Pathophysiology of atherosclerosis

Autologous adipose mesenchymal stem cell administration in arteriosclerosis and potential for anti-aging application: a retrospective cohort study

Objective

Arteriosclerosis is an age-related disease and a leading cause of cardiovascular disease. In animal experiments, mesenchymal stem cells and its culture-conditioned medium have been shown to be promising tools for prevention or treatment of arteriosclerosis. On the basis of these evidences, we aimed to assess whether administration of autologous adipose-derived mesenchymal stem cells (Ad-MSC) is safe and effective for treatment of arteriosclerosis.

Methods

We retrospectively reviewed clinical records of patients with arteriosclerosis who had received autologous Ad-MSC administration at our clinic. Patients’ characteristics were recorded and data on lipid profile, intimal-media thickness (IMT), cardio-ankle vascular index (CAVI), and ankle-brachial index (ABI) before and after Ad-MSC administration were collected and compared.

Results

Treatment with Ad-MSC significantly improved HDL, LDL, and remnant-like particle (RLP) cholesterol levels. No adverse effect or toxicity was observed in relation to the treatment. Of the patients with abnormal HDL values before treatment, the vast majority showed improvement in the values. Overall, the measurements after treatment were significantly increased compared with those before treatment (p < 0.01). In addition, decreases in LDL cholesterol and RLP levels were observed after treatment in patients who had abnormal LDL cholesterol or RLP levels before treatment. The majority of patients with pre-treatment abnormal CAVI values had improved values after treatment. In patients with available IMT values, a significant decrease in the IMT values was found after therapy (p < 0.01). All patients with borderline arteriosclerosis disease had improved laboratory findings after treatment. In general, post-treatment values were significantly decreased as compared with pre-treatment values. Of the patients with normal ABI values before treatment at the same time as CAVI, the vast majority remained normal after treatment.

Conclusions

These findings suggest that Ad-MSC administration is safe and effective in patients developing arteriosclerosis, thereby providing an attractive tool for anti-aging application.

The Relationship of Various Factors in the Pathogenesis of Atherosclerosis

In this study we investigated the levels of lipid parameters, fibronectin, tissue-type plasminogen activator and plasminogen activator inhibitor (t-PA-PAI-1) complex and si alidase in patients with coronary heart disease and a control group. Total cholesterol, triglyceride, low-density lipoprotein (LDL), and very-low-density lipoprotein (VLDL) cholesterol and lipoprotein Lp(a), levels in patients with coronary heart disease were found to be significantly higher than in the control group (p < .001). High-density lipoprotein (HDL) cholesterol levels in patient group were significantly lower than control group (p < .001). Plasma fibronectin and t-PA-PAI-1 complex levels in patients with coronary heart disease were found to be significantly higher than control group (p < .05 and p < .001, respectively). In addition, we found that serum sialidase levels in patients with coronary heart disease were significantly higher than in the control group (p < .001). The electrophoretic mobility of lipoproteins from patients with coronary heart dis ease was found to be greater than those from the control group. As a result Lp(a) may play an important role in the pathogen esis of atherosclerosis by causing foam cell formation because of interacting with LDL or fibronectin and by interfering with the fibrinolytic system because of binding to plasminogen re ceptors. In addition, modifications of Lp(a) (including desi alylation) may effect these events. Key words: Coronary heart disease—tPA-PAI-1 complex-Fibronectin-sialidase-Lipid parameters.

Plaque microstructures in patients with coronary artery disease who achieved very low low-density lipoprotein cholesterol levels

OBJECTIVE

Lowering low-density lipoprotein cholesterol (LDL-C) with statins reduces cardiovascular events and slows plaque progression. While this therapeutic approach has been reported to favorably modify plaque composition, this is not well characterized in humans. Also, the benefit of achieving LDL-C levels below current recommended targets remains unknown. Frequency-domain optical coherence tomography (FD-OCT) enables visualization of plaque microstructures associated with plaque instability. We investigated plaque morphologies in patients with low LDL-C levels by using FD-OCT.

METHODS

293 and 122 non-obstructive lipid and fibrous plaques in 280 stable statin-treated CAD patients were evaluated by FD-OCT imaging in vessels requiring percutaneous coronary intervention. Study subjects were stratified according to achieved LDL-C levels (<50, 50-70, 70-100, <100 mg/dL). FD-OCT derived plaque microstructures were compared.

RESULTS

LDL-C levels <50 mg/dL and <70 mg/dL were observed in 13.9% (39/280) and 29.2% (82/280) of patients, respectively. Patients with LDL-C <50 mg/dL were more likely to be older (p < 0.001) and receive a high-dose statin (p = 0.01). On FD-OCT imaging, patients with LDL-C <50 mg/dL were more likely to have fibrous plaque (51.7, 43.2, 22.2 and 12.3%, p = 0.01) and less likely to have lipid plaques (48.2, 56.7, 77.7 and 87.6%, p = 0.01). In addition, LDL-C level was significantly associated with lipid arc (173 ± 76, 175 ± 88, 196 ± 102 and 234 ± 85°, p = 0.01) and fibrous cap thickness (139.9 ± 93.9, 103.1 ± 66.4, 92.5 ± 48.5 and 92.1 ± 47.8 um, p = 0.001). In particular, the smallest lipid arc and thickest fibrous cap were observed in patients who achieved LDL-C <50 mg/dL. Multivariable analysis revealed LDL-C levels (beta coefficient -0.254, p = 0.009) and high-dose statin use (beta coefficient 1.814, p = 0.003) to independently associate with fibrous cap thickness.

CONCLUSIONS

More stable plaque features were observed within non-obstructive atheromas in patients with very low LDL-C levels. These findings underscore LDL-C level to stabilize plaques in patients with CAD and high residual atherosclerotic risk.

Validated context-dependent associations of coronary heart disease risk with genotype variation in the chromosome 9p21 region: the Atherosclerosis Risk in Communities study

Markers of the chromosome 9p21 region are regarded as the strongest and most reliably significant genome-wide association study (GWAS) signals for Coronary heart disease (CHD) risk; this was recently confirmed by the CARDIoGRAMplusC4D Consortium meta-analysis. However, while these associations are significant at the population level, they may not be clinically relevant predictors of risk for all individuals. We describe here the results of a study designed to address the question: What is the contribution of context defined by traditional risk factors in determining the utility of DNA sequence variations marking the 9p21 region for explaining variation in CHD risk? We analyzed a sample of 7,589 (3,869 females and 3,720 males) European American participants of the Atherosclerosis Risk in Communities study. We confirmed CHD-SNP genotype associations for two 9p21 region marker SNPs previously identified by the CARDIoGRAMplusC4D Consortium study, of which ARIC was a part. We then tested each marker SNP genotype effect on prediction of CHD within sub-groups of the ARIC sample defined by traditional CHD risk factors by applying a novel multi-model strategy, PRIM. We observed that the effects of SNP genotypes in the 9p21 region were strongest in a sub-group of hypertensives. We subsequently validated the effect of the region in an independent sample from the Copenhagen City Heart Study. Our study suggests that marker SNPs identified as predictors of CHD risk in large population based GWAS may have their greatest utility in explaining risk of disease in particular sub-groups characterized by biological and environmental effects measured by the traditional CHD risk factors.

Angiotensin II induces the expression of tissue factor and its mechanism in human monocytes

The renin-angiotensin system (RAS) is linked with the vascular motion and the secretion of aldosterone. The purpose of the present study was to elucidate whether angiotensin II (Ang II) induces monocytes (Mo) to express tissue factor (TF) and if Ang II subtype 1 receptor (AT1R) antagonists inhibit the effect of Ang II. The roles of different intracellular signal transduction pathways and IkappaB/NF-kappaB in Ang II-induced TF expression of Mo were also studied to explore the mechanisms involved. Mo were isolated from heparinized human blood by a two-step gradient centrifugation, cultured in RPMI-1640 and exposed to Ang II and other test reagents. Mo TF activity and TF antigen were determined with a one-stage clotting method and ELISA, respectively, after the culture. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the TF mRNA levels in Mo. The level of IkappaBalpha in Mo was detected by Western blot analysis. Electrophoresis mobility shift assay (EMSA) was performed to evaluate the binding activity of NF-kappaB in Mo. The experiment results are as follows: (1) Ang II (10(-10)-10(-7) M) induced Mo to express TF activity but had no marked effect on other mononuclear cells. Ang II 10(-10)-10(-7) M) also caused increased TF mRNA expression and TF antigen from Mo in a dose-dependent manner. The TF antigen of Mo was elevated at 4 h after Mo was exposed to Ang II (10(-7) M) in culture, reached the peak at 6 h, and then declined from 12 h. The changes of TF activity were positively correlated with those of TF antigen. TF mRNA expression was elevated at 1 h, peaked at 3 h, and declined after 8 h. (2) Losartan (10(-6)-10(-5) M) significantly inhibited the stimulative effects of Ang II on TF activity, TF antigen and TF mRNA in Mo in a dose-dependent manner. (3) The protein kinase C (PKC) inhibitor, staurosporine, and the protein tyrosine kinase (PTK) inhibitor, genistein, both lowered TF levels in Mo, but the inhibitory effect of staurosporine was stronger than that of genistein. The effect of mitogen-activated protein kinase (MAPK) inhibitor, U0126, on monocytic TF expression was not significant. (4) Western blot analysis revealed that after Ang II (10(-7) M)exposure, levels of IkappaBalpha began to decrease at 15 min, reached a nadir at 60 min (P<.01), and recovered at 180 min. (5) EMSA showed that NF-kappaB binding activity started to increase at 15 min, reached a peak at 60 min, and returned to baseline at 180 min. The present data suggest that Ang II can directly induce TF expression in human Mo and this effect is mediated by AT1R. PKC may play the most important role in Ang II-induced TF expression among the three signal pathways detected. In addition, activation of NF-kappaB is also involved in the TF expression of Mo induced by Ang II.

Beneficial effects of statins in coronary artery disease--beyond lowering cholesterol

OBJECTIVE

To review the benefits of statins in coronary artery disease management beyond their cholesterol-lowering effects.

DATA SOURCES

A MEDLINE search (1966-May 2000) was conducted using the following terms: lovastatin, pravastatin, simvastatin, atorvastatin, fluvastatin, cerivastatin, endothelium, plaque stabilization, antithrombotic effects.

STUDY SELECTION

English-language human studies and case reports.

DATA EXTRACTION

Studies published demonstrating other mechanisms of statins' clinical beneficial effects were evaluated and reviewed.

DATA SYNTHESIS

The understanding of the pharmacologic effects of statins has led to the realization that the benefits of these agents extend beyond simply lowering cholesterol. These properties include beneficial effects on vessel endothelial tissue; decreased low-density lipoprotein oxidation and inflammation; ability to stabilize atherosclerotic plaques and perhaps promote regression; proliferative effects on smooth-muscle growths, possibly strengthening atherosclerotic plaques; antithrombotic effects by inhibiting platelet aggregation and stimulation of fibrinolytic factors; and improvement of blood viscosity and flow. With these actions, statins may benefit the situation of long-term atherosclerotic plaque formation and the setting of acute coronary syndrome.

CONCLUSIONS

Further large-scale studies are needed to determine the clinical importance and validity of these postulated beneficial effects of statins.

Water-soluble Hexasulfobutyl[60]fullerene inhibit low-density lipoprotein oxidation in aqueous and lipophilic phases

Oxidative modification of low-density lipoprotein (LDL) plays a pivotal role in the pathogenesis of atherosclerosis. Increasing the resistance of LDL to oxidation may therefore mitigate, or even prevent, atherosclerosis. A new water-soluble C60 derivative, hexasulfobutyl[60]fullerene [C60 - (CH2CH2CH2CH2-SO3Na)6; FC4S], consisting of 6 sulfobutyl moieties covalently bound onto the C60 cage is a potent free radical scavenger. This study explored the antioxidative effect of sulfobutylated fullerene derivatives (FC4S) on LDL oxidation. FC4S was found to be effective in protecting LDL against oxidation induced by either Cu2+ or azo peroxyl radicals generated initially in the aqueous or lipophilic phase, respectively. Levels of the oxidative products, conjugated diene and thiobarbituric acid-reactive substances, and the relative electrophoresis mobility of the LDL were decreased. The addition of 20 microM FC4S at the early stage of oxidation increased the kinetic lag time from 69 +/- 11 to 14 +/- 10 min (P < 0.05) and decreased the propagation rate from 17.1 +/- 2.6 to 6.3 +/- 1.0 mOD/min (P < 0. 005). Persistent suppression of peroxidation reaction was observed upon further addition of FC4S after full consumption of all endogenous antioxidants during the propagation period. Intravenous injection of hypercholesterolemic rabbits with FC4S (1 mg/kg/day) efficiently decreased atheroma formation. Data substantiate the use of FC4S as an excellent hydrophilic antioxidant in protecting atheroma formation, via removing free radicals, in either aqueous or lipophilic phase.

Infection and atherosclerosis--focus on cytomegalovirus and Chlamydia pneumoniae

BACKGROUND AND OBJECTIVE

Numerous studies have reported an association of coronary atherosclerosis and restenosis with certain bacterial and viral infections. This article reviews the pathophysiology of atherosclerosis, the role of infectious agents (i.e, cytomegalovirus and Chlamydia pneumoniae) in atherogenesis, and studies supporting the potential beneficial effects of antibiotics or antiviral agents in the management of atherosclerotic disease.

DATA SOURCES

English-language clinical studies, abstracts, and review articles pertaining to infectious agents and coronary atherosclerosis.

STUDY SELECTION AND DATA EXTRACTION

Relevant seroepidemiologic and pathologic studies and animal models evaluating the role of cytomegalovirus or C. pneumoniae in coronary atherosclerosis.

DATA SYNTHESIS

Studies evaluating the possible role of cytomegalovirus and C. pneumoniae in the pathogenesis of atherosclerosis, as well as studies examining the use of antimicrobial and antiviral agents for reduction of cardiovascular events, are reviewed and critiqued.

CONCLUSIONS

Current data do not allow us to determine whether infection is a cause or a cofactor of atherosclerosis. These uncertainties can be resolved by larger scale seroepidemiologic, pathologic, and interventional studies. Such efforts will contribute to identifying populations that are appropriate for particular surveillance or specific interventions, such as antibiotics or antiviral therapy.

The molecular markers of hemostatic activation on coronary artery disease

Endothelial cells, circulating platelets, and proteins of the coagulation and fibrinolytic systems are known to contribute to the hemostatic processes. Various molecular markers of hemostatic alteration are found in increased amounts in the circulation during the activation of this process. In this study, we investigated serum lipoprotein (a) and plasma platelet factor 4, beta-thromboglobulin, thrombin-anthithrombin complex, fibrinopeptid A, D-dimer, tissue plasminogen activator, tissue plasminogen activator inhibitor, and fibronectin levels in patients with coronary artery disease. The levels of all these markers were found to be significantly higher as compared to the control group. Our findings suggest that patients with coronary artery disease have greater blood coagulability than controls, and the use of molecular markers has become greatly important in clinical practice.

Heart failure: lessons learned over the past 25 years

Over the past 25 years, a great deal has been learned about the pathophysiology and management of heart failure--a major health problem whose prevalence and incidence have not declined, unlike other cardiovascular disorders. Several of these lessons are reviewed herein. However, despite these advances, important issues remain to challenge both the practicing physician and the research scientist.