Circulating CD36 and fractalkine levels are associated with vulnerable plaque progression in patients with unstable angina pectoris

Diagnostic value of end-tidal carbon dioxide in the differential diagnosis of unstable angina and non-cardiac chest pain

OBJECTIVE

This study aims to investigate the diagnostic value of End-tidal carbon dioxide (ETCO₂) measured non-invasively at the bedside in order to distinguish between unstable angina pectoris (UAP) and non-cardiac chest pain among patients who present to the emergency department with chest pain without a history of cardiac pathology.

MATERIAL AND METHODS

This clinical study is a prospective case-control study among patients presenting to the emergency department of a tertiary hospital with chest pain. After evaluating the inclusion and exclusion criteria, the patients were divided into two groups: 62 patients with UAP and 62 patients with non-cardiac chest pain. Receiver Operating Characteristic (ROC) analysis was used to determine the cut-off in diagnostic value measurements. For UAP prediction, the odds ratio of ETCO₂ (including 95% confidence intervals) was calculated using univariate with binary logistic regression analysis.

RESULTS

ETCO₂ had an excellent diagnostic power in detecting UAP, with 35 cut-offs determined (AUC: 0.84, 95% Cl: 0.76-0.90, p < 0.001). When ETCO₂, which affects both non-cardiac chest pain and UAP, is evaluated, an ETCO2 of <35 is statistically significant and 9.74 times more common among UAP patients than patients with non-cardiac chest pain.

CONCLUSION

ETCO₂, a non-invasive parameter that can be measured immediately at the bedside, may be proposed as a potential biomarker for differentiating patients with UAP from those with non-cardiac chest pain.

The Impact of Cytokines in Coronary Atherosclerotic Plaque: Current Therapeutic Approaches

Coronary atherosclerosis is a chronic pathological process that involves inflammation together with endothelial dysfunction and lipoprotein dysregulation. Experimental studies during the past decades have established the role of inflammatory cytokines in coronary artery disease, namely interleukins (ILs), tumor necrosis factor (TNF)-α, interferon-γ, and chemokines. Moreover, their value as biomarkers in disease development and progression further enhance the validity of this interaction. Recently, cytokine-targeted treatment approaches have emerged as potential tools in the management of atherosclerotic disease. IL-1β, based on the results of the CANTOS trial, remains the most validated option in reducing the residual cardiovascular risk. Along the same line, colchicine was also proven efficacious in preventing major adverse cardiovascular events in large clinical trials of patients with acute and chronic coronary syndrome. Other commercially available agents targeting IL-6 (tocilizumab), TNF-α (etanercept, adalimumab, infliximab), or IL-1 receptor antagonist (anakinra) have mostly been assessed in the setting of other inflammatory diseases and further testing in atherosclerosis is required. In the future, potential targeting of the NLRP3 inflammasome, anti-inflammatory IL-10, or atherogenic chemokines could represent appealing options, provided that patient safety is proven to be of no concern.

Emerging Role of Fractalkine in the Treatment of Rheumatic Diseases

Rheumatoid arthritis (RA) is an autoimmune disorder that affects joints and is characterized by synovial hyperplasia and bone erosion associated with neovascularization and infiltration of proinflammatory cells. The introduction of biological disease-modifying anti-rheumatic drugs has dramatically changed the treatment of RA over the last 20 years. However, fewer than 50% of RA patients enter remission, and 10–15% are treatment refractory. There is currently no cure for RA. Fractalkine (FKN, also known as CX3CL1) is a cell membrane-bound chemokine that can be induced on activated vascular endothelial cells. FKN has dual functions as a cell adhesion molecule and a chemoattractant. FKN binds specifically to the chemokine receptor CX3CR1, which is selectively expressed on subsets of immune cells such as patrolling monocytes and killer lymphocytes. The FKN–CX3CR1 axis is thought to play important roles in the initiation of the inflammatory cascade and can contribute to exacerbation of tissue injury in inflammatory diseases. Accordingly, studies in animal models have shown that inhibition of the FKN–CX3CR1 axis not only improves rheumatic diseases but also reduces associated complications, such as pulmonary fibrosis and cardiovascular disease. Recently, a humanized anti-FKN monoclonal antibody, E6011, showed promising efficacy with a dose-dependent clinical response and favorable safety profile in a Phase 2 clinical trial in patients with RA (NCT02960438). Taken together, the preclinical and clinical results suggest that E6011 may represent a new therapeutic approach for rheumatic diseases by suppressing a major contributor to inflammation and mitigating concomitant cardiovascular and fibrotic diseases. In this review, we describe the role of the FKN–CX3CR1 axis in rheumatic diseases and the therapeutic potential of anti-FKN monoclonal antibodies to fulfill unmet clinical needs.

Association Between Unstable Angina and CXCL17: a New Potential Biomarker

Atherosclerosis and chemokines are strongly related, but the role of the chemokine CXCL17 in atherogenesis is still poorly understood. We aim to investigate the serum CXCL17 levels in different stages of patients with coronary heart disease and explore whether these differences contribute to atherosclerosis. In the current prospective study, we enrolled 48 patients with unstable angina (UA), 51 patients with stable angina (SA) and 41 patients for the control group (CG). All subjects were diagnosed by coronary angiography and Gensini score was used to evaluate the severity of coronary artery disease. The CXCL17 levels were determined using ELISA, while lipid metabolism indicators and high sensitivity C-reactive protein (hs-CRP) were detected by automatic biochemical analyzer. We observed that the unstable angina group had higher CXCL17 levels compared with the stable angina and the control group. The logistic regression analysis showed that CXCL17 was an independent risk factor for unstable angina. Our results showed that CXCL17 was also statistically correlated with hs-CRP, while it was irrelevant with Gensini score. CXCL17 levels were associated with activity of inflammatory response and the instability of atherosclerotic plaques. These results suggest that CXCL17 elevation may be a potential new biomarker of unstable angina.

Cholesterol transport system: An integrated cholesterol transport model involved in atherosclerosis

Atherosclerosis, the pathological basis of most cardiovascular disease (CVD), is closely associated with cholesterol accumulation in the arterial intima. Excessive cholesterol is removed by the reverse cholesterol transport (RCT) pathway, representing a major antiatherogenic mechanism. In addition to the RCT, other pathways are required for maintaining the whole-body cholesterol homeostasis. Thus, we propose a working model of integrated cholesterol transport, termed the cholesterol transport system (CTS), to describe body cholesterol metabolism. The novel model not only involves the classical view of RCT but also contains other steps, such as cholesterol absorption in the small intestine, low-density lipoprotein uptake by the liver, and transintestinal cholesterol excretion. Extensive studies have shown that dysfunctional CTS is one of the major causes for hypercholesterolemia and atherosclerosis. Currently, several drugs are available to improve the CTS efficiently. There are also several therapeutic approaches that have entered into clinical trials and shown considerable promise for decreasing the risk of CVD. In recent years, a variety of novel findings reveal the molecular mechanisms for the CTS and its role in the development of atherosclerosis, thereby providing novel insights into the understanding of whole-body cholesterol transport and metabolism. In this review, we summarize the latest advances in this area with an emphasis on the therapeutic potential of targeting the CTS in CVD patients.

The upregulated scavenger receptor CD36 is associated with the progression of nontarget lesions after stent implantation in atherosclerotic rabbits

Background

The incidence of recurrent cardiovascular events from the progression of nontarget lesions (NTLs) is high for percutaneous coronary intervention-treated patients. However, the underlying mechanisms have not been thoroughly elucidated.

Methods

In this study, ten atherosclerotic rabbits with multiple plaques in the upper and lower segments of abdominal aorta (group A) were randomly divided into two subgroups: group A1 underwent intravascular ultrasound examination and stent implantation in the lower segments of the abdominal aorta (n=5), whereas group A2 was without stenting (n=5). Group B was a control group without balloon injury. The serum levels of high-sensitivity CRP, interleukin-6 (IL-6), oxidized low-density lipoprotein, and CD36 were assessed via ELISA at five time points between the 10th and 18th weeks. The upper abdominal aorta was examined via the immunohistochemical stain and Western blotting of matrix metallopeptidase 9 (MMP-9), CD36, IL-6, and tumor necrosis factor α.

Results

As a result, we found that stent implantation aggravated serum levels of CD36, oxidative stress, and inflammatory cytokines. Meanwhile, the upper abdominal arterial plaque burden significantly increased after stenting by intravascular ultrasound. Immunohistochemistry and Western blotting showed that the local NTLs’ matrix metallopeptidase 9, CD36, IL-6, and tumor necrosis factor α expressions in group A1 were significantly higher than those in groups A2 and B (P<0.05–0.01). More importantly, a strong correlation was identified between CD36 expression and NTLs’ plaque burden before the rabbits were killed.

Conclusion

Taken together, stent implantation accelerated inflammation, induced oxidative stress, and increased the NTLs’ progression, which were associated with the upregulated CD36 expression.

Identified key genes related to carotid atheroma plaque from gene expression chip

As one of the leading reason in morbidity and death in the world, atherosclerosis is usually associated with vessel stenosis, ulceration, and inflammatory cell infiltration. However, the formation mechanism of atheroma plaque is unknown. In this research, we have used bioinformatics tools to identify 118 differential expression genes from a GEO dataset. Besides, we also revealed KYNU as a crucial gene in atheroma plaque development.