Animals ; Atherosclerosis ; diet therapy ; physiopathology ; Humans ; Plaque, Atherosclerotic ; drug therapy

To test the hypothesis that concentration polarization of atherogenic lipids may occur in the arterial system and play an important role in localization of atherosclerosis, we simulated and measured in vitro the luminal surface concentration of low density lipoprotein (LDL) in local stenosis at the distal end of carotid artery by number simulation and laser scanning confocal microscopy, then we designed carotid stenosis model to test the role of LDL concentration polarization in atherogenesis. The in vitro experiment showed that the luminal surface LDL concentration was higher than the bulk concentration as predicted by the concentration polarization theory. The relative luminal surface LDL concentration changed with the flow velocity and ratio of stenosis. The wall concentration of LDL was highest in the round tube with 40% stenosis at the same velocity, while the wall concentration of LDL was higher when Re was 250 than Re was 500 at the same extent of narrowness. The animal experiment also revealed that general atherogenic plaques obviously occurred at the distal end of local stenosis where concentration polarized. The results strongly support our hypothesis that concentration polarization of lipoproteins occurs in local stenosis at the distal end of carotid artery, and this in turn promotes the localization of atherosclerosis which develops in the arterial system.
Animals ; Atherosclerosis ; physiopathology ; Carotid Stenosis ; physiopathology ; Disease Models, Animal ; Lipoproteins, LDL ; metabolism

Arteries ; physiopathology ; surgery ; Atherosclerosis ; diagnostic imaging ; physiopathology ; surgery ; Hemodynamics ; Humans ; Radiography

This study examined the protective effect of ischemic postconditioning (IPoC) and minocycline postconditioning (MT) on myocardial ischemia-reperfusion (I/R) injury in atherosclerosis (AS) animals and the possible mechanism. Forty male healthy rabbits were injected with bovine serum albumin following feeding on a high fat diet for 6 weeks to establish AS model. AS rabbits were randomly divided into 3 groups: (1) I/R group, the rabbits were subjected to myocardial ischemia for 35 min and then reperfusion for 12 h; (2) IPoC group, the myocardial ischemia lasted for 35 min, and then reperfusion for 20 s and ischemia for 20 s [a total of 3 cycles (R20s/I20s×3)], and then reperfusion was sustained for 12 h; (3) MT group, minocycline was intravenously injected 10 min before reperfusion. The blood lipids, malondialdehyde (MDA), superoxide dismutase (SOD), soluble cell adhesion molecule (sICAM), myeloperoxidase (MPO), and cardiac troponin T (cTnT) were biochemically determined. The myocardial infarction size (IS) and apoptosis index (AI) were measured by pathological examination. The expression of bcl-2 and caspase-3 was detected in the myocardial tissue by using reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the AS models were successfully established. The myocardial IS, the plasma levels of MDA, sICAM, MPO and cTnT, and the enzymatic activity of MPO were significantly decreased, and the plasma SOD activity was significantly increased in IPoC group and MT group as compared with I/R group (P<0.05 for all). The myocardial AI and the caspase-3 mRNA expression were lower and the bcl-2 mRNA expression was higher in IPoC and MT groups than those in I/R group (all P<0.05). It is concluded that the IPoC and MT can effectively reduce the I/R injury in the AS rabbits, and the mechanisms involved anti-oxidation, anti-inflammation, up-regulation of bcl-2 expression and down-regulation of caspase-3 expression. Minocycline can be used as an effective pharmacologic postconditioning drug to protect myocardia from I/R injury.
Animals ; Atherosclerosis ; physiopathology ; Ischemic Preconditioning, Myocardial ; methods ; Male ; Minocycline ; pharmacology ; Myocardial Reperfusion Injury ; physiopathology ; Rabbits ; Reperfusion Injury ; physiopathology

INTRODUCTIONAdults with obstructive sleep apnoea (OSA) are well documented to be at high risk for cardiovascular abnormalities. Growing evidence suggests that OSA is also associated with cardiovascular consequences in children. The purpose of this review is to examine the available data on this association in children.

METHODSPrimary studies were extracted from a MEDLINE search limited to those published between 1970 and 2008. The keywords used included child, sleep disordered breathing, sleep apnoea, snoring, blood pressure and hearts. The relevant articles were selected by consensus between 2 authors.

RESULTSThe results suggested that OSA was consistently associated with hypertension. Meta-analysis of risk of hypertension in those with high apnoea-hypopnoea index was undertaken. A combined odds ratio equal to 3.15 was found (95% confidence interval, 2.01 to 4.93). There was evidence for increased sympathetic activation, decreased arterial distensibility and ventricular hypertrophy in children with OSA.

CONCLUSIONChildhood OSA is associated with blood pressure dysregulation. The association of OSA with other cardiovascular morbidities requires further study in view of the limited data available currently.

Atherosclerosis ; physiopathology ; Blood Pressure ; physiology ; Cardiovascular System ; physiopathology ; Cerebral Arteries ; physiopathology ; Child ; Endothelium, Vascular ; physiopathology ; Heart Rate ; physiology ; Humans ; Hypertension ; physiopathology ; Hypertrophy, Left Ventricular ; physiopathology ; Pulmonary Heart Disease ; physiopathology ; Regional Blood Flow ; Sleep Apnea, Obstructive ; complications ; physiopathology ; Ventricular Function

To establish and observe rabbit hyperlipemia and atherosclerosis model, we combined the method of high-lipid diet and immuoreactive injure. We divided 45 New Zealand rabbit into control group and high-lipid group. According to the time (4, 8, 12 weeks) of established model, the control group and high-lipid group were divided into 3 groups respectively. The blood-lipid, the hemodynamics parameter and vascular intima were determined and observed. The results showed: (1) After feeding 4, 8, 12 weeks, TC and LDL-C of the high-lipid group in the serum increased obviously. After feeding 8 week, TG of the high-lipid group began to increase obviously. HDL-C of the high-lipid group was higher than control group, but with a descendent trend. (2) Blood viscosity of the high-lipid group increased obviously under the 0.512 S(-1) and 5.96 S(-1) at 12 week. Blood flow increased obviously at 8 and 12 week. SBP increased evidently at 8 and 12 week. Alteration of the plasma viscosity and vascular diameter were not obvious. (3) By observing with optical microscope the intima of the control group is smooth. The intima of the high-lipid group has a light incrassation at 4 week. The intima of the high-lipid group has a obvious incrassation at 8 and 12 week. By observing with through transmission electron microscopy (TEM), the lipid vacuole is under the endothelium cell. (4) By adopting the immunohistochemistry, the foam cell that derived from smooth muscle cell were determined. We concluded that the blood lipid can have a prefigurative role in atherosclerosis; blood flow and blood pressure and blood viscosity increase at low shear rate in the course of the atherosclerosis; vascular intima is incrassate and the composition of the AS plaque is variational continually.
Animals ; Atherosclerosis ; blood ; pathology ; physiopathology ; Endothelium, Vascular ; pathology ; Hemodynamics ; Hyperlipidemias ; blood ; pathology ; physiopathology ; Lipids ; blood ; Male ; Rabbits

Arteriosclerosis and its complications, such as heart attack and stroke, are the major causes of death in developed countries. It was believed that age, hyperlipidemia, hypertension, diabetes and smoking are common risk factors for cardiovascular disease. In addition, overwhelming clinical and epidemiological studies have identified homocysteine (Hcy) as a significant and independent risk factor for cardiovascular disease. In healthy individuals, plasma Hcy is between 5 and 10 micromol/L. One cause of severe hypehomocys- teinemia (HHcy) is the deficiency of cystathionine beta-synthase (CBS), which converts Hcy to cystathionine. CBS homozygous deficiency results in severe HHcy with Hcy levels up to 100 to 500 micromol/L. Patients with severe HHcy usually present with neurological abnormalities, premature arteriosclerosis. It has been reported that lowering plasma Hcy improved endothelial dysfunction and reduced incidence of major adverse events after percutaneous coronary intervention. The mechanisms by which Hcy induces atherosclerosis are largely unknown. Several biological mechanisms have been proposed to explain cardiovascular pathological changes associated with HHcy. These include: (1) endothelial cell damage and impaired endothelial function; (2) dysregulation of cholesterol and triglyceride biosynthesis; (3) stimulation of vascular smooth muscle cell proliferation; (4) thrombosis activation and (5) activation of monocytes. Four major biochemical mechanisms have been proposed to explain the vascular pathology of Hcy. These include: (1) autooxidation through the production of reactive oxygen species; (2) hypomethylation by forming SAH, a potent inhibitor of biological transmethylations; (3) nitrosylation by binding to nitric oxide or (4) protein homocysteinylation by incorporating into protein. In summary, our studies, as well as data from other laboratories support the concept that Hcy is causally linked to atherosclerosis, and is not merely associated with the disease. Although folic acid, vitamin B12 and B6 can lower plasma Hcy levels, the long-term effects on cardiovascular disease risk are still unknown and judgments about therapeutic benefits await the findings of ongoing clinical trials.
Animals ; Atherosclerosis ; etiology ; physiopathology ; Cystathionine beta-Synthase ; deficiency ; genetics ; Homocysteine ; metabolism ; Humans ; Hyperhomocysteinemia ; complications ; physiopathology ; Reactive Oxygen Species ; metabolism

In this paper a kind of arterial bifurcation vessel's hemodynamic characteristics are studied with the boundary element method, and the blood flowing velocity vector distributions are calculated when there is pathologic change in the branch vessel wall and when there is no pathologic change. The shear stress value at the lateral wall and that at the medial wall are compared when there is pathologic change in the main branch vessel wall and when there is no pathologic change. Moreover, the flow field distribution and the pressure on the particle surface are calculated, when there is flow-round particle at the place of bifurcation. The move tendency of the particle is judged, and the possible factors in causing atherosclerosis are analyzed.
Arteries ; physiology ; physiopathology ; Atherosclerosis ; physiopathology ; Blood Flow Velocity ; Computer Simulation ; Hemodynamics ; physiology ; Humans ; Models, Cardiovascular ; Stress, Mechanical

Gap junctions play a critical role in electrical synchronization and exchange of small molecules between neighboring cells; connexins are a family of structurally related transmembrane proteins that assemble to form vertebrate gap junctions. Hyperglycemia changes the structure gap junction proteins and their expression, resulting in obstruction of neural regeneration, vascular function and wound healing, and also promoting vascular atherosclerosis. These pathogenic factors would cause diabetic foot ulcers. This article reviews the involvement of connexins in pathogenesis of diabetic foot.
Atherosclerosis ; Connexins ; metabolism ; Diabetic Foot ; pathology ; Gap Junctions ; metabolism ; Humans ; Hyperglycemia ; physiopathology ; Regeneration ; Wound Healing

Hyperhomocysteinemia (HHcy) has been recognized as an independent risk factor for atherosclerosis for more than 30 years, but the mechanisms by which HHcy leads to atherosclerosis are not well fully understood. In this review, we will summarize the immunoregulatory effects of homocysteine on cardiovascular diseases from humoral immunity, monocyte/macrophage and T lymphocyte activity. Homocysteine can induce chemokine and cytokine secretion in monocytes and T lymphocytes and also directly stimulate B lymphocyte proliferation and IgG secretion. In addition, the cellular mechanisms that may explain the pro-inflammatory effect of HHcy are included. Homocysteine may directly or indirectly lead to oxidative stress or endoplasmic reticulum (ER) stress. Elevated levels of homocysteine also decrease the bioavailability of nitric oxide and modulate the levels of other metabolites including S-adenosyl methionine and S-adenosyl homocysteine which may result in cardiovascular diseases.
Animals ; Atherosclerosis ; Cardiovascular Diseases ; immunology ; physiopathology ; Homocysteine ; physiology ; Humans ; Hyperhomocysteinemia ; complications ; Macrophages ; Nitric Oxide ; Oxidative Stress