Transauricular balloon angioplasty in rabbit thoracic aorta: a novel model of experimental restenosis

Protein tyrosine nitration in atherosclerotic endothelial dysfunction

Accumulation of reactive oxygen species (ROS) can induce both protein tyrosine nitration and endothelial dysfunction in atherosclerosis. Endothelial dysfunction refers to impaired endothelium-dependent vasorelaxation that can be triggered by an imbalance in nitric oxide (NO) production and consumption. ROS reacts with NO to generate peroxynitrite, decreasing NO bioavailability. Peroxynitrite also promotes protein tyrosine nitration in vivo that can affect protein structure and function and further damage endothelial function. In this review, we discuss the process of protein tyrosine nitration, increased expression of nitrated proteins in cardiovascular disease and their association with endothelial dysfunction, and the interference of tyrosine nitration with antioxidants and the protective role in endothelial dysfunction. These may lead us to the conception that protein tyrosine nitration may be one of the causes of endothelial dysfunction, and help us gain information about the mechanism of endothelial dysfunction underlying atherosclerosis.

Overexpression of Salusin-α Inhibits Vascular Intimal Hyperplasia in an Atherosclerotic Rabbit Model

Inhibiting vascular endothelial foam is the focus of clinical attention. Using SonoVue (an ultrasound contrast agent), the salusin-α gene was transfected into the arterial intima of an atherosclerotic rabbit model induced by a high-fat diet in this study. Subsequently the model of blood lipid indexes, the pathological structure of the intima, and changes in molecules regulating atherosclerosis were investigated. The high-density lipoprotein C and apolipoprotein A values in the salusin-α gene overexpression (P) group were higher than those in the salusin-α gene interference (RP) group (P < 0.05), whereas the total cholesterol, low-density lipoprotein C, and apolipoprotein B values were reversed. Rabbits in the P group showed significantly thinner vascular intimal thickness than that of other experimental groups (P < 0.05). The expression of positive regulators of atherosclerosis (ABCA1, ABCG1) was higher in the P group than that in the RP group (P < 0.05), and the opposite effect was observed for negative regulators (ACAT1, CD36). Thus, our results showed that the overexpression of salusin-α gene inhibited the proliferation of the vascular intima, thereby throwing some light on understanding the mechanism how salusin-α gene expression interfered with the foaming of vascular intimal cells.

A cynomolgus monkey model of carotid atherosclerosis induced by puncturing and scratching of the carotid artery combined with a high-fat diet

Cardio-cerebrovascular disease is one of the three major causes of mortality in humans and constitutes a major socioeconomic burden. Carotid atherosclerosis (CAS) is a very common lesion of the arterial walls, which leads to narrowing of the arteries, in some cases occluding them entirely, increasing the risk of cardiovascular events. The aim of the present study was to evaluate a cynomolgus monkey model of carotid atherosclerosis (CAS) induced by puncturing and scratching combined with a high-fat diet. A total of 12 cynomolgus monkeys were randomly divided into four groups: A, puncturing and scratching carotid artery intimas + high-fat diet (n=3); B, puncturing and scratching carotid artery intimas + regular diet (n=3); C, high-fat diet only (n=3); and D, regular diet only (n=3). Blood was harvested at weeks 4, 6 and 8 and plasma lipid levels were assessed. At week 8, monkeys were sacrificed and carotid arteries were harvested for hematoxylin and eosin (H&E) staining to observe pathological changes. The results revealed that a high-fat diet led to increased plasma lipid levels and accelerated plaque formation. Carotid color Doppler ultrasonography was performed and, along with H&E staining, revealed plaque formation in group A. In summary, the results of the present study suggest that a cynomolgus monkey model of CAS model may be successfully constructed by puncturing and scratching of the carotid artery intimas in combination with a high-fat diet.

Inhibition of Atherosclerosis Progression, Intimal Hyperplasia, and Oxidative Stress by Simvastatin and Ivabradine May Reduce Thoracic Aorta's Stiffness in Hypercholesterolemic Rabbits

AIMS

This study aims to evaluate atherosclerosis, oxidative stress, and arterial stiffness attenuation by simvastatin and ivabradine in hyperlipidemic rabbits.

METHODS AND RESULTS

Forty rabbits were randomly divided into 4 groups: atherogenic diet (group C), atherogenic diet plus simvastatin (group S), atherogenic diet plus ivabradine (group I), and atherogenic diet plus simvastatin and ivabradine (group S + I). After 9 weeks, rabbits were euthanized and descending aortas excised for mechanical testing. Atherogenic diet induced the development of significant atherosclerotic lesions in group C animals but in none of groups S, I, and S + I. RAM-11 and HHF-35-positive cells were significantly reduced in groups S, I, and S + I compared with group C (P < .001). A significant neointimal hyperplasia and intima-media ratio reduction was demonstrated in groups S (P = .015 and P < .001), I (P = .021 and P < .001), and S + I (P = .019 and P < .001) compared with group C. Protein nitrotyrosine levels were significantly decreased in group S compared with group C (P = .009), and reactive oxygen species levels were decreased in group I compared with group C (P = .011). Aortic stiffness was significantly reduced in groups S, I, and S + I compared with group C (P = .003, P = .011, and P = .029).

CONCLUSION

Simvastatin and ivabradine significantly inhibited intimal hyperplasia and oxidative stress contributing to aortic stiffness reduction in hyperlipidemic rabbits.