Risk factors in coronary atherosclerosis athero-inflammation: the meeting point

Online application for the diagnosis of atherosclerosis by six genes

BACKGROUND

Atherosclerosis (AS) is a primary contributor to cardiovascular disease, leading to significant global mortality rates. Developing effective diagnostic indicators and models for AS holds the potential to substantially reduce the fatalities and disabilities associated with cardiovascular disease. Blood sample analysis has emerged as a promising avenue for facilitating diagnosis and assessing disease prognosis. Nonetheless, it lacks an accurate model or tool for AS diagnosis. Hence, the principal objective of this study is to develop a convenient, simple, and accurate model for the early detection of AS.

METHODS

We downloaded the expression data of blood samples from GEO databases. By dividing the mean values of housekeeping genes (meanHGs) and applying the comBat function, we aimed to reduce the batch effect. After separating the datasets into training, evaluation, and testing sets, we applied differential expression analyses (DEA) between AS and control samples from the training dataset. Then, a gradient-boosting model was used to evaluate the importance of genes and identify the hub genes. Using different machine learning algorithms, we constructed a prediction model with the highest accuracy in the testing dataset. Finally, we make the machine learning models publicly accessible by shiny app construction.

RESULTS

Seven datasets (GSE9874, GSE12288, GSE20129, GSE23746, GSE27034, GSE90074, and GSE202625), including 403 samples with AS and 325 healthy subjects, were obtained by comprehensive searching and filtering by specific requirements. The batch effect was successfully removed by dividing the meanHGs and applying the comBat function. 331 genes were found to be related to atherosclerosis by the DEA analysis between AS and health samples. The top 6 genes with the highest importance values from the gradient boosting model were identified. Out of the seven machine learning algorithms tested, the random forest model exhibited the most impressive performance in the testing datasets, achieving an accuracy exceeding 0.8. While the batch effect reduction analysis in our study could have contributed to the increased accuracy values, our comparison results further highlight the superiority of our model over the genes provided in published studies. This underscores the effectiveness of our approach in delivering superior predictive performance. The machine-learning models were then uploaded to the Shiny app's server, making it easy for users to distinguish AS samples from normal samples.

CONCLUSIONS

A prognostic Shiny application, built upon six potential atherosclerosis-associated genes, has been developed, offering an accurate diagnosis of atherosclerosis.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

Endothelial ACKR3 drives atherosclerosis by promoting immune cell adhesion to vascular endothelium

Atherosclerosis is the foundation of potentially fatal cardiovascular diseases and it is characterized by plaque formation in large arteries. Current treatments aimed at reducing atherosclerotic risk factors still allow room for a large residual risk; therefore, novel therapeutic candidates targeting inflammation are needed. The endothelium is the starting point of vascular inflammation underlying atherosclerosis and we could previously demonstrate that the chemokine axis CXCL12-CXCR4 plays an important role in disease development. However, the role of ACKR3, the alternative and higher affinity receptor for CXCL12 remained to be elucidated. We studied the role of arterial ACKR3 in atherosclerosis using western diet-fed Apoe^-/- mice lacking Ackr3 in arterial endothelial as well as smooth muscle cells. We show for the first time that arterial endothelial deficiency of ACKR3 attenuates atherosclerosis as a result of diminished arterial adhesion as well as invasion of immune cells. ACKR3 silencing in inflamed human coronary artery endothelial cells decreased adhesion molecule expression, establishing an initial human validation of ACKR3's role in endothelial adhesion. Concomitantly, ACKR3 silencing downregulated key mediators in the MAPK pathway, such as ERK1/2, as well as the phosphorylation of the NF-kB p65 subunit. Endothelial cells in atherosclerotic lesions also revealed decreased phospho-NF-kB p65 expression in ACKR3-deficient mice. Lack of smooth muscle cell-specific as well as hematopoietic ACKR3 did not impact atherosclerosis in mice. Collectively, our findings indicate that arterial endothelial ACKR3 fuels atherosclerosis by mediating endothelium-immune cell adhesion, most likely through inflammatory MAPK and NF-kB pathways.

Research methods for animal models of atherosclerosis (Review)

Atherosclerosis is a chronic inflammatory disease that threatens human health and lives by causing vascular stenosis and plaque rupture. Various animal models have been employed for elucidating the pathogenesis, drug development and treatment validation studies for atherosclerosis. To the best of our knowledge, the species used for atherosclerosis research include mice, rats, hamsters, rabbits, pigs, dogs, non-human primates and birds, among which the most commonly used ones are mice and rabbits. Notably, apolipoprotein E knockout (KO) or low-density lipoprotein receptor KO mice have been the most widely used animal models for atherosclerosis research since the late 20th century. Although the aforementioned animal models can form atherosclerotic lesions, they cannot completely simulate those in humans with respect to lesion location, lesion composition, lipoprotein composition and physiological structure. Hence, an appropriate animal model needs to be selected according to the research purpose. Additionally, it is necessary for atherosclerosis research to include quantitative analysis results of atherosclerotic lesion size and plaque composition. Laboratory animals can provide not only experimental tissues for in vivo studies but also cells needed for in vitro experiments. The present review first summarizes the common animal models and their practical applications, followed by focus on mouse and rabbit models and elucidating the methods to quantify atherosclerotic lesions. Finally, the methods of culturing endothelial cells, macrophages and smooth muscle cells were elucidated in detail and the experiments involved in atherosclerosis research were discussed.

Effects of the oxidative stress and genetic changes in varicose vein patients

Background

Etiology of the varicose veins is still partly known. It has been proposed that varicose veins formation might be a cause of the oxidative stress and/or cause from genetical reasons.

Method

The levels of antioxidant defense system enzymes, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, and an oxidative stress indicator, malondialdehyde, were measured in saphenous vein samples of varicose veins patients. Additionally, genetical polymorphism of glutathione S-transferase theta-1 has been studied.

Result

In this study, measurements revealed significant increase in catalase and malondialdehyde levels in the patient group, whereas superoxide dismutase and glutathione peroxidase and glutathione S-transferase enzyme activity and comparison of the null mutation frequency in the glutathione S-transferase theta-1 gene did not show a statistically significant difference.

Conclusion

We propose that the increase in catalase and malondialdehyde activities in our patient group may be related to each other. Increase in catalase levels, an antioxidant enzyme might be a compensatory response to the increase in malondialdehyde levels, an oxidative molecule.

Molecular targets of antihypertensive peptides: understanding the mechanisms of action based on the pathophysiology of hypertension

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides.

ASSESSING HEMODYNAMIC PERFORMANCES OF SMALL DIAMETER HELICAL GRAFTS: TRANSIENT SIMULATION

The present study numerically simulated the physiological pulsatile flow in helical grafts to increase understanding of its flow mechanism which may contribute to the design of better grafts. The wall-indices like time-averaged wall shear stress (WSS) and oscillatory shear index (OSI), joint with a quantitative index for helical flow by means of Lagrangian approach, were introduced as effective instruments to classify the hemodynamic performance of helical grafts. The simulation suggests that the helical geometry created amplified WSS magnitudes as well as elevated velocities near the wall. The calculated oscillatory shear index (OSI) values were never exceeded to 0.07 which is not considered physiologically significant. In addition, the strong secondary flow in helical graft helped the flow mixing between low-momentum fluid closer to the surface and high-momentum fluid at the center which brought the high-momentum fluid to the surface. Furthermore, Helicity analysis revealed that most of the fluid particles experienced counter-clockwise rotation during the whole cardiac cycle which helps to protect the graft wall from damage by reducing the laterally directed forces and keep flow stability. It concluded that a helical graft provides guaranties for the graft wall surface to get smooth and even washing by the blood and eliminates mechanical trauma to blood cells so that atherosclerotic plaques can hardly form in the graft wall.

Multifaceted role of tocotrienols in cardioprotection supports their structure: function relation

Tocotrienols are a class of vitamin E which modulates several mechanisms associated with cardioprotection, anti-cancer, anti-diabetic, and neuroprotection. Unlike other Vitamin E-like compounds, tocotrienols possess inimitable properties. Quite a lot of studies have determined the cardioprotective abilities of tocotrienols and have been shown to possess novel hypocholesterolemic effects together with an ability to reduce the atherogenic apolipoprotein and lipoprotein plasma levels. In addition, tocotrienol has been suggested to have an antioxidant, anti-thrombotic, and anti-tumor effect indicating that tocotrienol may serve as an effective agent in the prevention and/or treatment of cardiovascular disease and cancer. The bioactivity exhibited is due to the structural characteristics of tocotrienols. Rich sources of tocotrienols which include rice bran, palm oil, and other edible oils exhibit protective effect against cardiovascular disorders. The conclusions drawn from the early literature that vitamin E group of compounds provides an inevitable role in cardioprotection is sustained in many more recent studies.

Resveratrol in cardiovascular health and disease

Resveratrol, initially used for cancer therapy, has shown beneficial effects against most degenerative and cardiovascular diseases from atherosclerosis, hypertension, ischemia/reperfusion, and heart failure to diabetes, obesity, and aging. The cardioprotective effects of resveratrol are associated with its preconditioning-like action potentiated by its adaptive response. During preconditioning, small doses of resveratrol can exert an adaptive stress response, forcing the expression of cardioprotective genes and proteins such as heat shock and antioxidant proteins. Similarly, resveratrol can induce autophagy, another form of stress adaptation for degrading damaged or long-lived proteins, as a first line of protection against oxidative stress. Resveratrol's interaction with multiple molecular targets of diverse intracellular pathways (e.g., action on sirtuins and FoxOs through multiple transcription factors and protein targets) intertwines with those of the autophagic pathway to give support in the modified redox environment after stem cell therapy, which leads to prolonged survival of cells. The successful application of resveratrol in therapy is based upon its hormetic action similar to any toxin: exerting beneficial effects at lower doses and cytotoxic effects at higher doses.

Lipoprotein(a) Is the Best Single Marker in Assessing Unstable Angina Pectoris

This study evaluated whether statin therapy changed a diagnostic validity of lipid and inflammatory markers in ischemic heart disease (IHD) patients. Levels of lipids, lipoproteins, apolipoproteins, inflammatory markers, and atherogenic indexes were determined in 49 apparently healthy men and women, 82 patients having stable angina pectoris (SAP), 80 patients with unstable angina (USAP), and 106 patients with acute ST-elevation myocardial infarction (STEMI) treated or not treated with statins. Diagnostic accuracy of markers was determined by ROC curve analysis. Significantly lower apoA-I in all statin-treated groups and significantly higher apoB in statin-treated STEMI group compared to non-statin-treated groups were observed. CRP showed the best ROC characteristics in the assessment of STEMI patients. Lp(a) is better in the evaluation of SAP and USAP patients, considering that Lp(a) showed the highest area under the curve (AUC). Regarding atherogenic indexes, the highest AUC in SAP group was obtained for TG/apoB and in USAP and STEMI patients for TG/HDL-c. Statins lowered total cholesterol, LDL-c, and TG but fail to normalize apoA-I in patients with IHD.

Rosuvastatin, inflammation, C-reactive protein, JUPITER, and primary prevention of cardiovascular disease--a perspective

The major public health concern worldwide is coronary heart disease, with dyslipidemia as a major risk factor. Statin drugs are recommended by several guidelines for both primary and secondary prevention. Rosuvastatin has been widely accepted because of its efficacy, potency, and superior safety profile. Inflammation is involved in all phases of atherosclerosis, with the process beginning in early youth and advancing relentlessly for decades throughout life. C-reactive protein (CRP) is a well-studied, nonspecific marker of inflammation which may reflect general health risk. Considerable evidence suggests CRP is an independent predictor of future cardiovascular events, but direct involvement in atherosclerosis remains controversial. Rosuvastatin is a synthetic, hydrophilic statin with unique stereochemistry. A large proportion of patients achieve evidence-based lipid targets while using the drug, and it slows progression and induces regression of atherosclerotic coronary lesions. Rosuvastatin lowers CRP levels significantly. The Justification for Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial was designed after the observation that when both low density lipoprotein and CRP were reduced, patients fared better than when only LDL was lowered. Advocates and critics alike acknowledge that the benefits of rosuvastatin in JUPITER were real. After a review, the US Food and Drug Administration extended the indications for rosuvastatin to include asymptomatic JUPITER-eligible individuals with one additional risk factor. The American Heart Association and Centers of Disease Control and Prevention had previously recognized the use of CRP in persons with "intermediate risk" as defined by global risk scores. The Canadian Cardiovascular Society guidelines went further and recommended use of statins in persons with low LDL and high CRP levels at intermediate risk. The JUPITER study focused attention on ostensibly healthy individuals with "normal" lipid profiles and high CRP values who benefited from statin therapy. The backdrop to JUPITER during this period was an increasing awareness of a rising cardiovascular risk burden and imperfect methods of risk evaluation, so that a significant number of individuals were being denied beneficial therapies. Other concerns have been a high level of residual risk in those who are treated, poor patient adherence, a need to follow guidelines more closely, a dual global epidemic of obesity and diabetes, and a progressively deteriorating level of physical activity in the population. Calls for new and more effective means of reducing risk for coronary heart disease are intensifying. In view of compelling evidence supporting earlier and aggressive therapy in people with high risk burdens, JUPITER simply offers another choice for stratification and earlier risk reduction in primary prevention patients. When indicated, and in individuals unwilling or unable to change their diet and lifestyles sufficiently, the benefits of statins greatly exceed the risks. Two side effects of interest are myotoxicity and an increase in the incidence of diabetes.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Resveratrol and cardiovascular health

Resveratrol (3,4',5-trihydroxystilbene) is a member of natural, plant-derived chemicals known as polyphenols and is attracting increased attention due to its diverse health benefits especially in case of cardiovascular disease, cancer, diabetes and neurological problems. Despite impressive gains in diagnosis and treatment, cardiovascular disease (CVD) remains a serious clinical problem and threat to public health. Resveratrol possesses potent antioxidant properties and has been shown to decrease low-density lipoprotein-cholesterol oxidation and platelet aggregation. This compound also possesses a range of additional cardioprotective and vasoprotective properties including antiatherosclerotic and vasorelaxation action. Resveratrol also has the capacity to interact with multiple molecular targets, which involve diverse intracellular pathways. Most well-known is the ability of resveratrol to activate sirtuins, a class of NAD(+)-dependent deacetylase that affect multiple transcription factors and other protein targets. Recently, resveratrol was found to induce autophagy and regenerate myocardial ischemic tissue treated with stem cells. Overall observation indicates that resveratrol has a high therapeutic potentials for the treatment of cardiovascular diseases.

Tissue inhibitor of metalloproteinase-1 is an early marker of acute endothelial dysfunction in a rodent model of venous oxidative injury

Although there are extensive research data regarding arterial endothelial dysfunction, the effects of venous endothelial dysfunction are not well characterized. Matrix metalloproteinases (MMPs) have a defined role in vascular remodeling. MMPs are endopeptidases that are capable of degrading extracellular matrix proteins. We hypothesize that tissue inhibitor of metalloproteinase-1 (TIMP-1) can serve as an indicator of acute venous endothelial dysfunction in a rat model of oxidative injury. The experimental groups evaluated were as follows: rats not undergoing oxidative injury (controls), rats that received rose bengal but no laser (shams), and rats that received both rose bengal and laser illumination, resulting in an oxidative injury. Animals were evaluated at baseline (control, shams) and at 1 hr and 1 day post-oxidative injury. mRNA expression was determined by gene array technology and real-time polymerase chain reaction, plasma and vein wall TIMP-1 protein concentrations were determined by enzyme-linked immunosorbent assay, and vein wall morphometrics (cells/five high-power fields) were performed. B-cell lymphoma 2-like gene expression was upregulated at both 1 hr and 1 day post-injury. TIMP-1 protein and mRNA expression were significantly increased post-oxidative injury. One hour postinjury, vein wall polymorphonuclear leukocytes were present in significant numbers. Our results support the hypothesis that increased expression of TIMP-1 in venous endothelium and plasma may serve as an early indicator of endothelial dysfunction.

Non-conventional markers of atherosclerosis before and after gastric banding surgery

AIMS

Obesity and type 2 diabetes are associated with increased cardiovascular risk and elevation of traditional and non-traditional risk markers. As bariatric surgery reduces overweight and improves metabolic derangement, we examined a cluster of established and emerging cardiovascular risk factors, such as soluble CD40 ligand (sCD40L) and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), which might improve prediction of future cardiovascular events because of their more direct involvement in plaque destabilization.

METHODS AND RESULTS

Obese patients [n = 32, body mass index (BMI) 46.1 +/- 5.9 kg/m(2)] underwent clinical examinations and blood sampling for measurement of glucose and lipid parameters as well as non-traditional cardiovascular risk markers, i.e. high-sensitivity C-reactive protein, plasminogen activator inhibitor-1 (PAI-1), soluble cellular adhesion molecules (CAM), MMP-2, MMP-9, CD40L, and Lp-PLA(2) before and after 1 year following laparoscopic adjustable gastric banding (LAGB), respectively. In patients undergoing LAGB, blood pressure (P < 0.0001) and blood glucose (P = 0.02) were significantly lowered by approximately 16% as well as triglyceride levels by approximately 29% (P = 0.002). In addition to a decrease of the inflammatory and pro-thrombotic marker PAI-1 (P = 0.001), CAMs, and MMP-9 (P = 0.004) were reduced, whereas no change was observed for plasma levels of MMP-2, sCD40L, and Lp-PLA(2) after LAGB, respectively. Individual changes in (ICAM-1) intercellular adhesion molecule-1 (DeltaICAM-1) were related to changes in insulin (Deltafasting insulin) before and after LAGB (r = 0.36 and r = 0.38; both P = 0.04). E-selectin correlated positively with changes in BMI (r = 0.38; P = 0.04 and r = 0.36; P = 0.05), while Lp-PLA(2) concentration was negatively correlated with BMI (r =-0.41; P = 0.02) after 1 year. Changes were comparable in both overweight diabetic and non-diabetic subjects.

CONCLUSION

LAGB not only induced weight loss but also an improvement in the subclinical pro-inflammatory state. However, concentrations of most of the non-traditional risk factors for plaque instability, i.e. MMP-9, sCD40L, and Lp-PLA(2) remained unchanged.

Beneficial effects of resveratrol on atherosclerosis

Atherosclerosis, a progressive disease characterized by the accumulation of lipids and fibrous elements in the arteries, is a most important contributor to cardiovascular diseases. Resveratrol is a naturally occurring phytopolyphenol compound and shows the ability to reduce the risk of cardiovascular diseases. In this review, beneficial effects of resveratrol on the initiation and progression of atherosclerosis, including regulation of vasodilator and vasoconstrictor production, inhibition of oxidative stress/reactive oxygen species generation, anti-inflammation, inhibition of modification of low-density lipoproteins, anti-platelet aggregation, and its abilities to impede progression and modulate complications of atherosclerosis, are discussed.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

Infection-induced inflammatory response of adipocytes in vitro

BACKGROUND

Abdominal obesity plays an important role in the development of insulin resistance, diabetes mellitus and atherosclerosis. The exact pathophysiological mechanisms are unclear but adipocyte dysfunction is thought to be crucial. Infections are associated with the development of atherosclerosis as well as diabetes. In this study we investigated whether adipocytes can be infected and whether this results in production of inflammatory cytokines relevant for the development of atherosclerosis and diabetes.

METHODS

Pre-adipocytes were cultured and differentiated into mature adipocytes in vitro. Adipocytes and pre-adipocytes were incubated with infective and heat-inactivated Chlamydia pneumoniae, cytomegalovirus (CMV), adenovirus (Ad) subtypes 2 and 36, influenza A and respiratory syncitial virus (RSV). After 48 h, adiponectin, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and plasminogen activator inhibitor-1 (PAI-1) were measured in supernatants.

RESULTS

Infection of adipocytes with Ad-36, CMV and RSV resulted in increased IL-6 production from 192+/-22 pg ml(-1) (uninfected) to 1030+/-86 pg ml(-1), 838+/-59 pg ml(-1) and 1241+/-191 pg ml(-1), respectively (all P<0.01 vs control). In addition, Ad-36 infection slightly reduced PAI production in adipocytes (285+/-26.8 ng ml(-1) vs uninfected: 477+/-71.2 ng ml(-1); P=0.05) and pre-adipocytes (709+/-43.3 ng ml(-1) vs uninfected: 1071+/-71.8 ng ml(-1); P<0.01). In contrast, human Ad type 2 did not exert any effect on IL-6 or PAI production. None of the microorganisms induced significant changes in adiponectin and/or TNF-alpha production.

CONCLUSIONS

Adipocytes can be infected with several microorganisms in vitro. Infection of adipocytes with Ad-36, but not Ad-2 leads to increased production of IL-6 which might contribute to chronic low-grade inflammation, a process known to be involved in the development of cardiovascular diseases and type 2 diabetes.

A panel of multiple markers associated with chronic systemic inflammation and the risk of atherogenesis is detectable in asthma and chronic obstructive pulmonary disease

Asthma and chronic obstructive pulmonary disease (COPD) are both lung diseases involving chronic inflammation of the airway. The injury is reversible in asthma whereas it is mostly irreversible in COPD. Both patients of asthma and COPD are known at risk for cardiovascular disease (CVD) and type 2 diabetes (T2DM), nephropathy, and cancer. We measured multiple risk markers for atherogenesis in 55 patients with asthma and 62 patients with COPD. We wanted to know whether risk markers for atherogenesis corresponding to sequence of events of chronic inflammation were also detectable in the airway inflammatory diseases. Elevation of almost all markers involving inflammation of the endothelial cells in the coronary artery were detectable in asthma and COPD involving the inflammation of the epithelial cell lining of the airway. Both the level and % elevation of all markers were found mostly higher in COPD, the more severe form of the lung disease. We believe that these markers are useful for predicting risk of developing clinical complications such as CVD.

Cosmetic liposuction causes only transient elevation of acute inflammatory response and does not advance to oxidative and nitrosative stress

Cosmetic liposuction is a surgical procedure performed on normal nonobese subjects to remove unwanted fat. We are interested to know whether the impact of acute inflammatory response induced by liposuction differs from that of chronic inflammation and whether acute inflammatory response will also advance further and cause oxidative and nitrosative stress leading to various clinical complications. In our investigation we monitored 15 nonobese women prior to liposuction, and one day and one month after the surgery with multiple markers associated with chronic inflammation and oxidative stress. Our results indicate that liposuction causes only a transient elevation of acute inflammatory markers such as interleukin-6 (IL-6), high sensitive C-reactive protein (hCRP), and serum amyloid A (SAA), and a transient decrease of nitric oxide (NO). Apparently the impact of liposuction for normal subjects did not advance beyond acute inflammatory response; there was little change in the levels of markers corresponding to downstream events of chronic systemic inflammation such as adhesion molecules, urinary microalbumin (uMA), homocysteine (Hcy), uric acid (UA), and markers of oxidative stress, including urinary 8-hydroxydeoxyguanosine (8-OhdG) and 3-nitrotyrosine (3NT). It appears that the acute inflammatory response of cosmetic liposuction does not lead to impaired renal function and oxidative and nitrosative damage, which are frequently associated with chronic inflammation.

Development of multiple complications in type 2 diabetes is associated with the increase of multiple markers of chronic inflammation

Patients with type 2 diabetes (T2DM) are known at risk for developing cardiovascular disease (CVD), nephropathy, and cancer. We were interested to find out whether multiple markers associated with chronic inflammation are detectable in patients with T2DM and are increased in patients with T2DM who developed additional clinical complications. A sequence of multiple risk markers for atherogenesis, associated with chronic inflammation, was measured in patients with T2DM before and after the development of clinical complications. We found that multiple clinical complications frequently developed simultaneously in patients with T2DM. At the early stage of T2DM, only low levels and low percent elevations of multiple risk markers were detected. However, both the level and the percent elevation of these markers were found to increase with disease progression and the development of clinical complications. We believe that chronic inflammation not only contributes to the pathogenesis of T2DM but also continues to increase in T2DM patients who are developing additional clinical complications. It appears that these multiple markers are potentially useful not only for monitoring the progression of T2DM but also predicting the risk of developing macro- and microvascular disease, nephropathy, and cancer.

Development and validation of a high-performance liquid chromatography-electrospray mass spectrometry method for the simultaneous determination of 23 eicosanoids

Inflammation is implicated in the pathogenesis of a number of diseases, including cardiovascular disease. Current research is focused on developing assays to search for biomarkers for inflammation. Eicosanoids are the oxidative metabolites of arachidonic acid (eicosatetraenoic acid, AA), a long chain polyunsaturated fatty acid common in Western diets. AA can be oxidized by one of three pathways to form prostaglandins (PGs), leukotrienes (LTs), or a number of hydroxyl and epoxy compounds. These eicosanoids have a variety of physiological functions, including regulating inflammation. We have developed a method utilizing LC-MS to separate and quantitate 23 different eicosanoids from all the three oxidative pathways. The eicosanoids were separated using a gradient elution of acetonitrile with 0.1% formic acid (v/v) and water with 0.1% formic acid (v/v) at a flow rate of 1 mL/min with a Symmetry C18 column (250 mm x 4.6 mm). Deuterated eicosanoids were used as internal standards for quantitation. Mass spectrometric detection was carried out using an Agilent 1100-series LC-MSD with an electrospray ionization interface. Electrospray ionisation (ESI) mass spectra were acquired using negative ionization and selective ion monitoring. The method was validated and shown to be sensitive (LOQ at pg levels for most compounds), accurate (recovery values 75-120%) and precise (R.S.D.<20 for all compounds) with a linear range over several orders of magnitude. The method was applied to rat kidney tissue and shown to be indicative of the eicosanoid levels within a specific organ. The analysis of eicosanoids can provide insight into the inflammatory mechanisms associated with cardiovascular disease.

Establishment of a sandwich ELISA using commercial antibody for plasma or serum 3-nitrotyrosine (3NT). Elevation in inflammatory diseases and complementary between 3NT and myeloperoxidase

BACKGROUND

Amino acid tyrosine residue of a protein can be nitrated to form 3-nitrotyrosine (3NT), which is now being considered as a marker of inflammation, oxidative and nitrosative stress.

METHOD

An in-house ELISA has been established using the same commercial antibody for both binding and detection of 3NT containing proteins.

RESULTS

The sensitivity of the in-house ELISA was 1.8 nmol/l. The imprecision was <10% at all concentrations. The in-house assay correlates well with a commercial kit (r=0.89). In addition to EDTA plasma, we found that both heparinized plasma and serum can also be used to quantify 3NT concentration. Using the in-house ELISA we have detected increased concentrations of 3NT in diseases known to be associated with inflammation and also in subjects with polyps. As marker of oxidative stress and inflammation, both 3NT and myeloperoxidase are complementary to each other in test sensitivity.

CONCLUSION

This ELISA can be used in the clinical laboratories to monitor the inflammatory disease activity and assess early risks that are associated with inflammation, oxidative and nitrosative stress.

Alpha-Tocopherol counteracts ritonavir-induced proinflammatory cytokines expression in differentiated THP-1 cells

Treatment of HIV-infected individuals with HIV protease inhibitor (HPI) drugs has significantly increased their life span. However, one of the side effects of HPI drugs is the development of premature atherosclerosis, whose molecular pathogenesis remains unclear. Previously we have reported that alpha-tocopherol (alpha-T) normalizes CD36 overexpression induced by ritonavir treatment and reduces oxLDL uptake in THP-1 cells. Since inflammation is a major player in the pathogenesis of atherosclerosis, we hypothesized that HPI drugs, such as ritonavir, increase proinflammatory cytokines synthesis and that alpha-T supplementation counteracts this effect by suppressing proinflammatory cytokines levels. Here, we report that after differentiating THP-1 cells to macrophages, ritonavir treatment (10 microg/mL) significantly increases expression of proinflammatory cytokines, IL-6, MCP-1 and IL-8, at both mRNA and protein levels. This ritonavir-induced effect is significantly suppressed by treatment of THP-1/macrophages with 50 muM alpha-T. We conclude that ritonavir can induce proinflammatory cytokines synthesis in THP-1/macrophages, which might be associated with the development of premature atherosclerosis in ritonavir-treated patients and that this effect is prevented by alpha-T.

Thrombin generation by activated factor VII on platelet activated by different agonists. Extending the cell-based model of hemostasis

Background

Platelet activation is crucial in normal hemostasis. Using a clotting system free of external tissue factor, we investigated whether activated Factor VII in combination with platelet agonists increased thrombin generation (TG) in vitro.

Methods and results

TG was quantified by time parameters: lag time (LT) and time to peak (TTP), and by amount of TG: peak of TG (PTG) and area under thrombin formation curve after 35 minutes (AUC→_35min) in plasma from 29 healthy volunteers using the calibrated automated thrombography (CAT) technique. TG parameters were measured at basal conditions and after platelet stimulation by sodium arachidonate (AA), ADP, and collagen (Col). In addition, the effects of recombinant activated FVII (rFVIIa) alone or combined with the other platelet agonists on TG parameters were investigated. We found that LT and TTP were significantly decreased (p < 0.05) and PTG and AUC→_35min were significantly increased (p < 0.05) in platelet rich plasma activated with AA, ADP, Col, and rFVIIa compared to non-activated platelet rich plasma from normal subjects (p = 0.01). Furthermore platelet rich plasma activated by the combined effects of rFVIIa plus AA, ADP or Col had significantly reduced LT and TTP and increased AUC→_35min (but not PTG) when compared to platelet rich plasma activated with agonists in the absence of rFVIIa.

Conclusion

Platelets activated by AA, ADP, Col or rFVIIa triggered TG. This effect was increased by combining rFVIIa with other agonists. Our intrinsic coagulation system produced a burst in TG independent of external tissue factor activity an apparent hemostatic effect with little thrombotic capacity. Thus we suggest a modification in the cell-based model of hemostasis.

Helical flow as fluid dynamic signature for atherogenesis risk in aortocoronary bypass. A numeric study

The main purpose of the study was to verify if helical flow, widely observed in several vessels, might be a signature of the blood dynamics of vein graft anastomosis. We investigated the existence of a relationship between helical flow structures and vascular wall indexes of atherogenesis in aortocoronary bypass models with different geometric features. In particular, we checked for the existence of a relationship between the degree of helical motion and the magnitude of oscillating shear stress in conventional hand-sewn proximal anastomosis. The study is based on the numerical evaluation of four bypass geometries that are attached to a simplified computer representation of the ascending aorta with different angulations relative to aortic outflow. The finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. A quantitative method was applied to evaluate the level of helicity in the flow field associated with the four bypass models under investigation. A linear inverse relationship (R = -0.97) was found between the oscillating shear index and the helical flow index for the models under investigation. The results obtained support the hypothesis that an arrangement of the flow field in helical patterns may elicit damping in wall shear stress temporal gradients at the proximal graft. Accordingly, helical flow might play a significant role in preventing plaque deposition or in tuning the mechanotransduction pathways of cells. Therefore, results confirm that helical flow constitutes an important flow signature in vessels, and its strength as a fluid dynamic index (for instance in combination with magnetic resonance imaging flow visualization techniques) for risk stratification, in the activation of both mechanical and biological pathways leading to fibrointimal hyperplasia.

Linking inflammation and atherogenesis: Soluble markers identified for the detection of risk factors and for early risk assessment

Increasing evidence has shown that atherogenesis is not only caused by hypercholesterolemia. Several risk factors including abdominal obesity, dyslipidemia, hyperglycemia, bacterial and viral infection, hyperhomocysteinemia have been identified recently, all mediated through inflammation, which can lead to atherosclerosis. Several events have also been identified to be involved in the overall inflammation reaction in the blood vessel which include endothelium dysfunction, expression of adhesion molecules, recruitment of leukocytes to the injured endothelium, migration of monocytes to the arterial intima, and transformation of monocytes to macrophages. In order to facilitate the assessment of early risk for atherogenesis we have made an effort in this review to identify soluble markers that will allow the detection of these risk factors and the identification of associated inflammation events. Since early risks for atherogenesis are largely preventable with dietary modification and lifestyle changes, capable of detecting early risks by monitoring soluble risk markers is conceivably important for asymptomatic individuals to avoid serious or fatal consequences of atherosclerosis. These soluble markers should also be useful for monitoring the effectiveness of intervention and for the identification of therapeutic targets.

Increased levels of C-reactive protein and fibrinogen influence the risk of vascular events in patients with NIDDM

AIM

To evaluate the predictive role of hs-CRP and fibrinogen for cardio- and cerebrovascular events in a population of patients with type 2 diabetes.

METHODS

We studied 156 patients with type 2 diabetes, mean age 66+10 years, and 156 sex and age matched control subjects. Patients underwent physical examination, EKG, measurement of body mass index and blood pressure. A blood sample was drawn to evaluate glycaemia, total and HDL/LDL cholesterol, triglycerides, high sensitive C-reactive protein (hs-CRP), fibrinogen. Finally, patients underwent an ecocolordoppler examination of the common carotid arteries until the bifurcation. In a follow-up of 5+/-1.2 years we evaluated the following events: transient ischemic attack, ischemic stroke, stable or unstable angina, acute myocardial infarction, critical limb ischemia and cardiovascular death.

RESULTS

During the follow-up the prevalence of fatal (p<0.05) and non fatal events (p<0.0001) was higher in patients with diabetes in comparison with controls. The variables independently associated with non fatal events were: fibrinogen (p<0.0001), presence of asymptomatic carotid lesion (p<0.005), obesity (p<0.05) and plasma levels of hs-CRP (p<0.05), while fibrinogen (p<0.001) and age were (p<0.05) independently associated with fatal events.

CONCLUSION

Our data show that in patients with diabetes mellitus, that in the follow-up the presence of high plasma levels of hs-CRP and fibrinogen are predictive for fatal or non fatal events.

Early clinical results of St. Jude Medical Symmetry aortic connector

An automated anastomosis device named St. Jude Medical symmetry aortic connector has been used worldwide for off-pump coronary artery bypass grafting. However, early graft obstruction was recently reported, and its predictors should be clarified. From April 2002 to March 2004, 38 patients in our institution underwent off-pump coronary artery bypass grafting using the St. Jude Medical Symmetry aortic connector for saphenous vein graft (SVG) procedures; measurement of intraoperative graft flow and postoperative coronary angiography was performed. Early SVG events occurred in 9 (24%) patients: 8 occlusion cases and 1 case of stenosis. Predictors of early SVG events were assessed from a comparative study. Univariate logistic regression identified hyperlipidemia as the only significant predictor of early SVG events (P = 0.02, odds ratio 7.78). Lower SVG flow rate and poor ejection fraction did not show statistical significance (P = 0.09, odds ratio 1.09 and P = 0.09, odds ratio 0.96). The SVG event rate was much higher for the left circumflex branch compared with other locations (31% vs. 9%, P = 0.03) and decreased with increasing aortic connector size (small, 32%; median, 14%; large, 0%). Multivariate analysis did not identify a predictor of SVG events. The aortic connector is associated with a high incidence of early SVG events. Patients should be cautiously selected and the procedure should not be used for left anterior descending coronary artery or culprit lesions.

Interleukin-1 Receptor Signaling Mediates Atherosclerosis Associated With Bacterial Exposure and/or a High-Fat Diet in a Murine Apolipoprotein E Heterozygote Model

BACKGROUND

Current data demonstrate that progressive atherosclerosis is associated with activation of the inflammatory process, as evidenced by systemic elevations of molecules such as tumor necrosis factor, interleukin (IL)-6, and IL-1. It has been postulated that inflammatory events within an atherogenic lesion are induced by oxidized LDL. Recent evidence suggests that infectious agents, including those that cause periodontal disease, may also play an important role. Studies presented here tested the hypothesis that IL-1 receptor (IL-1R1) signaling plays a crucial role in bacteria- and/or high-fat diet (HFD)-enhanced atherogenesis.

METHODS AND RESULTS

Ten-week-old ApoE+/- mice lacking either 1 IL-1R1 allele (ApoE+/-/IL-1R1+/-) or 2 IL-1R1 alleles (ApoE+/-/IL-1R1-/-) fed either an HFD or regular chow were inoculated intravenously with live Porphyromonas gingivalis (P gingivalis) (10(7) CFU), an important periodontal pathogen, or vehicle once per week for 14 or 24 consecutive weeks. Histomorphometry of plaque cross-sectional area in the proximal aortas, en face measurement of plaque area over the aortic trees, and ELISA for systemic proinflammatory mediators were performed. Atherosclerotic lesions of proximal aortas and aortic tree were substantially reduced in ApoE+/-/IL-1R1-/- mice than in ApoE+/-/IL-1R1+/- mice challenged with P gingivalis. At 24 weeks after P gingivalis inoculation, proximal aortic lesion size quantified by histomorphometry was 5-fold-reduced in chow-fed ApoE+/-/IL-1R1-/- mice than in ApoE+/-/IL-1R1+/- mice (P<0.05). In the HFD group, ApoE+/-/IL-1R1-/- mice exhibited marked attenuation of the progression of atherosclerotic lesions (78% to 97%), with and without P gingivalis inoculation (P<0.05).

CONCLUSIONS

Ablation of IL-1R1 under P gingivalis challenge and/or an HFD reduced the progression of atherosclerotic plaques. These results indicate that IL-1 plays a crucial role in bacteria- and/or HFD-enhanced atherogenesis.

Flow dynamics of the St Jude Medical Symmetry aortic connector vein graft anastomosis do not contribute to the risk of acute thrombosis

BACKGROUND

The efficacy of the St Jude Medical Symmetry aortic connector (St Jude Medical, Inc, St Paul, Minn) for coronary artery bypass is currently debated. Potential drawbacks are the biocompatibility of the endoluminal device, the need for graft manipulation during the procedure, and the 90 degrees offset of the vein graft from the ascending aorta, which may induce graft kinking and abnormal fluid dynamics. In this article, a computational approach was designed to investigate the fluid dynamics pattern at the proximal graft.

METHODS

Four models of hand-sewn anastomoses and two models of automated anastomoses were constructed; a finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. The anastomosis geometry performance was analyzed by calculating time-averaged wall shear stress and the oscillating shear index at the toe and heel regions of the proximal graft.

RESULTS

Time-averaged wall shear stress was significantly lower in the hand-sewn anastomosis models than in the two models that simulated the use of the aortic connector (0.38 +/- 0.07 Pa vs 1.32 +/- 0.4 Pa). Higher oscillating shear index values were calculated in the hand-sewn anastomosis models (0.15 +/- 0.02 Pa vs 0.06 +/- 0.02 Pa).

CONCLUSIONS

Automated anastomosis geometry is associated with less critical fluid dynamics than with conventional hand-sewn anastomosis: the shape of the proximal graft induces more physiological wall shear stresses and less oscillating flow, suggesting a lower risk of atherosclerotic plaque and intimal hyperplasia as compared with conventional anastomosis geometry. Therefore, the reported early thrombosis and late failure of the St Jude Medical aortic connector anastomoses are not related to unfavorable fluid dynamics.