Jiang-Jiao Xie

The Th17/Treg imbalance in patients with acute coronary syndrome.

Atherosclerosis is a chronic inflammatory disease regulated by T lymphocyte subsets. Recently, CD4+CD25+Foxp3+ regulatory T (Treg) cells and Th17 cells have been described as two distinct subsets from Th1 and Th2 cells and have the opposite effects on autoimmunity. Th17/Treg balance controls inflammation and may be important in the pathogenesis of plaque destabilization and the onset of acute coronary syndrome [ACS, including unstable angina (UA) and acute myocardial infarction (AMI)]. To assess whether this balance was broken in patients with coronary heart disease, we detected Th17/Treg functions on different levels including cell frequencies, related cytokine secretion and key transcription factors in patients with AMI, UA, stable angina (SA) and controls. The results demonstrated that patients with ACS revealed significant increase in peripheral Th17 number, Th17 related cytokines (IL-17, IL-6 and IL-23) and transcription factor (RORgammat) levels and obvious decrease in Treg number, Treg related cytokines (IL-10 and TGF-beta1) and transcription factor (Foxp3) levels as compared with patients with SA and controls. Results indicate that Th17/Treg functional imbalance exists in patients with ACS, suggesting a potential role for Th17/Treg imbalance in plaque destabilization and the onset of ACS.

The Th17/Treg functional imbalance during atherogenesis in ApoE−/− mice

OBJECTIVE Atherosclerosis is a chronic inflammatory disease regulated by T lymphocyte subsets. Recently, CD4(+) CD25(+) Foxp3(+) regulatory T (Treg) cells and Th17 cells have been described as two distinct subsets and have the opposite effects on autoimmunity. Clinical observation has revealed that the Th17/Treg imbalance exists in patients with acute coronary syndrome. We investigated whether the Th17/Treg functional imbalance existed during atherogenesis in ApoE(-/-) mice. METHODS AND RESULTS Th17/Treg functions at different levels including cell frequencies, related cytokine secretion and key transcription factors were investigated comparatively between ApoE(-/-) mice and their age-matched C57BL/6J mice. The results demonstrated that ApoE(-/-) mice revealed significantly increased secretion of Th17 related cytokines (IL-17 and IL-6) and expression of transcription factor (RORgammat) levels and obviously decreased number in Treg cells, secretion of Treg related cytokines (TGF-beta(1)) and expression of transcription factor (Foxp3) levels as compared with age-matched C57BL/6J mice. Th17 related mediators reached their maximum expression values at the early stage (8-16weeks of age) in ApoE(-/-) mice, and then followed by continuous depression of their expression levels. Meanwhile, the expression of Treg related mediators was much lower in ApoE(-/-) mice than in their age-matched wild-type littermates. CONCLUSIONS Th17/Treg functional imbalance exists during atherogenesis in ApoE(-/-) mice, suggesting a potential role of Th17/Treg imbalance in the formation and progression of atherosclerosis.

Inhibition of IL-17A in atherosclerosis

OBJECTIVE To determine the effects of interleukin (IL)-17A inhibition on experimental atherosclerosis. METHODS AND RESULTS ApoE(-/-) mice were treated with either rat anti-mouse IL-17A, mouse anti-mouse IL-17A or isotype-matched control antibodies for 12 weeks (n=8-10 per group). Ldlr(-/-) mice were transplanted with IL-17A-deficient or wild type bone marrow (n=8 per group). Rat anti-mouse IL-17A treatment obviously reduced plaque size by 43% (p<0.01) without evidence of reduced IL-17A signaling. In contrast, mouse anti-mouse IL-17A treatment and IL-17A deficiency in bone marrow cells did not alter lesion size despite significant reduction of IL-17A production. CONCLUSIONS Inhibition of IL-17A signaling does not alter lesion development in Th1-biased C57BL/6 ApoE(-/-) and Ldlr(-/-) mice with already low levels of IL-17A production. Alteration of lesion development after repeated injections of rat anti-mouse IL-17A antibody in ApoE(-/-) mice could not be attributed to blockade of IL-17A signaling.

Defective Circulating CD4+CD25+Foxp3+CD127low Regulatory T-cells in Patients with Chronic Heart Failure

Aims: Increasing evidences confirm the role of immune activation in the pathogenesis of chronic heart failure (CHF). Regulatory T cells appear central to the control of immune homeostasis. We assessed the hypothesis that the circulating frequency and function of CD4+CD25+ Foxp3+CD127low T regulatory cells (Tregs) would be deranged in patients with CHF. Methods: Ninety-nine CHF patients due to non-ischemic (NIHF) or ischemic etiology (IHF) and 24 control donors were enrolled in the study. Frequency of circulating Tregs was evaluated by flow cytometry. Foxp3 in peripheral blood mononuclear cells (PBMCs) was assayed at the mRNA level by real-time PCR. Functional properties of Tregs to suppress proliferation and pro-inflammatory cytokines secretion of activated CD4+CD25- T cells were measured by proliferation assay and ELISA. Results: The results demonstrated that CHF patients had significantly lower frequency of circulating Tregs and reduced Foxp3 expression in PBMCs compared with control donors. Moreover, Tregs from CHF patients showed compromised function to suppress CD4+CD25- T cells proliferation and pro-inflammatory cytokines secretion. A similar pattern with reduced Tregs frequency and compromised function was found in both NIHF and IHF patients. Correlation analysis suggested that Tregs frequency and function positively correlated with LVEF, whereas negatively correlated with LVEDD and NT-proBNP in patients with CHF. Conclusions: Our data are the first to demonstrate that frequencies of circulating Tregs in patients with CHF are reduced and their suppressive function compromised independently of the etiology. Defective Tregs may be an underlying mechanism of immune activation in CHF patients.

Relationship between plasma inflammatory markers and plaque fibrous cap thickness determined by intravascular optical coherence tomography

Objective The purpose of this study was to evaluate the relationship between human plaque fibrous cap thickness detected by intravascular optical coherence tomography (OCT) and the plasma levels of inflammatory factors in patients with coronary artery disease (CAD). Methods and Results OCT was used to measure the fibrous cap thickness of coronary artery atherosclerotic plaques in patients with acute myocardial infarction (AMI), unstable angina pectoris (UAP) and stable angina pectoris (SAP). Plasma levels of inflammatory factors including highly sensitive C-reactive protein (hs-CRP), IL-18 and tumour necrosis factor alpha (TNFα) were detected by ELISA, and peripheral white blood cell (WBC) counts were performed. The results demonstrated that the plasma levels of inflammatory factors and WBC count were correlated inversely with fibrous cap thickness (r = −0.775 for hs-CRP, r = −0.593 for IL-18, r = −0.60 for TNFα and r = −0.356 for WBC count). Patients with cap thickness less than 65 μm (defined to be thin cap fibroatheromas; TCFA) had higher plasma levels of inflammatory factors as well as WBC counts than those with thicker fibrous caps. Receiver operator characteristic (ROC) curves for hs-CRP, IL-18, TNFα and WBC count, which displayed the capability of prediction about TCFA, showed the area under the curves were 0.95, 0.86, 0.79 and 0.70 (p<0.05), respectively. ROC curve analysis confirmed that an hs-CRP cut-off at 1.66 mg/l would detect TCFA with a sensitivity of 96% and a specificity of 90%, and was the strongest independent predictor of TCFA. Conclusion There is an inverse linear correlation between fibrous cap thickness and plasma levels of inflammatory markers. The plasma hs-CRP concentration is the strongest independent predictor of TCFA.

Atorvastatin Modulates Th1/Th2 Response in Patients With Chronic Heart Failure

BACKGROUND The T-helper (Th)1/Th2 imbalance has been demonstrated to be involved in chronic heart failure (CHF). We sought to determine whether atorvastatin exhibited any effect on CHF through modulating the Th1/Th2 response. METHODS AND RESULTS We measured serum concentrations of interleukin (IL)-12, -18, interferon (IFN)-gamma, IL-4, and IL-10 from 20 controls and 72 patients with nonischemic CHF by enzyme-linked immunosorbent assay. To investigate the effect of atorvastatin in vivo, CHF patients were either classified into a usual therapy group (n = 35) or usual therapy plus atorvastatin (10 mg/day) group (n = 37). Patient serum levels of IFN-gamma and IL-4 were measured at time of admission and 2 weeks after treatment. Peripheral blood mononuclear cells from patients of CHF group were cultured in the presence or absence of atorvastatin (0, 0.4, 1, and 4 micromol/L) in vitro, and IFN-gamma and IL-4 levels were detected. Serum levels of IL-12, IL-18, and IFN-gamma were significantly higher in the CHF group than in the control group. The levels of IFN-gamma and the ratios of IFN-gamma:IL-4 were significantly decreased with atorvastatin treatment both in vivo and in vitro, whereas levels of IL-4 did not differ significantly. CONCLUSIONS Th1 polarization exists in patients with CHF, and atorvastatin can modulate the Th1/Th2 response through inhibiting Th1 cytokine production.

MicroRNA-21 negatively regulates Treg cells through a TGF-β1/Smad-independent pathway in patients with coronary heart disease.

Background: CD4+CD25+FoxP3+ regulatory T cells (Treg cells) play a protective role against the development and progression of the inflammatory disease atherosclerosis (AS). MicroRNA-21 (miR-21) is expressed in Treg cells and is up-regulated in the context of AS and other inflammatory diseases. Aims: This study aimed to determine the role of miR-21 in Treg cell regulation and gene expression during the development of AS in patients with coronary heart disease (CHD). Methods and Results: MiR-21 expression in peripheral blood mononuclear cells (PBMCs) was significantly up-regulated in patients with CHD (acute myocardial infarction (AMI) group, n=24; unstable angina (UA) group, n=21; stable angina (SA) group, n=24) compared with patients with chest pain syndrome (CPS, n=27), and miR-21 expression showed an increasing trend from SA to UA to AMI patients. Moreover, flow cytometry analysis indicated that the frequencies of circulating Treg cells decreased in a manner proportionate opposite with the level of miR-21. Quantitative real-time PCR (qRT-PCR) revealed a decrease in mRNA expression of forkhead box P3 (foxp3), transforming cell growth factor beta 1(TGF-β1) and smad7 (a known target gene of miR-21). ELISA analysis revealed a decrease in TGF-β1 secreted into the plasma. In addition, we transfected PBMCs with a miRNA negative control (NS-m), a miR-21 mimic (miR-21-m), a miRNA inhibitor negative control (NS-i), or a miR-21 inhibitor(miR-21-i). Up-regulation of miR-21 decreased the frequency of circulating Treg cells, decreased the expression levels of foxp3, TGF-β1 and smad7, and decreased the amount of TGF-β1 secreted into the plasma. Consistent with these observations, miR-21 down-regulation increased the frequency of circulating Treg cells, increased the expression of foxp3, TGF-β1 and smad7, and increased the amount of TGF-β1 secreted into the plasma. Conclusions: Because the smad7 expression pattern was similar to that of TGF-β, our study suggests that miR-21 can negatively regulate the frequency of circulating Treg cells through a TGF-β1/smad-independent signaling pathway in PBMCs.

Molecular mechanisms of felodipine suppressing atherosclerosis in high-cholesterol-diet apolipoprotein E-knockout mice.

Oxidative stress and inflammation processes are key components of atherosclerosis, from fatty streak formation to plaque rupture and thrombosis. Evidence has revealed that calcium-channel blockers (CCB) could retard atherogenesis, but the exact mechanisms have not been fully elucidated. The present study was undertaken to investigate the potential effects and molecular mechanisms of the CCB felodipine on the process of atherosclerosis in high-cholesterol-diet (HCD) apolipoprotein E-knockout (ApoE KO) mice. Adult male ApoE KO mice were given a normal diet (ND) or HCD and were randomized to no treatment or felodipine (5 mg / kg per day for 12 weeks). The ApoE KO mice with HCD were associated with a marked increase in plasma lipid levels, atherosclerotic lesion area, and the expressions of NADPH oxidase subunits (p47phox and Rac-1), nuclear factor-κB (NF-κB) in nucleus, phosphor-inhibitors of κB (p-IκB), tumor necrosis-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), and vascular cell-adhesion molecule-1 (VCAM-1). These changes were suppressed in mice that were treated with felodipine (5 mg/kg per day for 12 weeks) concomitant with HCD administration, with no significant change in systolic blood pressure and plasma lipid levels. The results suggest that felodipine can attenuate atherosclerosis, and this effect is partly related to inhibition of oxidative stress and inflammatory signal-transduction pathways, which lead to decreases in the expression of inflammatory cytokines.

Effects of welding parameters on mechanical properties and microstructure of resistance spot welded DP600 joints

Abstract This paper experimentally investigates the effects of welding parameters including electrode force, welding current and welding time on the mechanical properties and microstructure of resistance spot welded DP600 joints. The experimental results show that there exists an optimum value for each set of welding parameters that can maximise the mechanical properties and welding nugget size. The welding nugget size is a key factor controlling the mechanical properties of resistance spot welded DP600 joints; there is a relationship among welding nugget size, tensile shear load and failure energy. A larger welding nugget size leads to a greater probability of pullout failure. In addition, welding parameters also affect the microstructure, grain size, crack initiation and microhardness of resistance spot welded DP600 joints.

Impaired Thymic Export and Apoptosis Contribute to Regulatory T-Cell Defects in Patients with Chronic Heart Failure

Objective Animal studies suggest that regulatory T (Treg) cells play a beneficial role in ventricular remodeling and our previous data have demonstrated defects of Treg cells in patients with chronic heart failure (CHF). However, the mechanisms behind Treg-cell defects remained unknown. We here sought to elucidate the mechanism of Treg-cell defects in CHF patients. Methods and Results We performed flow cytometry analysis and demonstrated reduced numbers of peripheral blood CD4+CD25+FOXP3+CD45RO−CD45RA+ naïve Treg (nTreg) cells and CD4+CD25+FOXP3+CD45RO+CD45RA− memory Treg (mTreg) cells in CHF patients as compared with non-CHF controls. Moreover, the nTreg/mTreg ratio (p<0.01), CD4+CD25+FOXP3+CD45RO− CD45RA+CD31+ recent thymic emigrant Treg cell (RTE-Treg) frequency (p<0.01), and T-cell receptor excision circle levels in Treg cells (p<0.01) were lower in CHF patients than in non-CHF controls. Combined annexin-V and 7-AAD staining showed that peripheral Treg cells from CHF patients exhibited increased spontaneous apoptosis and were more prone to interleukin (IL)-2 deprivation- and CD95 ligand-mediated apoptosis than those from non-CHF individuals. Furthermore, analyses by both flow cytometry and real-time polymerase chain reaction showed that Treg-cell frequency in the mediastinal lymph nodes or Foxp3 expression in hearts of CHF patients was no higher than that of the non-CHF controls. Conclusion Our data suggested that the Treg-cell defects of CHF patients were likely caused by decreased thymic output of nascent Treg cells and increased susceptibility to apoptosis in the periphery.