Relationship between coronary endothelial function and coronary calcification in early atherosclerosis

ILF3 is responsible for hyperlipidemia-induced arteriosclerotic calcification by mediating BMP2 and STAT1 transcription

Calcification is common in atherosclerotic plaque and can induce vulnerability, which further leads to myocardial infarction, plaque rupture and stroke. The mechanisms of atherosclerotic calcification are poorly characterized. Interleukin enhancer binding factor 3 (ILF3) has been identified as a novel factor affecting dyslipidemia and stroke subtypes. However, the precise role of ILF3 in atherosclerotic calcification remains unclear. In this study, we used smooth muscle-conditional ILF3 knockout (ILF3SM-KO) and transgenic mice (ILF3SM-Tg) and macrophage-conditional ILF3 knockout (ILF3M-KO) and transgenic (ILF3M-Tg) mice respectively. Here we showed that ILF3 expression is increased in calcified human aortic vascular smooth muscle cells (HAVSMCs) and calcified atherosclerotic plaque in humans and mice. We then found that hyperlipidemia increases ILF3 expression and exacerbates calcification of VSMCs and macrophages by regulating bone morphogenetic protein 2 (BMP2) and signal transducer and activator of transcription 1 (STAT1) transcription. We further explored the molecular mechanisms of ILF3 in atherosclerotic calcification and revealed that ILF3 acts on the promoter regions of BMP2 and STAT1 and mediates BMP2 upregulation and STAT1 downregulation, which promotes atherosclerotic calcification. Our results demonstrate the effect of ILF3 in atherosclerotic calcification. Inhibition of ILF3 may be a useful therapy for preventing and even reversing atherosclerotic calcification.

Sedentary Behavior in Childhood, Lower Arterial Compliance and Decreased Endothelial Function-Cross Sectional Data From a German School Cohort

BACKGROUND

Endothelial function by flow-mediated dilatation assesses early markers of atherosclerotic progression. Greater amounts of physical activity and physical fitness in children are associated with cardiovascular health benefits. We aimed to explore factors, influencing endothelial function and arterial compliance in a cohort of healthy school children.

METHODS

The 94 participants (41 girls, 53 boys) in the study were young, healthy children from a German school cohort. Anthropometric data, body composition and blood pressure were assessed. Blood was drawn (8 h overnight fast), assessing total cholesterol, high density lipoprotein and low density lipoprotein and triglycerides. Endothelial function was diagnosed by flow-mediated dilatation with ultrasonography (ALOKA/Hitachi, Prosound alpha 6). Tracking gates were set on the intima in B-mode. The waveform of diameter changes over the cardiac cycle was displayed in real time using the FMD-mode of the eTRACKING system. Changes in arterial diameter at baseline, ischaemia and vasodilatation were measured. A symptom limited pulmonary exercise test on a bicycle ergometer was performed to test cardiorespiratory fitness. Physical activity was assessed using GT3x accelerometers (Actigraph, USA), over 4 days (including 1 week-end day), with a minimum wear-time duration of 10 h.

RESULTS

The median age was 12.2 years (11.8-12.8). Children were normal weight, blood lipid profiles (cholesterol, high-density lipoprotein, low-density lipoprotein, triglyceride) were in normal range. Baseline measurements during the diagnostics of endothelial function revealed higher arterial compliance of the brachial artery in boys. Boys' cardiorespiratory fitness was higher than compared to girls. Boys met the recommendations of 60 min moderate to vigorous activity, whereas girls were significantly less active and did not meet current recommendations. More time spent in sedentary activity was the main predictor for lower arterial compliance (adjusted for age and sex), accounting for 14% of the variance. No significant model revealed, analyzing the influencing factors such as anthropometric data, blood lipids, physical activity and fitness on endothelial function.

CONCLUSION

This is the first study on endothelial function in association to objectively measured physical activity and cardiorespiratory fitness in healthy school children in Germany. The study highlights the importance of reducing time spent being sedentary to maintain endothelial health.

Endothelial dysfunction is not a predictor of outcome in chronic obstructive pulmonary disease

Background

Local airway inflammation may cause systemic changes which result in endothelial dysfunction. Only a few studies have used reactive hyperemia peripheral arterial tonometry (RH-PAT) in patients with chronic obstructive pulmonary disease (COPD) in order to measure their endothelial dysfunction.

Objective

To determine the efficacy of endothelial dysfunction, measured by RH-PAT, in assessing disease severity and systemic burden in a cohort of COPD patients.

Methods

In this prospective, monocentric study, 157 patients with moderate to very severe COPD (GOLD class II-IV) were examined for endothelial dysfunction using RH-PAT (Itamar medical Ltd., Caesarea, Israel). In a nested-cohort, examination was repeated at exacerbation. The association between reactive hyperemia index (RHI), augmentation index (AI) and disease severity and outcome parameters was analysed.

Results

57% of the COPD patients had a dysfunctional endothelium and the median (IQR) RHI was 1.42 (1.27–1.53). Exacerbation of COPD was not associated with a significant change in RHI (p = 0.625) or ΑΙ (p = 0.530). None of the diagnostic or clinical outcomes of COPD was associated with RHI or arterial stiffness.

Conclusion

Endothelial dysfunction is common in COPD. However, it does not seem to be a predictor neither of disease severity, nor of outcome and does not change during exacerbations of the disease.

The relationship between endothelial function and aortic valve calcification: Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Aortic valve calcification (AVC) may be associated with atherogenic processes arising from endothelial dysfunction (ED). Limited data is available about the relationship between ED, defined by flow mediated dilation (FMD%) and biomarkers, and the prevalence and progression of AVC in a multiethnic population.

METHODS

A sample of 3475 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA), with both initial and repeat CT scans at a mean of 2.65 ± 0.84 years and FMD% and serologic markers of ED [ C-reactive protein (CRP), Von Willebrand factor (vWF), Plasminogen Activator Inhibitor (PAI), fibrinogen, Interleukin 6 (IL6), E-selectin and ICAM-1 (Intercellular Adhesion Molecule 1)], were analyzed. Multivariate modeling evaluated the association between ED and the prevalent AVC and AVC progression.

RESULTS

The median levels of FMD% was lower and vWF%, fibrinogen, IL6 and ICAM-1 were significantly higher in the AVC prevalence group versus no AVC prevalence (all p < 0.001). In the fully adjusted model for established risk factors, decreasing FMD% or increasing biomarkers was not independently associated with AVC prevalence [OR FMD% 1.028 (0.786, 1.346), CRP 0.981 (0.825, 1.168), vWF 1.132 (0.559, 2.292), PAI 1.124 (0.960, 1.316), fibrinogen 1.116 (0.424, 2.940), IL6 1.065 (0.779, 1.456), E-selectin 0.876 (0.479, 1.602) and ICAM-1 1.766 (0.834, 3.743)]. In the AVC progression group, FMD%, vWF%, fibrinogen and IL6 were significantly different (p < 0.05). After adjusting for cardiac risk factors, AVC progression was not independently associated with decreasing FMD% or increasing biomarkers [OR FMD% 1.105 (0.835, 1.463), CRP 1.014 (0.849, 1.210), vWF% 1.132 (0.559, 2.292), PAI 1.124 (0.960, 1.316), fibrinogen 0.909 (0.338, 2.443), IL6 1.061 (0.772, 1.459), E-selectin 0.794 (0.426, 1.480) and ICAM-1 0.998 (0.476, 2.092)].

CONCLUSIONS

Endothelial dysfunction by FMD% and biomarkers is not significantly associated with the prevalence or progression of aortic valve calcification after adjustment for cardiac risk factors.

Peripheral arterial tonometry cannot detect patients at low risk of coronary artery disease

Background

Endothelial dysfunction precedes coronary artery disease (CAD) and can be measured by peripheral arterial tonometry (PAT). We examined the applicability of PAT to detect a low risk of CAD in a chest pain clinic.

Methods

In 93 patients, PAT was performed resulting in reactive hyperaemia (RHI) and augmentation (AIx) indices. Patients were risk classified according to HeartScore, Diamond and Forrester pretest probability (DF), exercise testing (X-ECG), and computed tomography calcium scoring (CCS) and angiography (CTA). Correlations, risk group differences and prediction of revascularisation within 1 year were calculated.

Results

RHI correlated with HeartScore (r = − 0.21, p = 0.05), AIx with DF (r = 0.26, p = 0.01). However, both were not significantly different between normal and ischaemic X-ECG groups. In addition RHI and AIx were similar between low risk as compared with intermediate-to-high risk, based on risk algorithms (RHI: 1.98 (0.67) vs 1.94 (0.78); AIx: 0.0 (21) vs 5.0 (25); p = NS), or CCS and CTA (RHI: 1.99 (0.58) vs 1.89 (0.82); AIx: − 2.0 (24) vs 4.0 (25); p = NS). Finally, RHI and AIx failed to predict revascularisation (RHI: OR 1.42, CI 0.65–3.1; AIx: OR 1.02, CI 0.98–1.05).

Conclusions

PAT cannot detect a low risk of CAD, possibly because RHI and AIx versus X-ECG, CCS and CTA represent independent processes.

Long-term effect of different physical activity levels on subclinical atherosclerosis in middle-aged men: a 25-year prospective study

BACKGROUND

The purpose of the study was to investigate the influence of lifetime physical activity (PA) on selected indices of atherosclerosis in longitudinal observation of middle-aged men.

METHODS

The subject of the study was a cohort of 101 men (mean age 59,7 ± 9,0 years), free of cardiovascular symptoms and treatment, participating in follow-up examinations in the years 1985/90-2011/12. Self-report PA was assessed by interviewer-administered Seven-Day PA Recall and Historical PA questionnaire. Subclinical atherosclerosis was measured by assessing the coronary artery calcification (CAC) according to Agatston's method using multi-slice computed tomography; the carotid intima-media thickness (IMT) using high-resolution B-mode ultrasound; and the reactive hyperemia index (RHI) using peripheral arterial tonometry (EndoPAT2000). The participants were initially divided into three groups according to tertiles of exercise-related energy expenditure (EE) in kcal/week at baseline, i.e. <2050 (low-to-moderate; n = 33), 2050-3840 (high; n = 34), >3840 (very high; n = 34).

RESULTS

The low-to-moderate, high and very high PA groups were comparable in terms of age and atherosclerosis risk factors at baseline. No linear relationship was found between PA and CAC, IMT and RHI. Men who maintained low-to-moderate (n = 26), high (n = 21) and very high (n = 15) PA level had the mean CAC of 286.1 ± 361.9, 10.7 ± 28.9, and 106.1 ± 278.3 (p<0.001 for low-to moderate vs high; p<0.05 for low-to-moderate vs very high); the mean IMT of 0.751 ± 0.19 mm, 0,641 ± 0.26 mm, and 0.750 ± 0.60 mm (p>0.05); and the mean RHI of 1.69 ± 0.4, 2.00 ± 0.4, and 2.13 ± 0.5 (p for trend = 0.050), respectively. No cases of CAC>400, IMT ≥ 0.9 and RHI<1.67 were noted only among men with maintained high PA level. At final examination men with high and very high PA had more favorable cardiometabolic profile than men with lower PA.

CONCLUSIONS

Maintaining regular high PA level through young and middle adulthood may protect against atherosclerosis as measured by CAC, IMT and RHI.

Normal vascular function as a prerequisite for the absence of coronary calcification in patients free of cardiovascular disease and diabetes

BACKGROUND

The absence of coronary artery calcium (CAC) is a marker of very low cardiovascular risk. Endothelial cells may have an effect on the initiation and propagation of arterial calcification. We aimed to identify the relationship between the absence of CAC and endothelial function in individuals without cardiovascular disease and diabetes.

METHODS AND RESULTS

CAC was assessed using electron-beam computed tomography and the calcium score was then computed. Endothelial function was measured by assessing reactive hyperemia-induced vasodilation and expressed by the reactive hyperemia index (RHI). Of 82 patients, 39 had non-detectable calcium (CAC score=0) and 43 had a CAC score >0. In the CAC score=0 group, the prevalence of normal endothelial function was 84.6%, compared to 48.8% in the CAC score >0 group, P=0.001. The absence of CAC was highly correlated with normal endothelial function (γ=0.704, P<0.001). On average, endothelial function was significantly better in the CAC score=0 group than in the CAC score >0 group (RHI 2.2±0.6 vs. 1.8±0.5, P=0.002). In a multivariate logistic regression model, only normal endothelial function (odds ratio [OR] 5.03, 95% confidence interval [CI] 1.55-16.27, P=0.007) and age (years) (OR 0.91, 95% CI 0.86-0.96, P=0.002) were independently associated with the absence of CAC.

CONCLUSIONS

Normal functional status of the vasculature may be important for the prevention of coronary calcification and may partly account for the low cardiovascular risk of absent CAC.

Global array-based transcriptomics from minimal input RNA utilising an optimal RNA isolation process combined with SPIA cDNA probes

BACKGROUND

Technical advances in the collection of clinical material, such as laser capture microdissection and cell sorting, provide the advantage of yielding more refined and homogenous populations of cells. However, these attractive advantages are counter balanced by the significant difficulty in obtaining adequate nucleic acid yields to allow transcriptomic analyses. Established technologies are available to carry out global transcriptomics using nanograms of input RNA, however, many clinical samples of low cell content would be expected to yield RNA within the picogram range. To fully exploit these clinical samples the challenge of isolating adequate RNA yield directly and generating sufficient microarray probes for global transcriptional profiling from this low level RNA input has been addressed in the current report. We have established an optimised RNA isolation workflow specifically designed to yield maximal RNA from minimal cell numbers. This procedure obtained RNA yield sufficient for carrying out global transcriptional profiling from vascular endothelial cell biopsies, clinical material not previously amenable to global transcriptomic approaches. In addition, by assessing the performance of two linear isothermal probe generation methods at decreasing input levels of good quality RNA we demonstrated robust detection of a class of low abundance transcripts (GPCRs) at input levels within the picogram range, a lower level of RNA input (50 pg) than previously reported for global transcriptional profiling and report the ability to interrogate the transcriptome from only 10 pg of input RNA. By exploiting an optimal RNA isolation workflow specifically for samples of low cell content, and linear isothermal RNA amplification methods for low level RNA input we were able to perform global transcriptomics on valuable and potentially informative clinically derived vascular endothelial biopsies here for the first time. These workflows provide the ability to robustly exploit ever more common clinical samples yielding extremely low cell numbers and RNA yields for global transcriptomics.