[show abstract][hide abstract] ABSTRACT: BACKGROUND: Both hyperglycaemia and dendritic cells (DCs) play causative roles in atherosclerosis. However, whether they interact in atherosclerosis remains uncertain. Therefore, we examined whether high glucose could regulate the expression of scavenger receptors responsible for oxidised low-density lipoprotein (oxLDL) uptake in DCs, a critical step in atherogenesis. In addition, we investigated the impact of glucose on DC maturation regarding changes in phenotype and cytokine secretion. METHODS: Immature DCs were cultured with different concentrations of glucose (5.5 mmol/L, 15 mmol/L, 30 mmol/L) in the absence or presence of N-acetylcysteine (NAC), SB203580 or Bay11-7082 for 24 hours. We used 30 mmol/L mannitol as a high-osmolarity control treatment. The expression of the scavenger receptors SR-A, CD36 and LOX-1 was determined by real-time PCR and western blot analysis. Furthermore, DCs were incubated with DiI-labelled oxLDL. The DiI-oxLDL-incorporated fraction was investigated by flow cytometry analysis. The intracellular production of ROS in DCs was measured by dichlorodihydrofluorescein (DCF) fluorescence using confocal microscopy. Finally, flow cytometry analysis was used to investigate immunophenotypic protein expression (CD83 and CD86). Supernatant cytokine measurements were used for immune function assays. RESULTS: The incubation of DCs with glucose enhanced, in a dose-dependent manner, the gene and protein expression of SR-A, CD36 and LOX-1. This effect was partially abolished by NAC, SB203580 and Bay11-7082. Incubation of DCs with mannitol (30 mmol/L) did not enhance these scavenger receptors' expression. High glucose upregulated the production of ROS and expression of p38 MAPK in DCs. NAC partially reversed p38 MAPK upregulation. High glucose increased the oxLDL-uptake capacity of DCs. Blockage of the scavenger receptors SR-A and CD36 reduced oxLDL uptake, but blockage of LOX-1 did not. Furthermore, high-glucose (15 mmol/L or 30 mmol/L) treatment increased CD86 and CD83 in DCs. High glucose also increased IL-6 and IL-12 secretion and decreased IL-10 secretion. CONCLUSION: High glucose can increase the expression of the scavenger receptors SR-A, CD36 and LOX-1, which can increase the oxLDL-uptake capacity of DCs. High glucose induces a proinflammatory cytokine profile in human DCs, leading to DC maturation. These results support the hypothesis that atherosclerosis is aggravated by hyperglycaemia-induced DC activation and oxLDL uptake.
[show abstract][hide abstract] ABSTRACT: The angiotensin II receptor-1 blockers have generally been shown to have antiatherogenic effects, and dendritic cells (DCs) are the most efficient antigen presenting cells that play an active role in the development of atherosclerosis through inflammatory-immune responses. Here, we tested the hypothesis that the antiatherogenic effect of losartan, the first angiotensin II receptor-1 blockers, might partly be mediated by attenuating DCs maturation. In this study, we showed that oxidized low-density lipoprotein (oxLDL) and angiotensin II (Ang II) could induce the maturation of human monocyte-derived DCs, stimulate CD83, HLA-DR expressions and IL-12, interferon-gamma secretions and increase the capacity of DCs to stimulate T-cell proliferation, which were suppressed by losartan. OxLDL could promote the autocrine secretion of Ang II by DCs and upregulate the expressions of 3 scavenger receptors SR-A, CD36, and LOX-1. Losartan reduced oxLDL-induced LOX-1 expression but not SR-A and CD36 expressions. Ang II could only upregulate the LOX-1 expression, which was reduced by losartan. OxLDL- and Ang II-induced upregulation of CD83 and secretion of IL-12 were all attenuated by LOX-1 neutralizing antibody. In conclusion, losartan could attenuate the oxLDL- and Ang II-induced immune maturation of human monocyte-derived DCs partly through downregulation of the LOX-1 expression.
Journal of cardiovascular pharmacology 04/2012; 60(2):133-9. · 2.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: It has been shown that dendritic cells (DCs) and fractalkine play a role in accelerating progression of the inflamed atherosclerotic lesions and plaque rupture. We evaluated the numbers and functional changes of DCs and its subsets in human type 2 diabetes with or without unstable angina pectoris (UAP).
The study population consisted of 39 diabetic patients (DM:18 without CAD; DM + UAP: 21 with UAP), 18 non-diabetic UAP patients (UAP), and 15 healthy control (Normal). Peripheral blood DCs and its subsets were measured by three color flow cytometry. Serum levels of fractalkine, IL-12, and IFN-α were also measured. The functional status of the monocyte-derived DCs was analyzed by flow cytometry and allogeneic mixed T lymphocytes reaction.
The percent and absolute numbers of DCs and mDC within the total leukocyte population was similar for Normal and DM, while significantly lower in DM + UAP. pDC numbers were not significantly altered. Serum fractalkine in DM + UAP was highest among the four groups (p = 0.04 vs. UAP, p = 0.0003 vs. DM, p < 0.0001 vs. Normal). Circulating mDC inversely correlated with serum fractalkine (r = -0.268, p = 0.01) level. Compared with DM and UAP, the costimulatory molecules CD86 and proliferation of T cells stimulated by DCs were significantly increased in DM + UAP group.
Our study suggested that increases in the fractalkine level and the number and functional changes of blood DCs might contribute to diabetic coronary atherosclerosis and plaque destabilization.
[show abstract][hide abstract] ABSTRACT: To compare the efficacy and feasibility between intracoronary and hypodermic injection of granulocyte colony-stimulating factor (G-CSF) on improving cardiac function in a Swine model of chronic myocardial ischemia.
Eighteen Swine underwent placement of ameroid constrictor on left circumflex coronary artery. The presence of myocardial ischemia was verified at four weeks after the operation, and the animals were then randomly assigned into three groups (n = 6 each): (1) administration of vehicle (control), (2) hypodermic injection of G-CSF (5 microgxkg(-1)x;d(-1)) for five days (IH), and (3) intracoronary injection of a bonus G-CSF (60 microg/kg) (IC). Coronary angiogram, cardiac MRI, and (18)F-FDG-SPECT/(99m)Tc-SPECT (DISA-SPECT) measurements were performed at pre-administration and at 4 weeks post administration. Global heart function such as left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVSDV) and left ventricular ejection fraction (LVEF), myocardial perfusion, myocardial viability and myocardial infarct area were evaluated. Myocardial vWF, Bcl-2 and Bax expressions were detected by Western blot and RT-PCR.
MRI data showed that left ventricular dilation and dysfunction were similarly prevented in IH and IC G-CSF treated animals at eight weeks after the operation. SPECT revealed that both IH and IC G-CSF equally improved the regional contractility of chronic myocardial ischemia and increased myocardial viability. Myocardial infarct size was also reduced after both G-CSF treatments as detected by MRI. Intracoronary injection of G-CSF did not lead to angiogenesis in other organs. G-CSF treatments were also associated with a significant reduction in myocardial apoptosis and significant increase in angiogenesis.
Both intracoronary and hypodermic injection of G-CSF were safe and feasible and could equally improve cardiac function and increase angiogenesis in this Swine model of chronic myocardial ischemia.
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 08/2009; 37(8):685-91.
[show abstract][hide abstract] ABSTRACT: Dendritic cells an hyperinsulinemia are both implicated in the pathogenesis of atherosclerosis. The aim of this study is to explore the effect of high concentration of insulin on the maturation of monocyte-derived dendritic cells (MoDCs) and related signal transduction pathways.
Human monocytes were purified (over 98%) using Anti-CD14 micro-beads and cultured for 5 days with DC Cellgro medium containing rhGM-CSF (100 microg/L) and rhIL-4 (20 microg/L). Immature DC were then incubated with insulin of various concentrations (0, 1, 10, 100 nmol/L) for 24 hours in the presence or absence of LY294002 (PI3K inhibitor) or PD98059 (MAPK inhibitor). Immunophenotypic expression of CD86 and CD83 were detected using flow cytometry. Endocytosis function of the MoDCs was evaluated using FITC-Dextran and MoDCs secretion IL-12, IFN-gamma and TNF-alpha were measured by ELISA.
Insulin induced significantly higher CD83 and CD86 expressions on MoDCs in a dose-dependent manner. The endocytosis function of MoDCs were significantly inhibited and cytokine secretions of IL-12, IFN-gamma and TNF-alpha significantly increased by 10 nmol/L and 100 nmol/L insulin. These effects could be blocked by the LY294002 and PD98059.
Hyperinsulinemia contributed to atherosclerosis via stimulating immune maturation of MoDCs via both PI3K and MAPK pathways.
Zhonghua xin xue guan bing za zhi [Chinese journal of cardiovascular diseases] 01/2008; 35(12):1151-4.