IL-1ß knockdown inhibits cigarette smoke extract-induced inflammation and apoptosis in vascular smooth muscle cells.

OBJECTIVE: This study was aimed to investigate the role of interleukin-1ß (IL-1ß) in cigarette smoke extract (CSE)-induced apoptosis in vascular smooth muscle cells and the underlying mechanism in a rat derived cell line. METHODS: Rat thoracic aortic smooth muscle cells (A7r5) were divided into six groups including control, CSE (model), CSE+ overexpression empty vector (OvExp-EV), CSE+IL-1ß knockdown (KD), and CSE+ IL-1ß knockdown empty vector (KD-EV). The mRNA expression levels of IL-1ß and pregnancy-associated plasma protein A (PAPP-A) were detected by quantitative polymerase chain reaction (qPCR). The apoptosis of A7r5 cells was detected by flow cytometry. The expression levels of inflammatory mediators (TNFα, IL-6 and IL-8) and apoptotic proteins (Bax and Bcl-2) were determined by western blot. RESULTS: CSE induced significant apoptosis in vascular smooth muscle cells (P < 0.01) and elevated the mRNA levels of IL-1ß and PAPP-A (P < 0.01). CSE administration increased protein expression of Bax, TNF-α, IL-6, and IL-8, with significantly reduced Bcl-2 expression (P < 0.01). IL-1ß knockdown significantly decreased cell apoptosis via regulating the expression of these proteins (P < 0.05 or P < 0.01). CONCLUSION: IL-1ß is involved in CSE-induced PAPP-A expression and apoptosis in vascular smooth muscle cells, which might be considered as a target for preventing of cardiovascular diseases caused by cigarette smoking.

IL-17A facilitates platelet function through the ERK2 signaling pathway in patients with acute coronary syndrome.

BACKGROUND: Platelet aggregation mediated by inflammation played a critical role in the development of coronary heart diseases (CHD). Our previous clinical researches showed that Th17 cells and their characteristic cytokine IL-17A were associated with the plaque destabilization in patients with acute coronary syndrome (ACS). However, the potent effect of IL-17A on platelets-induced atherothrombosis remains unknown. METHODS AND RESULTS: In this study, we detected the plasma IL-17A levels and platelet aggregation in patients with stable angina (SA), unstable angina (UA), acute myocardial infarction (AMI) and chest pain syndrome (CPS). In addition, the markers of platelet activation (CD62P/PAC-1) and the mitogen-activated protein kinases (MAPKs) pathway were detected in platelets from ACS patients. We found that plasma IL-17A levels and platelet aggregation in patients with ACS (UA and AMI) were significantly higher than patients with SA and CPS, and the plasma IL-17A levels were positively correlated with the platelet aggregation (R = 0.47, P<0.01). In addition, in patients with ACS, the platelet aggregation, CD62P/PAC-1 and the phosphorylation of ERK2 signaling pathway were obviously elevated in platelets pre-stimulated with IL-17A in vitro. Furthermore, the specific inhibitor of ERK2 could attenuate platelet aggregation and activation triggered by IL-17A. CONCLUSION: Our experiment firstly proved that IL-17A could promote platelet function in patients with ACS via activating platelets ERK2 signaling pathway and may provide a novel target for antiplatelet therapies in CHD.

[Myocardial autoimmune response induced by myosin activate T lymphocytes].

AIM: To investigate whether myosin activated-T lymphocytes induce myocardial autoimmune response. METHODS: Dendritic cells and T lymphocytes were isolated and purified from spleens of Lewis rats. After cocultured in the absence or presence of cardiac myosin (20 mug/mL), the sensitized or unsensitized T lymphocytes were transferred into the naive syngeneic Lewis rats by a single tail vein infusion, respectively. The recipient rats were killed on the third day, at the first and fourth week and then the histopathological changes of the rats were observed. RESULTS: T lymphocyte infiltration was observed on the third day. It reached the peak with occasional myocardium necrosis at the first weekend. T cell infiltration distinctly lessened at the fourth weekend. No T lymphocyte infiltration was found in kidney, liver, lung, and brain. T lymphocyte infiltration wad not detected in the heart of the transferred unsensitized T lymphocytes of the rats. CONCLUSION: Myocardial autoimmune response can be induced by myosin activated T lymphocytes.

Adipose tissue stromal cells transplantation in rats of acute myocardial infarction.

OBJECTIVE: This study was to investigate the proliferation and differentiation of rat adipose stromal cells when implanted into ischemic myocardium and the improvement of heart function. METHODS: Sprague-Dawley rat adipose tissue was digested with collagenase type I solution and adipose stromal cells were derived by culture. The cells' surface phenotype was examined by flow cytometry. Adipose stromal cells labeled with 4'6-diamidino-2-phenylindole (adipose stromal cells group) or Dulbecco's modified Eagle medium (control group) was transplanted into the ischemic myocardium, which was produced by ligation of left descending branch of coronary artery. At 1 and 4 weeks after transplantation, specimens were acquired from infarcted area and also echocardiography was done to detect the effects on heart function. Then, cell morphology and capillary density were measured, and vascular endothelial growth factor expression levels were assayed by reverse transcription-PCR and enzyme-linked immunosorbent assay. RESULT: Adipose stromal cells derived by culture expressed CD44 and CD90 but not CD31 or CD45. Adipose stromal cells were alive at 1 and 4 weeks after transplantation and had a trend toward differentiation into vascular endothelial cells. The number of capillary vessels in peri-infarct area in adipose stromal cells group increased significantly compared with control group (P<0.01). The levels of vascular endothelial growth factor mRNA and protein expression at 1 week increased significantly in adipose stromal cells group compared with control group (P<0.01). Left ventricular function, including ejection fraction and fractional shortening, was higher in adipose stromal cells group when compared with control group at 4 weeks (P<0.01). CONCLUSION: Adipose stromal cells transplantation can accelerate angiogenesis in infarcted area after rat myocardial infarction and can improve heart function.

The dynamic change of TGF-beta1 in the myocardial remodeling of rat after myocardial infarction.

To observe the dynamic changes of the TGF-beta1 expressed in the infarct and non-infarcted region of rat heart during the ventricular remodeling (day 3, 7, 28, 180), myocardial infarction rat model was made and relationship between the cytokine and indicator of myocardial remodeling was analyzed. After the detection of hemodynamic parameter was performed by the Powerlab devices, the size of myocardial infarction and the morphology change was detected by TTC and HE, respectively. The relative levels of mRNA of TGF- beta1, collagen type I, III, and fetal gene beta-MHC were detected by RT-PCR. The distribution of TGF- beta1 protein in the myocardium was detected by immunohistochemistry. The results showed that the size of infarction was higher than that of the sham operated groups in the infarcted group (44.5 +/- 0.5 vs 0). The difference in hemodynamic parameters between the infarcted group and sham operated group was significant (P < 0.01). HE staining showed that inflammatory cells were accumulated in the infarcted region at the beginning of the 3rd day, which lasted 4 weeks. Then, it decreased gradually. beta-MHC in the non-infarcted region rose from the 3rd day, reaching its peak at the 4th week, and it decreased gradually. The ratio of the collagen type I/III showed similar changes as compared with the sham operated groups (P < 0.01). And the relative mRNA levels in the non-infarcted group were significantly higher than that in the infarcted and sham operated group (P < 0.01) at day 180. Linear regression analysis indicated that the TGF-beta1 was positively correlated with the ventricular remodeling. It was concluded that the cytokine TGF-beta1 participates in the process of the myocardial remodeling, which could be a strategy in the interference of myocardial remodeling.

[The significance of Th1/Th2 function imbalance in patients with post-infarction cardiac insufficiency].

OBJECTIVE: To study the significance of Th1/Th2 function imbalance in patients with post-infarction cardiac insufficiency. METHODS: Forty-three MI (myocardial infarction) patients were divided into 2 groups one month after the onset according to the New York Heart Association (NYHA) classification system: group MI 1 (I, II) 25 patients and group MI 2 (III, IV) 18 patients. At the same time, the heart function was evaluated by two-dimensional echocardiography. Peripheral blood mononuclear cells (PBMCs) were collected from these patients. Cytokine-producing CD4 + T cells were quantified by 3-color flow cytometry after being stimulated with phorbol myristate acetate (PMA) and ionomycin. After being stimulated with PHA, the levels of IFN-gamma and IL-4 in culture supernatants were measured by ELISA. RESULTS: The frequencies of IFN-gamma-producing T cells were found to be significantly higher in group MI 2 (16.8%) than that in group MI 1 (13.1%). There was no significant difference on the frequencies of IL-4-producing peripheral T cells between the two groups. The IFN-gamma level and the ratios of IFN-gamma/IL-4 in group MI 2 were significantly higher than those in group MI 1, while there was no significant difference in IL-4 levels between the two groups. CONCLUSIONS: The Th-cell function was associated with heart function in post MI patients. The up-regulation of Th1 cell function was consistent with poor heart function, suggesting that Th1/Th2 cell function imbalance may participate in ventricular remodelling after MI.

[Effects of early treatment with metoprolol on myocardial inflammatory cytokine expression and heart function in rats with acute myocardial infarction].

OBJECTIVE: The aim of study was to explore the effects of early beta-adrenergic blockade-metoprolol treatment on myocardial inflammatory cytokine expression and heart function in rats after acute myocardial infarction (AMI). METHODS: The therapeutic effects of metoprolol on myocardial inflammation and heart function up to 4 weeks (according to the protocol of CCS-2) were studied by the rat model of AMI. Myocardial inflammation was examined by taking account of the number of lymphocytes infiltrated in the myocardium and analyzing the myocardial cytokine production including the pro-inflammatory cytokines: interleukin (IL)-1beta, 6 and tumor necrosis factor (TNF)-alpha and the anti-inflammatory cytokine: IL-10. Echocardiography was used to evaluate heart function. RESULTS: The levels of TNF-alpha, IL-1beta, IL-6 and IL-10 in AMI group were markedly elevated compared to sham rats (P < 0.01) and the cytokines principally excreted by cardiac myocytes. After 4 weeks therapy, metoprolol reduced the production of TNF-alpha and IL-1beta and increased IL-10 levels (P < 0.05) in cardiac myocytes, but had no effect on the number of lymphocytes infiltrated in myocardium. Echocardiography showed that metoprolol markedly improved left heart function (P < 0.05). CONCLUSION: Early metoprolol treatment can improve heart function and myocardial inflammatory cytokine expression after AMI. One immunopharmacologic mechanism underlying the beneficial effects of beta-adrenergic blockade may involve the attenuation of pro-inflammatory cytokines and the increase of anti-inflammatory cytokine levels in cardiac myocytes.

TH1/TH2 functional imbalance after acute myocardial infarction: coronary arterial inflammation or myocardial inflammation.

OBJECTIVES: The study clarified whether the T-helper (Th)1/Th2 imbalance existed only in coronary arterial inflammation or in both coronary arterial inflammation and myocardial inflammation and explored the significance of the imbalance of Th1/Th2 function after acute myocardial infarction (AMI). BACKGROUND: There are two different inflammatory processes in patients with AMI: the coronary arterial inflammation that leads to the pathogenesis of AMI and the myocardial inflammation after AMI that leads to ventricular remodeling, which are positively and negatively regulated by Th1 and Th2 lymphocytes, respectively. METHODS: Peripheral blood mononuclear cells from 33 AMI patients, 22 unstable angina (UA) patients and splenocytes from 35 AMI Wistar rats were collected. Cytokine-producing Th cells were ambulatorily monitored by 3-color flow cytometry. Interferon (IFN)-gamma and interleukin (IL)-4 mRNA in the rat myocardium and chemokine receptors CCR3,CCR5 and CXCR3 mRNA on the surface of rat T-lymphocytes after AMI were measured by RT-PCR. RESULTS: IFN-gamma-producing T-cells significantly increased in patients with AMI and UA within 24 hours after the onset of symptom. The high ratio of IFN-gamma-producing T-cells recovered 1 week after the onset in UA patients, while it could be examined 1 week and even 1 month after the onset in AMI patients. The up-regulation of Th1 cell function is consistent with bad heart function. There was no significant difference on the frequencies of IL-4-producing T-cells between each group. 1 week, 2 weeks and 1 month after AMI, IFN-gamma mRNA increased in the myocardium of rats, but there was no significant change on global Th cell functions. CONCLUSIONS: Th1/Th2 functional imbalance exists in both coronary arterial inflammation and myocardial inflammation processes. The up-regulation of Th1 cell-functions may participate in the immune-mediated ventricular remodeling after AMI.

Simvastatin regulates myocardial cytokine expression and improves ventricular remodeling in rats after acute myocardial infarction.

PURPOSE: Studies have showed that inflammatory cytokines were involved in the process of left ventricular (LV) remodeling after acute myocardial infarction (AMI), anti-inflammation treatment ameliorated LV remodeling and improved cardiac performance. Hydroxymethylglutary coenzyme A reductase inhibition (statins) could affect the expression of inflammatory cytokines. We hypothesized that statins have beneficial effects on early LV remodeling and cardiac performance in rats with AMI by modulating the production of inflammatory cytokines. METHODS: Rats with AMI were treated with placebo or simvastatin (gastric gavage) for 4 weeks. The pro-inflammatory cytokines: tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6 and the anti-inflammatory cytokine: IL-10 excreted by cardiac myocytes was examined. Echocardiography, hemodynamics and collagen type I production were measured to evaluate LV remodeling and cardiac function. RESULTS: The mRNA expression and protein production of TNF-alpha, IL-1beta, IL-6 and IL-10 in AMI group were significantly elevated compared with sham rats. Simvastatin markedly attenuated the production of TNF-alpha, IL-1beta, IL-6 and increased IL-10 levels in the noninfarcted and infarcted regions, reduced collagen deposition in the noninfarcted myocardium and improved left ventricular function. However simvastatin did not alter plasma lipids. CONCLUSIONS: Simvastatin ameliorates early LV remodeling and improve cardiac function after AMI. Simultaneously, it decreased pro-inflammatory and increased anti-inflammatory cytokines, which suggests, but does not prove, a causal relationship independent of plasma lipid-lowering effects.