Small artery dilation and endothelial markers in cardiovascular risk patients

Prevalence and Determinants of Peripheral Microvascular Endothelial Dysfunction in Rheumatoid Arthritis Patients: A Multicenter Cross-Sectional Study

Objectives

To define the prevalence and determinants of peripheral microvascular endothelial dysfunction (ED) in a large series of rheumatoid arthritis (RA) patients free of previous cardiovascular events.

Materials and Methods

Data from 874 RA patients enrolled in the EDRA study (Endothelial Dysfunction Evaluation for Coronary Heart Disease Risk Estimation in Rheumatoid Arthritis—ClinicalTrials.gov: NCT02341066) were analyzed. Log-transformed reactive hyperemia index (Ln-RHI) was evaluated by peripheral arterial tonometry (PAT) using the EndoPAT2000 device: values of Ln-RHI < 0.51 were considered indicative of peripheral ED.

Results

Peripheral microvascular ED was documented in one-third of RA patients (33.5%); in multiple logistic regression analysis, ACPA negativity and higher triglycerides concentrations were independently associated with the presence of peripheral ED [OR (95% CI) = 1.708 (1.218–2.396), p < 0.01 and OR (95% CI) = 1.005 (1.002–1.009), p < 0.01, respectively]. Multiple regression analysis showed a positive correlation between Ln-RHI values and systolic blood pressure and HDL cholesterol levels; furthermore, higher values of Ln-RHI were associated with ACPA positivity, while smoking habit was associated with lower Ln-RHI values.

Conclusions

This study demonstrates for the first time a high prevalence of peripheral microvascular ED in patients with RA free of previous cardiovascular events that appear to be only partially driven by traditional cardiovascular risk factors. The association between ACPA negativity and ED warrants further exploration.

Epigenetics and social context: implications for disparity in cardiovascular disease

BACKGROUND

Although it is well established that African Americans (AA) experience greater social stressors than non-Hispanic Whites (NHW), the extent to which early life adversity and cumulative social stressors such as perceived discrimination, neighborhood violence, subjective social status, and socioeconomic status contribute to disparity in coronary heart disease (CHD) and stroke between AA and NHW are not well understood.

PURPOSE

The purpose of this paper is to propose a conceptual model based upon McEwen's Allostatic Load Model suggesting how the relationships among social context, early life adversity, psychological stress, inflammation, adaptation, and epigenetic signature may contribute to the development of CHD and ischemic stroke. We hypothesize that social context and prior life adversity are associated with genome-wide as well as gene-specific epigenetic modifications that confer a proinflammatory epigenetic signature that mediates an enhanced proinflammatory state. Exposure to early life adversity, coupled with an increased allostatic load places individuals at greater risk for inflammatory based diseases, such as CHD and ischemic stroke.

RESULTS

Based on a review of the literature, we propose a novel model in which social context and psychological stress, particularly during early life, engenders a proinflammatory epigenetic signature, which drives a heightened inflammatory state that increases risk for CHD and stroke. In the proposed model, a proinflammatory epigenetic signature and adaptation serve as mediator variables.

CONCLUSIONS

Understanding the extent to which epigenetic signature bridges the psycho-social environment with inflammation and risk for CHD may yield novel biomarkers that can be used to assess risk, development, and progression of CHD/stroke. Epigenetic biomarkers may be used to inform preventive and treatment strategies that can be targeted to those most vulnerable, or to those with early signs of CHD, such as endothelial dysfunction. Furthermore, epigenetic approaches, including lifestyle modification and stress reduction programs, such as mindfulness-based stress reduction, offer promise to reduce health inequity linked to social disadvantage, as emerging evidence demonstrates that adverse epigenetic marks can be reversed.

Endothelial function progressively deteriorates during normal pregnancy

OBJECTIVE

To elucidate changes in endothelial function throughout the gestational period in normal pregnancy and its relationship with plasma soluble fms-like tyrosine kinase-1 (sFlt-1) levels.

METHODS

Endothelial function was evaluated by reactive hyperemia index (RHI) using Endo-PAT2000 and plasma sFlt-1 levels were measured simultaneously by ELISA.

RESULTS

RHI gradually deteriorated with increasing gestational age. Plasma sFlt-1 levels exhibited a gradual increase at late pregnancy and were inversely correlated with RHI.

CONCLUSION

Maternal endothelial function gradually deteriorates with increasing gestational age and there is an inverse correlation between endothelial function and plasma sFlt-1 levels in normal pregnancy.

Low-carbohydrate, high-protein, high-fat diet alters small peripheral artery reactivity in metabolic syndrome patients

BACKGROUND

Low carbohydrate diets have become increasingly popular for weight loss. Although they may improve some metabolic markers, particularly in type 2 diabetes mellitus (T2D) or metabolic syndrome (MS), their net effect on vascular function remains unclear.

OBJECTIVE

Evaluate the relation between dietary macronutrient composition and the small artery reactive hyperaemia index (saRHI), a marker of small artery vascular function, in a cohort of MS patients.

DESIGN

This cross-sectional study included 160 MS patients. Diet was evaluated by a 3-day food-intake register and reduced to a novel low-carbohydrate diet score (LCDS). Physical examination, demographic, biochemical and anthropometry parameters were recorded, and saRHI was measured in each patient.

RESULTS

Individuals in the lowest LCDS quartile (Q1; 45% carbohydrate, 19% protein, 31% fat) had higher saRHI values than those in the top quartile (Q4; 30% carbohydrate, 25% protein, 43% fat) (1.84±0.42 vs. 1.55±0.25, P=.012). These results were similar in T2D patients (Q1=1.779±0.311 vs. Q4=1.618±0.352, P=.011) and also in all of the MS components, except for low HDLc. Multivariate analysis demonstrated that individuals in the highest LCDS quartile, that is, consuming less carbohydrates, had a significantly negative coefficient of saRHI which was independent of confounders (HR: -0.747; 95%CI: 0.201, 0.882; P=.029).

CONCLUSIONS

These data suggest that a dietary pattern characterized by a low amount of carbohydrate, but reciprocally higher amounts of fat and protein, is associated with poorer vascular reactivity in patients with MS and T2D.

FABP4 induces vascular smooth muscle cell proliferation and migration through a MAPK-dependent pathway

Purpose

The migration and proliferation of vascular smooth muscle cells play crucial roles in the development of atherosclerotic lesions. This study examined the effects of fatty acid binding protein 4 (FABP4), an adipokine that is associated with cardiovascular risk, endothelial dysfunction and proinflammatory effects, on the migration and proliferation of human coronary artery smooth muscle cells (HCASMCs).

Methods and Results

A DNA 5-bromo-2′-deoxy-uridine (BrdU) incorporation assay indicated that FABP4 significantly induced the dose-dependent proliferation of HCASMCs with a maximum stimulatory effect at 120 ng/ml (13% vs. unstimulated cells, p<0.05). An anti-FABP4 antibody (40 ng/ml) significantly inhibited the induced cell proliferation, demonstrating the specificity of the FABP4 proliferative effect. FABP4 significantly induced HCASMC migration in a dose-dependent manner with an initial effect at 60 ng/ml (12% vs. unstimulated cells, p<0.05). Time-course studies demonstrated that FABP4 significantly increased cell migration compared with unstimulated cells from 4 h (23%vs. 17%, p<0.05) to 12 h (74%vs. 59%, p<0.05). Pretreatment with LY-294002 (5 µM) and PD98059 (10 µM) blocked the FABP4-induced proliferation and migration of HCASMCs, suggesting the activation of a kinase pathway. On a molecular level, we observed an up-regulation of the MAPK pathway without activation of Akt. We found that FABP4 induced the active forms of the nuclear transcription factors c-jun and c-myc, which are regulated by MAPK cascades, and increased the expression of the downstream genes cyclin D1 and MMP2, CCL2, and fibulin 4 and 5, which are involved in cell cycle regulation and cell migration.

Conclusions

These findings indicate a direct effect of FABP4 on the migration and proliferation of HCASMCs, suggesting a role for this adipokine in vascular remodelling. Taken together, these results demonstrate that the FABP4-induced DNA synthesis and cell migration are mediated primarily through a MAPK-dependent pathway that activates the transcription factors c-jun and c-myc in HCASMCs.

Maternal obesity is associated with the formation of small dense LDL and hypoadiponectinemia in the third trimester

CONTEXT

Maternal obesity is associated with high plasma triglyceride, poor vascular function, and an increased risk for pregnancy complications. In normal-weight pregnant women, higher triglyceride is associated with increased small, dense low-density lipoprotein (LDL).

HYPOTHESIS

In obese pregnancy, increased plasma triglyceride concentrations result in triglyceride enrichment of very low-density lipoprotein-1 particles and formation of small dense LDL via lipoprotein lipase.

DESIGN

Women (n = 55) of body mass index of 18-46 kg/m(2) were sampled longitudinally at 12, 26, and 35 weeks' gestation and 4 months postnatally.

SETTING

Women were recruited at hospital antenatal appointments, and study visits were in a clinical research suite.

OUTCOME MEASURES

Plasma concentrations of lipids, triglyceride-rich lipoproteins, lipoprotein lipase mass, estradiol, steroid hormone binding globulin, insulin, glucose, leptin, and adiponectin were determined.

RESULTS

Obese women commenced pregnancy with higher plasma triglyceride, reached the same maximum, and then returned to higher postnatal levels than normal-weight women. Estradiol response to pregnancy (trimester 1-3 incremental area under the curve) was positively associated with plasma triglyceride response (r(2) adjusted 25%, P < .001). In the third trimester, the proportion of small, dense LDL was 2-fold higher in obese women than normal-weight women [mean (SD) 40.7 (18.8) vs 21.9 (10.9)%, P = .014], and 35% of obese, 14% of overweight, and none of the normal-weight women displayed an atherogenic LDL subfraction phenotype. The small, dense LDL mass response to pregnancy was inversely associated with adiponectin response (17%, P = .013).

CONCLUSIONS

Maternal obesity is associated with an atherogenic LDL subfraction phenotype and may provide a mechanistic link to poor vascular function and adverse pregnancy outcome.

Negative effect of a low-carbohydrate, high-protein, high-fat diet on small peripheral artery reactivity in patients with increased cardiovascular risk

Low-carbohydrate diets have become increasingly popular for weight loss. Although they may improve some metabolic markers, particularly in type 2 diabetes mellitus (T2D) or the metabolic syndrome (MS), their net effect on arterial wall function remains unclear. The objective was to evaluate the relation between dietary macronutrient composition and the small artery reactive hyperaemia index (saRHI), a marker of small artery endothelial function, in a cohort of patients at increased cardiovascular (CV) risk. The present cross-sectional study included 247 patients. Diet was evaluated by a 3-d food-intake register and reduced to a novel low-carbohydrate diet score (LCDS). Physical examination, demographic, biochemical and anthropometry parameters were recorded, and the saRHI was measured in each patient. Individuals in the lowest LCDS quartile (Q1, 45 % carbohydrate; 20 % protein; 32 % fat) had higher saRHI values than those in the top quartile (Q4, 29 % carbohydrate, 24 % protein, 40 % fat; 1·66 (sd 0·41) v. 1·52 (sd 0·22), P= 0·037). These results were particularly strong in patients with the MS (Q1 = 1·82 (sd 0·32) v. Q4 = 1·61 (sd 027); P= 0·021) and T2D (Q1 = 1·78 (sd 0·31) v. Q4 = 1·62 (sd 0·35); P= 0·011). Multivariate analysis demonstrated that individuals in the highest LCDS quartile had a significantly negative coefficient of saRHI, which was independent of confounders (OR − 0·85; 95 % CI 0·19, 0·92; P= 0·031). These findings suggest that a dietary pattern characterised by a low amount of carbohydrate, but high amounts of protein and fat, is associated with a poorer small artery vascular reactivity in patients with increased CV risk.

Fatty acid-binding protein 4 impairs the insulin-dependent nitric oxide pathway in vascular endothelial cells

Background

Recent studies have shown that fatty acid-binding protein 4 (FABP4) plasma levels are associated with impaired endothelial function in type 2 diabetes (T2D). In this work, we analysed the effect of FABP4 on the insulin-mediated nitric oxide (NO) production by endothelial cells in vitro.

Methods

In human umbilical vascular endothelial cells (HUVECs), we measured the effects of FABP4 on the insulin-mediated endothelial nitric oxide synthase (eNOS) expression and activation and on NO production. We also explored the impact of exogenous FABP4 on the insulin-signalling pathway (insulin receptor substrate 1 (IRS1) and Akt).

Results

We found that eNOS expression and activation and NO production are significantly inhibited by exogenous FABP4 in HUVECs. FABP4 induced an alteration of the insulin-mediated eNOS pathway by inhibiting IRS1 and Akt activation. These results suggest that FABP4 induces endothelial dysfunction by inhibiting the activation of the insulin-signalling pathway resulting in decreased eNOS activation and NO production.

Conclusion

These findings provide a mechanistic linkage between FABP4 and impaired endothelial function in diabetes, which leads to an increased cardiovascular risk.