73) for participants with diabetes or CHD, respectively. Participants with both diabetes and CHD had 2.75-fold increased odds of PAD (95% CI 2.66-2.85). Findings were similar for CAS; compared with no diabetes or CHD, CAS odds increased for participants with diabetes alone (1.53, 95% CI 1.50-1.56), CHD alone (1.72, 95% CI 1.68-1.76), and both diabetes and CHD (2.57, 95% CI 2.49-2.66). Findings were consistent for women and men. CONCLUSION: In a large database of more than 3.5 million self-referred participants, diabetes was a CHD risk equivalent for PAD and CAS, and participants with comorbid diabetes and CHD had an especially robust association with PAD and CAS. Counseling regarding screening and prevention of peripheral vascular disease may be useful for patients with diabetes.

The underlying pathology of arsenic-related cardiovascular disease (CVD) is unknown. Few studies have evaluated pathways through thrombosis and inflammation for arsenic-related CVD, especially at low-moderate arsenic exposure levels (<100 mug/L in drinking water). We evaluated the association of chronic low-moderate arsenic exposure, measured as the sum of inorganic and methylated arsenic species in urine (SigmaAs), with plasma biomarkers of thrombosis and inflammation in American Indian adults (45-74 years) in the Strong Heart Study. We evaluated the cross-sectional and longitudinal associations between baseline SigmaAs with fibrinogen at three visits (baseline, 1989-91; Visit 2, 1993-95, Visit 3, 1998-99) using mixed models and the associations between baseline SigmaAs and Visit 2 plasminogen activator inhibitor-1 (PAI-1) and high sensitivity C-reactive protein (hsCRP) using linear regression. Median (interquartile range) concentrations of baseline SigmaAs and fibrinogen, and Visit 2 hsCRP and PAI-1 were 8.4 (5.1, 14.3) mug/g creatinine, 346 (304, 393) mg/dL, 44 (30, 67) mg/L, and 3.8 (2.0, 7.0) ng/mL, respectively. Comparing the difference between the 75th and the 25th percentile of SigmaAs (14.3 vs. 5.1 mug/g creatinine), SigmaAs was positively associated with baseline fibrinogen among those with diabetes (adjusted geometric mean ratio (GMR): 1.05, 95% CI: 1.02, 1.07) not associated among those without diabetes (GMR: 1.01, 95% CI: 0.99, 1.02) (p-interaction for diabetes = 0.014), inversely associated with PAI-1 (GMR: 0.94, 95% CI: 0.90, 0.99), and not associated with hsCRP (GMR: 1.00, 95% CI: 0.93, 1.08). We found no evidence for an association between baseline SigmaAs and annual change in fibrinogen over follow-up (p-interaction = 0.28 and 0.12 for diabetes and non-diabetes, respectively). Low-moderate arsenic exposure was positively associated with baseline fibrinogen in participants with diabetes and unexpectedly inversely associated with PAI-1. Further research should evaluate the role of prothrombotic factors in arsenic-related cardiovascular disease.

At high levels, inorganic arsenic exposure is linked to peripheral arterial disease (PAD) and cardiovascular disease. To our knowledge, no prior study has evaluated the association between low-to-moderate arsenic exposure and incident PAD by ankle brachial index (ABI). We evaluated this relationship in the Strong Heart Study, a large population-based cohort study of American Indian communities. A total of 2,977 and 2,966 PAD-free participants who were aged 45-74 years in 1989-1991 were reexamined in 1993-1995 and 1997-1999, respectively, for incident PAD defined as either ABI <0.9 or ABI >1.4. A total of 286 and 206 incident PAD cases were identified for ABI <0.9 and ABI >1.4, respectively. The sum of inorganic and methylated urinary arsenic species ( summation operatorAs) at baseline was used as a biomarker of long-term exposure. Comparing the highest tertile of summation operatorAs with the lowest, the adjusted hazard ratios were 0.57 (95% confidence interval (CI): 0.32, 1.01) for ABI <0.9 and 2.24 (95% CI: 1.01, 4.32) for ABI >1.4. Increased arsenic methylation (as percent dimethylarsinate) was associated with a 2-fold increased risk of ABI >1.4 (hazard ratio = 2.04, 95% CI: 1.02, 3.41). Long-term low-to-moderate summation operatorAs and increased arsenic methylation were associated with ABI >1.4 but not with ABI <0.9. Further studies are needed to clarify whether diabetes and enhanced arsenic metabolism increase susceptibility to the vasculotoxic effects of arsenic exposure.

BACKGROUND: Epidemiological studies in humans that have evaluated the association between fine particulate matter (PM2.5) and atherosclerosis have yielded mixed results. DESIGN: In order to further investigate this relationship, we conducted a comprehensive search for studies published through May 2014 and performed a meta-analysis of all available observational studies that investigated the association between PM2.5 and three noninvasive measures of clinical and subclinical atherosclerosis: carotid intima media thickness, arterial calcification, and ankle-brachial index. METHODS AND RESULTS: Five reviewers selected studies based on predefined inclusion criteria. Pooled mean change estimates and 95% confidence intervals were calculated using random-effects models. Assessment of between-study heterogeneity was performed where the number of studies was adequate. Our pooled sample included 11,947 subjects for carotid intima media thickness estimates, 10,750 for arterial calcification estimates, and 6497 for ankle-brachial index estimates. Per 10 microg/m(3) increase in PM2.5 exposure, carotid intima media thickness increased by 22.52 microm but this did not reach statistical significance (p = 0.06). We did not find similar associations for arterial calcification (p = 0.44) or ankle-brachial index (p = 0.85). CONCLUSION: Our meta-analysis supports a relationship between PM2.5 and subclinical atherosclerosis measured by carotid intima media thickness. We did not find a similar relationship between PM2.5 and arterial calcification or ankle-brachial index, although the number of studies was small.