Phosphorylcholine-Primed Dendritic Cells Aggravate the Development of Atherosclerosis in ApoE-/- Mice.

Background: Atherosclerosis is an inflammatory disease involving activation of adaptive and innate immune responses to antigens, including oxidized low-density lipoprotein (oxLDL) and phosphorylcholine (PC). Dendritic cells (DCs), which are antigen-presenting cells that activate T cells, are present in atherosclerotic lesions and are activated in immune organs. However, the mechanism by which PC promotes atherosclerosis is unclear. Methods and Results: To evaluate whether PC promotes atherosclerosis via DCs, 2×105 DCs activated by PC-keyhole limpet hemocyanin (DCs+PC-KLH) were injected into ApoE-/- mice and the features of the plaques and the effects of the DCs on cellular and humoral immunity against PC-KLH were determined. Mice injected with DCs+PC-KLH had significantly larger atherosclerotic lesions than controls, with increased inflammation in the lesions and plaque instability. Furthermore, DCs+PC-KLH were characterized using flow cytometry after coculture of bone marrow-derived DCs and naïve T cells. DCs+PC-KLH showed an inflammatory phenotype, with increased CD86, CD40, and major histocompatibility complex Class II molecules (MHC-II), which promoted PC-specific T helper (Th) 1 and Th17 cell differentiation in vivo and in vitro. Moreover, 2 weeks after the administration of DCs+PC-KLH to mice, these mice produced PC- and oxLDL-specific IgG2a, compared with no production in the controls. Conclusions: These findings suggest that DCs presenting PC promote specific immunity to PC, increase lesion inflammation, and accelerate atherosclerosis, which may explain how PC promotes atherosclerosis.

Elevated Levels of Very Low-density Lipoprotein Cholesterol Independently Associated with In-stent Restenosis in Diabetic Patients after Drug-eluting Stent Implantation.

BACKGROUND: High rate of in-stent restenosis (ISR) remained an unsolved clinical problem in clinical practice, especially among patients with diabetes mellitus (DM). Diabetic patients often had hypertriglyceridemia with elevated levels of very low-density lipoprotein cholesterol (VLDL-C). Increasing evidence suggested that VLDL-C was known as a significant risk factor for atherosclerosis and had been recommended as a treatment target by current dyslipidemia guidelines. However, the role of VLDL-C in the occurrence and development of ISR in coronary artery disease (CAD) patients with DM had not been studied. The aim of this study was to evaluate the association between the elevated levels of VLDL-C and the risk of ISR in CAD patients with DM. METHODS: A total of 1390 diabetic patients, who underwent coronary drug-eluting stent (DES) implantation at Beijing Anzhen Hospital and followed up by angiography within 6-24 months, were consecutively enrolled. Patients' demographic and clinical characteristics, including age, gender, CAD risk factors, family history, life style, medical history, and coronary angiographic information, were collected carefully at baseline percutaneous coronary intervention and follow-up angiography. Multivariate Cox's proportional hazards regression modeling using the step-wise method (entry, 0.05; removal, 0.05) was used to determine the independent risk associated with ISR in diabetic patients. RESULTS: Finally, 1206 of patients were included in this study. ISR occurred in 132/1206 diabetic patients (10.9%) by follow-up angiography. Patients with ISR had elevated median serum VLDL-C levels compared with those without ISR (0.65 mmol/L vs. 0.52 mmol/L, P = 0.030). The multivariate regression analysis showed that VLDL-C was significantly associated with the risk of ISR in diabetic CAD patients (hazard ratio [HR] = 1.15, 95% confidence interval [CI]: 1.03-1.29, P = 0.017). The HR for the risk of ISR associated with VLDL-C level ≥0.52 mmol/L was 3.01 (95% CI: 1.24-7.34, P = 0.015). CONCLUSION: The elevated level of serum VLDL-C was a significant and independent risk factor for ISR in diabetic CAD patients after coronary DES implantation.

Elevated IL-37 levels in the plasma of patients with severe coronary artery calcification.

BACKGROUND: Coronary artery calcification (CAC) is a predictor of cardiovascular events and plaque burden and is closely associated with chronic inflammation. Interleukin (IL)-37 is a newly discovered member of the IL-1 family and is considered an anti-inflammatory cytokine. Our recent study on mice indicated that IL-37 could attenuate atherosclerosis and vascular calcification, which suggests that IL-37 could be associated with the development of atherosclerosis and related diseases. The aim of this study was to investigate if IL-37 plays a role in the progression of CAC in patients. METHODS: Two hundred participants with suspected cardiovascular disease were recruited. The levels of plasma IL-37, osteoprotegerin (OPG), hypersensitive C-reactive protein (hsCRP) together with other biochemical parameters were measured, and a coronary calcium assessment was carried out by multi-detector row CT. A score of < 10 AU (Agatston units) denotes an absence of CAC, a score of 11-100 AU denotes mild CAC, 101-400 denotes moderate CAC, and > 400 AU denotes severe CAC. RESULTS: Our initial data showed that there were no apparent differences in plasma IL-37 levels among patients with or without mild or moderate CAC. However, IL-37 levels were significantly increased in patients with severe CAC (P < 0.001). Similar results were observed for plasma OPG and hsCRP levels. When IL-37 levels in patients with severe calcification were compared with that in all of the other non-severe CAC groups, it became apparent that there was a significant positive correlation between IL-37 level and severe CAC (r = 0.360, P < 0.001; OR = 1.033) using Spearman's correlation and binary logistic regression analysis. CONCLUSIONS: This study demonstrates that the anti-inflammatory cytokine IL-37 is associated with high coronary calcium levels, suggesting that IL-37 expression may be caused by the activation of inflammation and that IL-37 might become a predictor of severe CAC in the future, which requires further investigation.

Valsartan protects HK-2 cells from contrast media-induced apoptosis by inhibiting endoplasmic reticulum stress.

Contrast-induced acute kidney injury (CI-AKI) is associated with increasing in-hospital and long-term adverse clinical outcomes in high-risk patients undergoing percutaneous coronary intervention (PCI). Contrast media (CM)-induced renal tubular cell apoptosis is reported to participate in this process by activating endoplasmic reticulum (ER) stress. An angiotensin II type 1 receptor (AT1R) antagonist can alleviate ER stress-induced renal apoptosis in streptozotocin (STZ)-induced diabetic mice and can reduce CM-induced renal apoptosis by reducing oxidative stress and reversing the enhancement of bax mRNA and the reduction of bcl-2 mRNA, but the effect of the AT1R blocker on ER stress in the pathogenesis of CI-AKI is still unknown. In this study, we explored the effect of valsartan on meglumine diatrizoate-induced human renal tubular cell apoptosis by measuring changes in ER stress-related biomarkers. The results showed that meglumine diatrizoate caused significant cell apoptosis by up-regulating the expression of ER stress markers, including glucose-regulated protein 78 (GRP78), activating transcription factor 4 (ATF4), CCAAT/enhancer-binding protein-homologous protein (CHOP) and caspase 12, in a time- and dose-dependent manner, which could be alleviated by preincubation with valsartan. In conclusion, valsartan had a potential nephroprotective effect on meglumine diatrizoate-induced renal cell apoptosis by inhibiting ER stress.

Current understanding of coronary artery calcification.

Coronary artery calcification (CAC) is highly prevalent in patients with coronary heart disease (CHD) and is associated with major adverse cardiovascular events. There are two recognized type of CAC-intimal and medial calcification, and each of them have specific risk factors. Several theories about the mechanism of vascular calcification have been put forward, and we currently believe that vascular calcification is an active, regulated process. CAC can usually be found in patients with severe CHD, and this asymptomatic phenomenon make early diagnosis of CAC important. Coronary computed tomographic angiography is the main noninvasive tool to detect calcified lesions. Measurement of coronary artery calcification by scoring is a reasonable metric for cardiovascular risk assessment in asymptomatic adults at intermediate risk. To date, effective medical treatment of CAC has not been identified. Several strategies of percutaneous coronary intervention have been applied to CHD patients with CAC, but with unsatisfactory results. Prognosis of CAC is still a major problem of CHD patients. Thus, more details about the mechanisms of CAC need to be elucidated in order to improve the understanding and treatment of CAC.

IL-35: a potential target for the treatment of atherosclerosis.

The imbalance of anti- inflammatory/pro-inflammatory cytokines plays an important role in the process of atherosclerosis. IL-35 is an anti-inflammatory cytokine comprising the p35 subunit of IL-12 and the subunit Epstein-Barr virus (EBV) -induced gene 3(EBI3). Accumulating evidence showed that IL-35 up-regulates the expression of anti-inflammatory cytokines, induces the generation of CD4 + regulatory T cells, inhibits CD4 + effector T cells response and other target cells activity, and reduces the progression of inflammatory and autoimmune diseases. In addition, it has been found that Ebi3 and p35 strongly coexpressed in human advanced lesions. Therefore, we hypothesize that IL-35 may become a novel target for the treatment of atherosclerosis. Further studies are required to investigate the precise effect and the signaling pathway of IL-35 in atherosclerosis process.

Circulating Th22 and Th9 levels in patients with acute coronary syndrome.

BACKGROUND: CD4+ T helper (Th) cells play critical roles in the development and progression of atherosclerosis and the onset of acute coronary syndromes (ACS, including acute myocardial infarction (AMI) and unstable angina pectoris (UAP)). In addition to Th1, Th2, and Th17 cells, Th22 and Th9 subsets have been identified in humans. In the present study, we investigated whether Th22 cells and Th9 cells are involved in the onset of ACS. METHODS: The frequencies of Th22 and Th9 cells were detected using a flow cytometric analysis and their related cytokine and transcription factor were measured in the AMI, UAP, stable angina pectoris (SAP), and control groups. RESULTS: The results revealed a significant increase in the peripheral Th22 number, AHR expression, and IL-22 levels in patients with ACS compared with those in the SAP and control groups. Although there was no difference in the peripheral Th9 number among the four groups, the PU.1 expression and IL-9 levels were significantly increased in patients with ACS compared with the SAP and control groups. CONCLUSIONS: Circulating Th22 and Th9 type responses may play a potential role in the onset of ACS symptom.

The potential role of IL-37 in atherosclerosis.

Atherosclerosis is an inflammatory disease characterized by extensive lipid deposition and atherosclerotic plaque formation in the intima. Interleukin (IL)-37 is anti-inflammatory cytokine in the IL-1 ligand family. Given that IL-37 plays an important function in the development and progression of inflammatory and autoimmune diseases, it may be associated with the development of atherosclerosis. IL-37, which is normally expressed at low levels in peripheral blood mononuclear cells (PBMC), mainly monocytes, and dendritic cells (DC), is rapidly up-regulated in the inflammatory context, and therefore IL-37 conversely inhibits the production of inflammatory cytokines in PBMC and DC. In addition, IL-37 effectively suppresses the activation of macrophage and DC. It is not controversial that the activation of macrophage and DC and the over-expression of inflammatory cytokines are critical component elements in inflammatory process of atherosclerosis. Therefore, IL-37 may play a protective role in atherosclerosis through inhibition of inflammatory cytokines production and suppression of macrophage and DC activation.

Downregulation of CD4+LAP+ and CD4+CD25+ regulatory T cells in acute coronary syndromes.

BACKGROUND: Regulatory T (Treg) cells play a protective role in atherosclerosis prone models and are related to the onset of acute coronary syndromes (ACS, including non-ST-elevation ACS (NSTEACS) and ST-elevation acute myocardial infarction (STEAMI)). CD4+LAP+ Treg cells are a novel subset of Tregs that have been found to ameliorate atherosclerosis in ApoE(-/-) mice, and these cells also exist in humans. The present study was designed to investigate whether CD4+LAP+ Treg cells are involved in the onset of ACS. METHODS: The frequencies of CD4+LAP+ and CD4+CD25+ Treg cells were detected using flow cytometric analysis, and the plasma IL-10 and TGF- ß 1 levels were measured using an ELISA in 29 stable angina (SA) patients, 30 NSTEACS patients, 27 STEAMI patients, and a control group (30 cases). RESULTS: The results revealed a significant decrease in the frequencies of CD4+LAP+ and CD4+CD25+ Treg cells and in the levels of IL-10 and TGF- ß 1 in patients with ACS compared with those in the SA and control groups. CONCLUSIONS: The decrease in the frequencies of CD4+LAP+ and CD4+CD25+ Treg cells may play a role in the onset of ACS.

Th17 response promotes angiotensin II-induced atherosclerosis.

Vascular wall chronic inflammation plays a critical role in the development and progression of cardiovascular diseases such as atherosclerosis and hypertension. Circulating and tissue angiotensin II can induce potent inflammatory responses in vascular cells and promotes atherosclerosis, whereas the underlying mechanisms remain uncertain. Several data indicated that the upregulation of Th17 response has been found in the local atherosclerotic lesions and circulating lymphocytes in atherosclerosis prone models and the onset of acute coronary syndrome. Evidence from animal models shown that angiotensin II not only induced the Th1 response, but also amplified Th17 response. In addition, angiotensin II-induced hypertension and vascular dysfunction were abolished by blocking Th17/IL-17 effects. Therefore, we hypothesized that Th17 response may play an important role in angiotensin II-induced atherosclerosis.

The role of RANTES as a crucial downstream cytokine in calcineurin-dependent VSMC apoptosis stimulated by INFgamma and CD40L.

Many studies have suggested that VSMC (vascular smooth muscle cell) apoptosis plays a key role in destabilization and rupture of atherosclerotic plaques. Therefore protection for VSMCs from apoptosis is a promising approach to stabilize 'vulnerable' lesions. However, the mechanisms as to why VSMCs in the fibrous cap often appear as profilerated in early stages, but turn apoptotic in advanced stages, are still unknown. In the present study, using RNAi (RNA interference) technology and a CaN (calcineurin) antagonist, the correlation between CaN and RANTES (regulated upon activation, normal T-cell expressed and secreted) in cultured rat apoptotic VSMCs stimulated by IFNgamma (interferon gamma; 20 ng/ml) and CD40L (CD40 ligand; 100 ng/ml) was investigated. RANTES released from VSMCs in each group was measured by ELISA and its mRNA in VSMCs was determined by RT (reverse transcription)-PCR. The total activity and expression of CaN in VSMCs were detected by the zymochemistry method and Western blot analysis respectively. From the results of the present study it can be hypothesized that an elevated CaN concentration in endochylema, by the CD40-CD40L signal pathway, induces VSMC apoptosis accomplished by the overexpression of RANTES. Therefore RANTES is a potential target for treating vulnerable atherosclerotic plaques owing to its crucial downstream regulating role in CaN-dependent VSMC apoptosis.

Downregulation of T helper cell type 3 in patients with acute coronary syndrome.

BACKGROUND AND AIMS: There is an imbalance between Th1 and Th2 in the development and progression of atherosclerosis and in patients with acute coronary syndrome (ACS) including acute myocardial infarction (AMI) and unstable angina. T helper cell type 3 (Th3), which primarily secretes transforming growth factor beta-1 (TGF-beta1), has been shown to inhibit both Th1 and Th2 cells. The present study was designed to investigate whether Th3 cells are involved in plaque destabilization and the onset of ACS. METHODS: Ninety one patients who underwent diagnostic catheterization were classified into four groups (AMI group, unstable angina group, stable angina group and chest pain syndrome group). The cell frequencies of Th1, Th2 and Th3 were detected using flow cytometry, and the concentrations of their related cytokines IFN-gamma, IL-4 and TGF-beta1 were studied by ELISA. RESULTS: Apart from the imbalance between Th1 and Th2, results revealed a significant decrease in peripheral Th3 number and levels of TGF-beta1 in patients with ACS as compared with those in patients with stable angina and chest pain syndrome (p<0.01). CONCLUSIONS: Downregulation of Th3 cells in patients with ACS may play a potential role in plaque destabilization and the onset of ACS.