Xiao Ping Ji

Oral rapamycin attenuates inflammation and enhances stability of atherosclerotic plaques in rabbits independent of serum lipid levels.

Background and purpose:  Atherosclerotic plaque rupture and thrombosis are the main cause of acute coronary syndrome. The study was aimed to test the hypothesis that oral administration of rapamycin may attenuate inflammation, inhibit progression and enhance stability of atherosclerotic plaques.

Traditional Chinese medication Tongxinluo dose-dependently enhances stability of vulnerable plaques: a comparison with a high-dose simvastatin therapy

This study was carried out to test the hypothesis that Tongxinluo (TXL) as a Chinese herbal medicine enhances stability of vulnerable plaque dose dependently via lipid-lowering and anti-inflammation effects, similar to a high-dose simvastatin therapy. After abdominal aortic balloon injury, 75 rabbits were fed a 1% cholesterol diet for 10 wk and were then divided into five groups for 8-wk treatment: control group, low-dose TXL group, moderate-dose TXL group, high-dose TXL group, and high-dose simvastatin group. At the end of week 16, an adenovirus containing p53 was injected into the abdominal aortic plaques. Two weeks later, plaque rupture was induced by pharmacological triggering. The incidence of plaque rupture in all treatment groups (14.3%, 7.1%, 7.7%, and 7.1%) was significantly lower than that in control group (73.3%; P>0.01). TXL dose-dependently lowered serum lipid levels and inhibited systemic inflammation. Corrected acoustic intensity and fibrous cap thickness of the aortic plaques were significantly increased, whereas plaque area, plaque burden, vulnerable index, and expression of oxidized low-density lipoprotein (ox-LDL) receptor 1, matrix metalloproteinase 1 (MMP-1), MMP-3, tissue inhibitor of MMP 1, and NF-kappaB in plaques were markedly reduced in all treatment groups when compared with the control group. Similar to high-dose simvastatin group, high-dose TXL group exhibited a low serum level of low-density lipoprotein cholesterol and ox-LDL, a low expression level of systemic and local inflammatory factors and a low plaque vulnerability index, with no differences in the incidence of plaque rupture among all treatment groups. TXL dose-dependently enhances the stability of vulnerable plaques and prevents plaques from rupture. Simvastatin and TXL offer similar protection in terms of lipid-lowering, anti-inflammation, and antioxidation effects.

Chinese medicine tongxinluo significantly lowers serum lipid levels and stabilizes vulnerable plaques in a rabbit model

UNLABELLED RELEVANCE TO ETHNOPHARMACOLOGY: Tongxinluo capsule is a compound preparation formulated on the basis of the meridian theory of traditional Chinese medicine and is officially approved for the treatment of angina pectoris and ischemic stroke in China. OBJECTIVES To test the hypothesis that the Chinese traditional medicine tongxinluo in capsule form has similar effects as simvastatin in lowering serum lipid levels and stabilizing vulnerable plaques. MATERIALS AND METHODS Thirty New Zealand white rabbits underwent balloon-induced abdominal aortic endothelial injury and were fed a diet of 1% cholesterol for 8 weeks. The rabbits were then randomly divided into three groups (n=10 each) for daily doses of tongxinluo capsule (1 g/kg), simvastatin (5 mg/kg) or no drugs for 12 weeks. At the end of week 20, plaque rupture was induced by pharmacological triggering. Serological, ultrasonographic, pathologic, immunohistochemical, and gene expression studies were performed. RESULTS The incidence of plaque rupture with tongxinluo and simvastatin treatment was significantly lower than that with control treatment (0% for both drug treatments vs. 56.0%; P<0.05). Values of serum lipid profile, inflammatory markers, and pathological and immunohistological assays were significantly improved in the tongxinluo- and simvastatin-treated groups than in the control group. The simvastatin-treated group showed lower serum lipid levels than the tongxinluo-treated group. CONCLUSIONS Treatment with the Chinese medicine tongxinluo was as effective as simvastatin in lowering serum lipid levels, inhibiting plaque inflammation and preventing vulnerable plaques from rupture and may provide an alternative therapy for atherosclerosis.

Dominant-negative mutation of monocyte chemoattractant protein-1 prevents vulnerable plaques from rupture in rabbits independent of serum lipid levels

Active inflammation is an important feature of vulnerable plaques, and monocyte chemoattractant protein‐1 (MCP‐1) is a key chemokine that promotes monocyte–endothelium binding and initiates inflammation. We aimed to determine whether dominant‐negative mutation of MCP‐1 could reverse atherosclerotic lesion progression and prevent vulnerable plaques from rupture regardless of serum lipid levels. The mutant MCP‐1 was produced by deletion of the N‐terminal amino acids 2 to 8 (7ND), and a eukaryotic expression vector plRES‐EGFP‐7ND was constructed. The transwell chamber was used to assay chemotaxis of monocytes in vitro. Thirty New Zealand white rabbits underwent balloon‐induced abdominal aortic endothelial injury and were randomly divided into control group without gene intervention (group A, n = 10), plRES‐EGFP‐7ND treatment group (group B, n = 10) and empty vector treatment group (group C, n = 10). All rabbits were fed a diet of 1% cholesterol for 8 weeks, and then group A rabbits were killed, whereas groups B and C rabbits received an intramuscular injection of plRES‐EGFP‐7ND and an empty lipofectamine, respectively, and remained on a high cholesterol diet for 4 weeks. At the end of week 12, groups B and C rabbits underwent pharmacological triggering by injection with Chinese Russellis viper venom and histamine. Serum lipids and inflammatory markers were measured, and high‐frequency ultra‐sonography and intravascular ultrasound imaging were performed. Immunohistochemistry and RT‐PCR were used to examine expression of inflammatory markers in the plaques. In vitro transfection of plRES‐EGFP‐7ND resulted in a significant inhibition of monocyte chemotaxis (P < 0.05) and in vivo transfection of plRES‐EGFP‐7ND significantly increased the thickness of the fibrous caps and decreased plaque vulnerability index. The incidence of plaque rupture in group B was 0% as compared with 56% in the empty vector treatment group (P< 0.05). The serum levels and expression of inflammatory markers were significantly reduced in group B. In conclusion, PIRES‐EGFP‐7ND transfection effectively inhibits plaque inflammation, reverses plaque progression and prevents vulnerable plaques from rupture. These therapeutic effects are independent of serum lipid levels and demonstrate that inhibition of plaque inflammation alone without lipid lowering can stabilize vulnerable plaques.

Peak radial and circumferential strain measured by velocity vector imaging is a novel index for detecting vulnerable plaques in a rabbit model of atherosclerosis

AIMS To evaluate the reliability of velocity vector imaging (VVI) for detecting vulnerable plaques. METHODS AND RESULTS After aortic balloon injury, 60 rabbits were fed a 1% cholesterol diet for 10 weeks and normal chow for another 6 weeks. Adenovirus containing p53 or lac Z was then injected into the aortic plaques and rabbits were divided into p53-treated group (n=20), lac Z-treated group (n=20) and blank control group (n=20). Peak longitudinal (LSp), radial (RSp) and circumferential (CSp) strain of plaques was measured using VVI at the end of week 18 before pharmacological triggering. Higher RSp and CSp and lower LSp were found in ruptured than those in non-ruptured plaques, and RSp, CSp and LSp correlated well with the fibrous cap thickness and plaque content of macrophages, smooth muscle cells and collagen (all p<0.01). A logistic regression model showed that both RSp (RR: 8.96, 95% CI: 5.3575-10.4857, p<0.001) and CSp (RR: 8.45, 95% CI: 5.9043-9.1043, p<0.001) were significant predictors of plaque rupture. RSp and CSp had a sensitivity of 88.0% and 88.6% and a specificity of 88.6% and 92.0% to predict plaque disruption, respectively. CONCLUSION VVI offers a new and noninvasive technique for measuring the peak strain of atherosclerotic plaques and RSp and CSp are a novel index with a high sensitivity and specificity for detecting plaques vulnerable to rupture.

Intraplaque injection of Ad5‐CMV.p53 aggravates local inflammation and leads to plaque instability in rabbits

This study aims to develop a new animal model of vulnerable plaques and investigate the potential mechanisms of exogenous p53‐induced plaque instability. Forty rabbits underwent aortic balloon injury, were fed a 1% cholesterol diet for 10 weeks and then normal chow for 6 weeks. Rabbits were divided into Ad5‐CMV.p53‐treated group (n= 16), Ad5‐CMV.lac Z‐treated group (n= 16) and blank control group (n= 8). Under the guidance of intravascular ultrasound, a 50‐μl suspension of adenovirus containing p53 or lac Z was injected into the largest plaque of the first two groups, respectively, and these rabbits received pharmacological triggering 2 weeks later. In 76.9% of rabbits with p53 transfection, plaque rupture was found, which was significantly (P < 0.05) higher than that in the Ad5‐CMV.lac Z‐treated plaques (23.1%), or blank controls plaques (0%). Increased apoptotic cells, and subsequently, decreased vascular smooth muscle cells and collagen content, enhanced intima macrophage accumulation, increased C‐reactive protein (CRP) and matrix metalloproteinases staining and high serum levels of high sensitive CRP (hs‐CRP) and monocyte chemoattractant protein‐1 (MCP‐1) were observed in Ad5‐CMV.p53‐treated rabbits. However, a binary logistic regression model revealed that hs‐CRP concentration rather than apoptosis rate played an independent role in plaque rupture with an odds ratio as 1.314 (95% CI: 1.041–1.657, P= 0.021), and there were high positive correlations between inflammatory biomarkers (hs‐CRP or MCP‐1) and apoptosis (R2= 0.761, and R2= 0.557, respectively, both P < 0.01). Intraplaque injection of p53 gene provides a safe and effective method for inducing plaque vulnerability in rabbits. The destabilizing effect of p53 overexpression is mediated mainly through apoptosis‐enhanced inflammation rather than cell apoptosis itself.

Effects of loading dose of atorvastatin before percutaneous coronary intervention on periprocedural myocardial injury.

ObjectivesTo investigate the effects of loading dose of atorvastatin on periprocedural myocardial injury and inflammatory reaction in patients with non-ST segment elevation (NSTE) acute coronary syndromes (unstable angina or NSTE acute myocardial infarction). MethodsA total of 81 patients with NSTE-acute coronary syndromes were randomly divided into the pretreatment with atorvastatin group [80 mg 12 h before percutaneous coronary intervention (PCI), with a further 40 mg preprocedure dose] (n=41) or the placebo group (n=40). The main end point was a 30-day incidence of major adverse cardiac events (cardiac death, nonfatal acute myocardial infarction, or revascularization with either PCI or coronary artery bypass grafting). Creatine kinase-MB, cardiac troponin I, and high-sensitivity C-reactive protein levels were measured at the baseline and at 8 and 24 h after the procedure. ResultsMajor adverse cardiac events occurred in 2.4% of patients in the atorvastatin group and 22.5% of those in the placebo group (P=0.0161). This difference was mostly because of reduction in the incidence of myocardial infarction (2.4 vs. 20.0%; P=0.0307). Markers of the two groups were elevated after PCI; however, the higher values of creatine kinase-MB, cardiac troponin I, and high-sensitivity C-reactive protein in the atorvastatin treatment group were significantly lower than those in the placebo group (P<0.01). ConclusionShort-term pretreatment with a high dose of atorvastatin significantly reduces procedural myocardial injury in early PCI.

Doxycycline stabilizes vulnerable plaque via inhibiting matrix metalloproteinases and attenuating inflammation in rabbits.

Enhanced matrix metalloproteinases (MMPs) activity is implicated in the process of atherosclerotic plaque instability. We hypothesized that doxycycline, a broad MMPs inhibitor, was as effective as simvastatin in reducing the incidence of plaque disruption. Thirty rabbits underwent aortic balloon injury and were fed a high-fat diet for 20 weeks. At the end of week 8, the rabbits were divided into three groups for 12-week treatment: a doxycycline-treated group that received oral doxycycline at a dose of 10 mg/kg/d, a simvastatin-treated group that received oral simvastatin at a dose of 5 mg/kg/d, and a control group that received no treatment. At the end of week 20, pharmacological triggering was performed to induce plaque rupture. Biochemical, ultrasonographic, pathologic, immunohistochemical and mRNA expression studies were performed. The results showed that oral administration of doxycycline resulted in a significant increase in the thickness of the fibrous cap of the aortic plaque whereas there was a substantial reduction of MMPs expression, local and systemic inflammation, and aortic plaque vulnerability. The incidence of plaque rupture with either treatment (0% for both) was significantly lower than that for controls (56.0%, P<0.05). There was no significant difference between doxycycline-treated group and simvastatin-treated group in any serological, ultrasonographic, pathologic, immunohistochemical and mRNA expression measurement except for the serum lipid levels that were higher with doxycycline than with simvastatin treatment. In conclusion, doxycycline at a common antimicrobial dose stabilizes atherosclerotic lesions via inhibiting matrix metalloproteinases and attenuating inflammation in a rabbit model of vulnerable plaque. These effects were similar to a large dose of simvastatin and independent of serum lipid levels.

Huang-lian-jie-du-tang Protects Rats from Cardiac Damages Induced by Metabolic Disorder by Improving Inflammation-mediated Insulin Resistance

Huang-lian-jie-du-tang (HLJDT), a traditional Chinese medicine, has been shown to improve insulin resistance (IR) induced by inflammation, a key event in the development of metabolic syndrome (MS). The present study aimed to investigate the protective effects of HLJDT on MS and explore the underlying mechanism. MS rats were established with obese-diets and treated with normal saline, aspirin or HLJDT. The myocardial lesions were identified by echocardiogram, transmission electron microscope, and Sirius-red staining. The inflammatory cytokines were measured by ELISA and real-time PCR. The activation of NF-κB, JNK, SOCS3, IRS1 and AKT in the heart was detected by immunohistochemistry and Western blot analysis. Compared with the controls, MS rats developed obvious obesity, hypertension, dyslipidemia, IR, inflammation, and cardiac damage. Moreover, phosphorylated IRS-1 at Ser307 was correlated with the activation of NF-κB, JNK and SOCS3 and the inhibition of AKT in the heart from MS rats. These data suggest that serine phosphorylation of IRS-1 in response to inflammation is mediated, in part, by NF-κB, JNK and SOCS3. Notably, HLJDT inhibited the activation of NF-κB and reduced serine phosphorylation of IRS-1. In summary, HLJDT protects myocardium from IR-mediated injury by inhibiting serine phosphorylation of IRS-1 in MS rats.

Is overall blockade superior to selective blockade of adrenergic receptor subtypes in suppressing left ventricular remodeling in spontaneously hypertensive rats

To test the hypothesis that nonselective blockade of adrenergic receptor (AR) subtypes is superior to selective blockade of AR subtypes in suppressing left ventricular (LV) remodeling induced by hypertension. Sixty-four spontaneously hypertensive rats (SHR) were randomly divided into four groups: bisoprolol-treated, propranolol-treated, carvedilol-treated and no treatment groups (n=16, each). Sixteen Wistar–Kyoto (WKY) rats served as a control group. Echocardiography and cardiac catheterization were carried out to record the mitral flow velocity ratio of E wave to A wave (E/A), LV mass index (LVMI), maximal rising (dp/dtmax) and falling (−dp/dtmax) rate of the LV pressure and LV relaxation time constant (τ). The mRNA and protein expression levels of AR, protein kinase(PK) and G-protein subtypes, intracellular free calcium (Ca2+) concentration and cardiocyte apoptoisis rate were determined. Three drug-treated groups showed higher velocity ratio of E wave to A wave (E/A) and −dp/dtmax and lower systolic blood pressure (SBP), LVMI, τ, apoptosis rate and intracellular free Ca2+ concentration than the no treatment group. The mRNA expression levels of AR-α1B in the carvedilol group were significantly lower than the other two drug-treated groups. The mRNA expression levels of AR-β1, AR-β2 and Gsα were significantly higher in the three drug-treated groups than in the no treatment group, with the expression levels of AR-β2 being the highest in the carvedilol-treated group. The protein expression levels of PKA and PKC subtype α and δ were lower in the three drug-treated groups than in the no treatment group. Overall blockade of AR subtypes is not superior to selective blockade of AR subtypes in suppressing LV remodeling in SHR. Although carvedilol is the most effective in attenuating cardiocyte apoptosis, normalizing AR-α1B and Gsα expression and increasing AR-β2 expression.