Cyclooxygenase-2 is widely expressed in atherosclerotic lesions affecting native and transplanted human coronary arteries and colocalizes with inducible nitric oxide synthase and nitrotyrosine particularly in macrophages

The Evolving Role of Dendritic Cells in Atherosclerosis

Atherosclerosis, a major contributor to cardiovascular morbidity and mortality, is characterized by chronic inflammation of the arterial wall. This inflammatory process is initiated and maintained by both innate and adaptive immunity. Dendritic cells (DCs), which are antigen-presenting cells, play a crucial role in the development of atherosclerosis and consist of various subtypes with distinct functional abilities. Following the recognition and binding of antigens, DCs become potent activators of cellular responses, bridging the innate and adaptive immune systems. The modulation of specific DC subpopulations can have either pro-atherogenic or atheroprotective effects, highlighting the dual pro-inflammatory or tolerogenic roles of DCs. In this work, we provide a comprehensive overview of the evolving roles of DCs and their subtypes in the promotion or limitation of atherosclerosis development. Additionally, we explore antigen pulsing and pharmacological approaches to modulate the function of DCs in the context of atherosclerosis.

Preventive effects of chemical drugs on recurrence of colorectal adenomas: systematic review and Bayesian network meta-analysis

BACKGROUND

The onset of colorectal adenomas (CRAs) is significantly associated with colorectal cancer. The preventive effects of chemical drugs on the recurrence of CRAs have been evaluated in a large number of randomized controlled trials (RCTs). However, there are still uncertainties about the relative effectiveness of such chemical drugs.

METHODS

We searched relevant RCTs published in six databases up to February 2023. The quality of the included studies was assessed by using the Cochrane risk of bias assessment tool and Review Manager 5.4. Pairwise comparison and network meta-analysis (NMA) were conducted using RStudio to compare the effects of chemical drugs on the recurrence of CRAs.

RESULTS

Forty-five high-quality RCTs were included. A total of 35 590 (test group: 20 822; control group: 14 768) subjects with a history of CRAs have been enrolled and randomized to receive placebo treatment or one of 24 interventions. Based on surface under the cumulative ranking values and NMA results, difluoromethylornithine (DFMO) + Sulindac significantly reduced the recurrence of CRAs, followed by berberine and nonsteroidal antiinflammatory drugs.

CONCLUSION

DFMO + Sulindac is more effective in reducing the recurrence of CRAs but has a high risk of adverse events. Considering drug safety, tolerance, and compliance, berberine has a brighter prospect of clinical development. However, further studies are needed to verify our findings.

Immunomodulation by tramadol combined with acetaminophen or dexketoprofen: In vivo animal study

Among other functions, macrophages remove foreign particles, including medications, from the circulation, making them an important target for immunomodulatory molecules. Currently, growing evidence suggests that analgesics affect the activity of immune cells not directly related to pain, and thus may induce unwanted immunosuppression in patients at risk. However, the immunomodulatory effects resulting from macrophage targeting by these drugs are understudied. Therefore, the current study investigated the immune effects induced in healthy mice by repeated administration of tramadol alone or in combination with acetaminophen or dexketoprofen. We observed that drug administration decreased the percentage of infiltrating macrophages in favor of resident macrophages in peritoneal exudates. While all drugs reduced the number of infiltrating macrophages that phagocytosed sheep red blood cells (SRBC), their administration increased the effectiveness of phagocytosis, and treatment with acetaminophen with or without tramadol elevated the expression of MHC class II by Mac3+ macrophages. Interestingly, SRBC-pulsed macrophages from mice treated with tramadol combined with acetaminophen potently activated SRBC-specific B cells in humoral response, and administration of these drugs to recipients of contact hypersensitivity effector cells augmented the resulting cellular immune response. In addition, tramadol administered alone or with dexketoprofen enhanced the spontaneous release of pro-inflammatory cytokines by macrophages. Our current research findings demonstrate that tramadol therapy in combination with acetaminophen or dexketoprofen has a relatively low risk of causing immunosuppressive side effect because the drugs slightly reduce the inflammatory reaction of macrophages but do not impair their ability to activate the adaptive immune responses.

Analysis of Sex-Specific Prostanoid Production Using a Mouse Model of Selective Cyclooxygenase-2 Inhibition

Background:

Prostanoids are a family of lipid mediators formed from arachidonic acid by cyclooxygenase enzymes and serve as biomarkers of vascular function. Prostanoid production may be different in males and females indicating that different therapeutic approaches may be required during disease.

Objectives:

We examined sex-dependent differences in COX-related metabolites in genetically modified mice that produce a cyclooxygenase-2 (COX2) enzyme containing a tyrosine 385 to phenylalanine (Y385F) mutation. This mutation renders the COX2 enzyme unable to form a key intermediate radical required for complete arachidonic acid metabolism and provides a model of selective COX2 inhibition.

Design and Methods:

Mice heterozygous for the Y385F mutation in COX2 were mated to produce cohorts of wild-type, heterozygous, and COX2 mutant mice. We investigated whether the genotype distribution followed Mendelian genetics and studied whether sex-specific differences could be found in certain prostanoid levels measured in peritoneal macrophages and in urinary samples.

Results:

The inheritance of the COX2 mutation displayed a significant deviation with respect to Mendel’s laws of genetics, with a lower-than-expected progeny of weaned COX2 mutant pups. In macrophages, prostaglandin E2 (PGE2) production following lipopolysaccharide (LPS) and interferon gamma (IFNγ) stimulation was COX2-dependent in both males and females, and data indicated that crosstalk between the nitric oxide (NO) and COX2 pathways may be sex specific. We observed significant differences in urinary PGE2 production by male and female COX2 mutant mice, with the loss of COX2 activity in male mice decreasing their ability to produce urinary PGE2. Finally, female mice across all 3 genotypes produced similar levels of urinary thromboxane (measured as 11-dehydro TxB2) at significantly higher levels than males, indicating a sex-related difference that is likely COX1-derived.

Conclusions:

Our findings clearly demonstrate that sex-related differences in COX-derived metabolites can be observed, and that other pathways (such as the NO pathway) are affected.

Two-Photon, Ratiometric, Quantitative Fluorescent Probe Reveals Fluctuation of Peroxynitrite Regulated by Arginase 1

Peroxynitrite, a transient reactive oxygen species (ROS), is believed to play a deleterious role in physiological processes. Herein, we report a two-photon ratiometric fluorescent probe that selectively reacts with peroxynitrite yielding a >200-fold change upon reaction. The probe effectively visualized fluctuations in peroxynitrite generation by arginase 1 in vivo and in vitro. This provides evidence that arginase 1 is a critical regulator of peroxynitrite.

Sleep disorders and vascular responsiveness in patients with rheumatoid arthritis

BACKGROUND

Rheumatoid arthritis (RA) is the most common systemic autoimmune disease characterized by chronic systemic inflammation. Half of the deaths of patients with RA are due to cardiovascular diseases (CVD), considered to be 1.5 to -2.0-fold that in the general population. Patients with RA also experience poor sleep, which by itself is associated with endothelial dysfunction, CVD events and sudden death. Our aim was to study the mechanistic pathways and the correlations between sleep efficiency and vascular reactivity of patients with RA.

METHODS AND RESULTS

A prospective study that evaluated quality of sleep using ACTi Graphs, vascular inflammation and endothelial function of 18 patients with RA. Inflammation was studied by levels of E-selectin, intercellular adhesion molecule 1 (ICAM-1) and NO in serum. Endothelial function was studied using the brachial artery plethysmography method. Eighteen RA patients (aged 57.56 ± 13.55 years; 16 women) with a long-standing active RA: Eight patients had impaired sleep efficiency and 10 had a good sleep efficiency. Those who had an impaired sleep had larger baseline diameters of the brachial artery (0.39 ± 0.08 cm vs. 0.32 ± 0.04 cm; P = 0.02). Negative correlations were found between baseline brachial artery diameter and sleep efficiency (P = 0.01), and with NO level (P = 0.04). Stepwise regression found that brachial artery diameter at baseline and NO level could predict sleep efficiency (r²  = 0.543, P = 0.01).

CONCLUSION

Vascular reactivity could predict quality of sleep in patients with RA. Quality of sleep may serve as an independent CVD risk factor in patients with RA.

Organosulfur Compounds: A Review of Their Anti-inflammatory Effects in Human Health

Phytonutrients are widely recognized for providing protective human health benefits. Among the phytonutrients, epidemiological and experimental studies show that dietary organosulfur compounds (OSC) play a significant role in preventing various human pathological progressions, including chronic inflammation, by decreasing inflammatory mediators such as nitric oxide (NO), prostaglandin (PG)E₂, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-17, which are all typical hallmarks of inflammation. Evidence supports OSC in reducing the expression of these markers, thereby attenuating chronic inflammatory processes. Nuclear factor-kappa B (NF-κB) is a key regulating factor during inflammation, and novel evidence shows that OSC downregulates this transcriptional factor, thus contributing to the anti-inflammatory response. In vitro and in vivo studies show that inflammation is mechanistically linked with acute and chronic pathological conditions including cancer, diabetes, obesity, neural dysfunction, etc. Furthermore, a considerable number of experiments have demonstrated that the anti-inflammatory properties of OSC occur in a dose-dependent manner. These experiments also highlight indirect mechanisms as well as potent co-functions for protective roles as antioxidants, and in providing chemoprotection and neuroprotection. In this brief review, we provided an overview of the anti-inflammatory effects of OSC and elucidated probable mechanisms that are associated with inflammation and chronic disorders.

Role of reactive oxygen species in atherosclerosis: Lessons from murine genetic models

Atherosclerosis is a multifactorial chronic and inflammatory disease of medium and large arteries, and the major cause of cardiovascular morbidity and mortality worldwide. The pathogenesis of atherosclerosis involves a number of risk factors and complex events including hypercholesterolemia, endothelial dysfunction, increased permeability to low density lipoproteins (LDL) and their sequestration on extracellular matrix in the intima of lesion-prone areas. These events promote LDL modifications, particularly by oxidation, which generates acute and chronic inflammatory responses implicated in atherogenesis and lesion progression. Reactive oxygen species (ROS) (which include both free radical and non-free radical oxygen intermediates), play a key-role at each step of atherogenesis, in endothelial dysfunction, LDL oxidation, and inflammatory events involved in the initiation and development of atherosclerosis lesions. Most advanced knowledge supporting the "oxidative theory of atherosclerosis" i.e. the nature and the cellular sources of ROS and antioxidant defences, as well as the mechanisms involved in the redox balance, is based on the use of genetically engineered animals, i.e. transgenic, genetically modified, or altered for systems producing or neutralizing ROS in the vessels. This review summarizes the results obtained from animals genetically manipulated for various sources of ROS or antioxidant defences in the vascular wall, and their relevance (advance or limitation), for understanding the place and role of ROS in atherosclerosis.

Cardio-renal safety of non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most widely used therapeutic class in clinical medicine. These are sub-divided based on their selectivity for inhibition of cyclooxygenase (COX) isoforms (COX-1 and COX-2) into: (1) non-selective (ns-NSAIDs), and (2) selective NSAIDs (s-NSAIDs) with preferential inhibition of COX-2 isozyme. The safety and pathophysiology of NSAIDs on the renal and cardiovascular systems have continued to evolve over the years following short- and long-term treatment in both preclinical models and humans. This review summarizes major learnings on cardiac and renal complications associated with pharmaceutical inhibition of COX-1 and COX-2 with focus on preclinical to clinical translatability of cardio-renal data.

Association of COX2 -765G>C promoter polymorphism and coronary artery disease in Korean population

BACKGROUND

Cyclooxygenase-2 (COX2) plays a role in the formation of prostaglandins, which contribute to the inflammation involved in atherosclerosis. However, the role of the COX2 -765G>C polymorphism in susceptibility to coronary artery disease (CAD) is controversial.

OBJECTIVE

To identify the association between COX2 -765G>C polymorphism with CAD risk in Korean patients. We recruited 622 patients who were diagnosed to have coronary artery disease and 202 controls who did not have history and vascular disease risk factors.

METHODS

Using polymerase chain reaction-restriction fragment length polymorphism, the COX2 -765G>C polymorphism was analyzed in 622 Korean patients who received percutaneous coronary intervention and in 202 healthy control subjects.

RESULTS

The GC+CC genotype frequencies of the -765G>C polymorphism were significantly different between the CAD and control groups. The COX2 -765G>C polymorphism showed peculiar associations with CAD according to the presence of hyperlipidemia and plasma folate levels. However, there were no associations between the -765G>C polymorphism and the rates of hypertension, diabetes mellitus, or homocysteine levels.

CONCLUSION

This study suggests that the COX2 -765G>C polymorphism is a possible genetic determinant for the risk of CAD, and an individual risk factor in Koreans. Thus, further association studies between the COX2 polymorphism and atherosclerotic-related diseases such as cerebrovascular or cardiovascular diseases in other races or ethnicities will be needed.

Dose-Effect of Irbesartan on Cyclooxygenase-2 and Matrix Metalloproteinase-9 Expression in Rabbit Atherosclerosis

Irbesartan has previously shown antiatherosclerotic effects on human carotid atherosclerotic plaques. Our study aimed to assess the dose-effect of irbesartan on cyclooxygenase-2 (COX-2) and matrix metalloproteinase-9 (MMP-9) in rabbit atherosclerotic aorta. New Zealand rabbits were randomly divided into 6 groups: normal control (NC), high cholesterol (HC), low-dose (10 mg·kg·day), medium-dose (20 mg·kg·d), and high-dose (30 mg·kg·d) irbesartan and celecoxib (20 mg·kg·d). Except for the NCs, rabbits were fed a HC diet for 14 weeks to induce atherosclerosis. Aortic atherosclerotic lesions and messenger RNA and protein expression of COX-2, MMP-9, and nuclear factor-κB (NF-κB) were subsequently measured. The surface area of aortic atherosclerotic lesions was visibly larger in the HC group than in NCs (P < 0.01), but showed considerable reduction with medium- and high-dosage irbesartan and celecoxib treatments (P < 0.01). In medium- and high-dosage irbesartan and celecoxib groups, COX-2 and MMP-9 expression and NF-κB activity were significantly lower than in the high-cholesterol group (P < 0.01). No significant differences in treatment effects were observed between the high-dosage irbesartan and celecoxib groups (P > 0.05). Our results indicate that medium and high doses of irbesartan and celecoxib have antiatherosclerotic effects in aortic plaques via inhibition of COX-2 and MMP-9 by suppressing NF-κB activation. High-dose irbesartan has effects similar to celecoxib.

The immunophenotype of decidual macrophages in acute atherosis

PROBLEM

Acute atherosis is a uteroplacental arterial lesion that is associated with pregnancy complications such as preeclampsia and preterm birth, the latter being the leading cause of perinatal morbidity and mortality worldwide. However, the immunobiology of acute atherosis is poorly understood.

METHOD OF STUDY

Placental basal plate samples were collected from women who delivered with (n = 11) and without (n = 31) decidua basalis lesions of acute atherosis. Multicolor flow cytometry was used to quantify M1- and M2-like macrophage subsets and the expression of iNOS and IL-12 by decidual macrophages. Multiplex fluorescence staining and phenoptics were performed to localize M1-, MOX-, and Mhem-like macrophages in the decidual basalis.

RESULTS

Macrophages displayed diverse phenotypes in the decidua basalis with acute atherosis. M2-like macrophages were the most abundant subset in the decidua; yet, this macrophage subset did not change with the presence of acute atherosis. Decidual M1-like macrophages were increased in acute atherosis, and such macrophages displayed a pro-inflammatory phenotype, as indicated by the expression of iNOS and IL-12. Decidual M1-like pro-inflammatory macrophages were localized near both transformed and non-transformed vessels in the decidua basalis with acute atherosis. MOX and Mhem macrophages were also identified near transformed vessels in the decidua basalis with acute atherosis. Finally, monocyte-like cells were present on the vessel wall of non-transformed decidual vessels, indicating a possible intravascular source for macrophages in acute atherosis.

CONCLUSION

Decidual macrophages display different phenotypes, namely M1-like, M2-like, MOX, and Mhem subsets. Yet, pro-inflammatory macrophages are enriched in the decidua basalis with acute atherosis. These findings provide a molecular foundation for future mechanistic inquiries about the role of pro-inflammatory macrophages in the pathogenesis of acute atherosis.

Sources of Vascular Nitric Oxide and Reactive Oxygen Species and Their Regulation

Nitric oxide (NO) is a small free radical with critical signaling roles in physiology and pathophysiology. The generation of sufficient NO levels to regulate the resistance of the blood vessels and hence the maintenance of adequate blood flow is critical to the healthy performance of the vasculature. A novel paradigm indicates that classical NO synthesis by dedicated NO synthases is supplemented by nitrite reduction pathways under hypoxia. At the same time, reactive oxygen species (ROS), which include superoxide and hydrogen peroxide, are produced in the vascular system for signaling purposes, as effectors of the immune response, or as byproducts of cellular metabolism. NO and ROS can be generated by distinct enzymes or by the same enzyme through alternate reduction and oxidation processes. The latter oxidoreductase systems include NO synthases, molybdopterin enzymes, and hemoglobins, which can form superoxide by reduction of molecular oxygen or NO by reduction of inorganic nitrite. Enzymatic uncoupling, changes in oxygen tension, and the concentration of coenzymes and reductants can modulate the NO/ROS production from these oxidoreductases and determine the redox balance in health and disease. The dysregulation of the mechanisms involved in the generation of NO and ROS is an important cause of cardiovascular disease and target for therapy. In this review we will present the biology of NO and ROS in the cardiovascular system, with special emphasis on their routes of formation and regulation, as well as the therapeutic challenges and opportunities for the management of NO and ROS in cardiovascular disease.

Up-regulation of COX-2 and mPGES-1 by 27-hydroxycholesterol and 4-hydroxynonenal: A crucial role in atherosclerotic plaque instability

Atherosclerosis is currently understood to be mainly the consequence of a complicated inflammatory process at the different stages of plaque development. Among the several inflammatory molecules involved, up-regulation of the functional cyclooxygenase 2/membrane-bound prostaglandin E synthase 1 (COX-2/mPGES-1) axis plays a key role in plaque development. Excessive production of oxidized lipids, following low-density lipoprotein (LDL) oxidation, is a characteristic feature of atherosclerosis. Among the oxidized lipids of LDLs, the oxysterol 27-hydroxycholesterol (27-OH) and the aldehyde 4-hydroxynonenal (HNE) substantially accumulate in the atherosclerotic plaque, contributing to its progression and instability through a variety of processes. This study shows that 27-OH and HNE promote up-regulation of both the inducible enzymes COX-2 and mPGES-1, leading to increased production of prostaglandin (PG) E₂ and inducible nitric oxide synthase, and the subsequent release of nitric oxide in human promonocytic U937 cells. The study also examined the potential involvement of the functionally coupled COX-2/mPGES-1 in enhancing the production of certain pro-inflammatory cytokines and of matrix metalloproteinase 9 by U937 cells. This enhancement is presumably due to the induction of PGE₂ synthesis, as a result of the up-regulation of the COX-2/mPGES-1, stimulated by the two oxidized lipids, 27-OH and HNE. Induction of PGE₂ synthesis might thus be a mechanism of plaque instability and eventual rupture, contributing to matrix metalloproteinase production by activated macrophages.

Mechanisms of Dysfunction in the Aging Vasculature and Role in Age-Related Disease

Advancing age promotes cardiovascular disease (CVD), the leading cause of death in the United States and many developed nations. Two major age-related arterial phenotypes, large elastic artery stiffening and endothelial dysfunction, are independent predictors of future CVD diagnosis and likely are responsible for the development of CVD in older adults. Not limited to traditional CVD, these age-related changes in the vasculature also contribute to other age-related diseases that influence mammalian health span and potential life span. This review explores mechanisms that influence age-related large elastic artery stiffening and endothelial dysfunction at the tissue level via inflammation and oxidative stress and at the cellular level via Klotho and energy-sensing pathways (AMPK [AMP-activated protein kinase], SIRT [sirtuins], and mTOR [mammalian target of rapamycin]). We also discuss how long-term calorie restriction-a health span- and life span-extending intervention-can prevent many of these age-related vascular phenotypes through the prevention of deleterious alterations in these mechanisms. Lastly, we discuss emerging novel mechanisms of vascular aging, including senescence and genomic instability within cells of the vasculature. As the population of older adults steadily expands, elucidating the cellular and molecular mechanisms of vascular dysfunction with age is critical to better direct appropriate and measured strategies that use pharmacological and lifestyle interventions to reduce risk of CVD within this population.

Effects of Watermelon Powder and l-arginine Supplementation on Azoxymethane-Induced Colon Carcinogenesis in Rats

Diets high in fruits and vegetables may help prevent colorectal cancer (CRC). Watermelon consumption may reduce CRC risk due to its concentration of l-citrulline and its role in endothelial nitric oxide (NO) production. Research suggests that increased NO levels have tumoricidal effects. The purpose of this study was to determine the effects of watermelon powder supplementation on aberrant crypt foci (ACF) formation, precancerous lesions, and expression of genes associated with colon carcinogenesis. Thirty-two male Sprague-Dawley rats were assigned into three groups: control, 0.36% l-arginine, or 0.5% watermelon powder and injected with azoxymethane (15 mg/kg body weight). Both l-arginine and watermelon powder groups exhibited lower total numbers of ACF and high multiplicity ACF (P < 0.01). The watermelon powder group exhibited higher NO levels and lower 8-hydroxyguanosine DNA damage (P < 0.05). Watermelon powder and l-arginine downregulated 8-oxoguanine DNA glycosylase gene expression and upregulated O⁶-methylguanine DNA methyltransferase gene expression (P < 0.05). Cyclooxgenase-2 gene expression was lower for rats fed with watermelon powder (P < 0.05). These results suggest that watermelon powder or l-arginine supplementation may reduce the risk of colon cancer by suppressing ACF formation through lowering oxidative DNA damage and inflammation, modulating DNA repair enzyme expression, and/or enhancing NO production.

MicroRNA-381 regulates the occurrence and immune responses of coronary atherosclerosis via cyclooxygenase-2

The present study aimed to measure the levels of microRNA-381 (miR-381) in the plaque tissues, peripheral blood mononuclear cells (PBMCs) and serum of patients with coronary atherosclerosis. In addition, the regulatory mechanisms of miR-381 and cyclooxygenase (COX)-2 in coronary atherosclerosis were investigated. A total of 36 patients with coronary atherosclerosis who received coronary endarterectomy at Linyi People's Hospital and Junan Hospital of Traditional Chinese Medicine (Linyi, China) between January 2013 and June 2016 were enrolled into the present study, while 39 healthy subjects were included as the control group. Peripheral blood was collected form all patients and healthy subjects. Plaque tissues were resected from patients with coronary atherosclerosis and adjacent artery intimal tissues were resected as the control tissues. Using quantitative polymerase chain reaction, the levels of miR-381 and COX-2 mRNA in the plaque tissues, PBMCs and serum were determined. In addition, COX-2 protein expression in the plaque tissues and PBMCs was measured by western blotting, while enzyme-linked immunosorbent assay was utilized to examine the protein content in the serum. To identify the direct interaction between miR-381 and COX-2 mRNA, dual-luciferase reporter assay was also conducted. The levels of COX-2 mRNA and protein in the plaque tissues, PBMCs and serum of patients with coronary atherosclerosis were significantly elevated compared with those in the corresponding control groups. However, the expression of miR-381 was significantly reduced in the coronary atherosclerosis patients. Dual-luciferase reporter assay revealed that miR-381 was able to directly target the 3'-untranslated region of COX-2 mRNA to regulate the expression of COX-2. Therefore, the present study demonstrated that enhanced levels of COX-2 expression in patients with coronary atherosclerosis are associated with the downregulation of miR-381 expression, while miR-381 may regulate the occurrence and immune responses of coronary atherosclerosis via COX-2.

Inducible nitric oxide synthase: Good or bad?

Nitric oxide synthases (NOS) are a family of isoforms responsible for the synthesis of the potent dilator nitric oxide (NO). Expression of inducible NOS (iNOS) occurs in conditions of inflammation, and produces large amounts of NO. In pathological conditions iNOS is regarded as a harmful enzyme and is proposed to be a major contributor to diseases of the cardiovascular system such as atherosclerosis. In this review, we address the notion that iNOS is a detrimental enzyme in disease and discuss its potentially beneficial roles. Additionally, we describe other molecules associated with iNOS in diseases such as atherosclerosis, and current research on therapeutic inhibitors tested to reduced pathology associated with cardiovascular diseases (CVD).

High-Fat and Fat-Enriched Diets Impair the Benefits of Moderate Physical Training in the Aorta and the Heart in Rats

AIM

Millions of people die each year due to cardiovascular disease (CVD). A Western lifestyle not only fuses a significant intake of fat with physical inactivity and obesity but also promotes CVD. Recent evidence suggests that dietary fat intake impairs the benefits of physical training. We investigated whether aerobic training could reverse the adverse effects of a high-fat diet (HFD) on the aorta. Then, we explored whether this type of exercise could reverse the damage to the heart that is imposed by fat-enriched diet (FED).

METHODS

Rats were randomly assigned to two experiments, which lasted 8 weeks each. First, rats swam for 60 min and were fed either a regular diet [standard diet (STD)] or an HFD. After aortic samples had been collected, the rats underwent a histopathological analysis for different biomarkers. Another experiment subjected rats that were fed either an STD or an FED to swimming for 20 or 90 min.

RESULTS

The first experiment revealed that rats that were subjected to an HFD-endured increased oxidative damage in the aorta that exercises could not counteract. Together with increased cyclooxygenase 2 expression, an HFD in combination with physical training increased the number of macrophages. A reduction in collagen fibers with an increased number of positive α-actin cells and expression of matrix metalloproteinase-2 occurred concomitantly. Upon analyzing the second experiment, we found that physically training rats that were given an FED for 90 min/day decreased the cardiac adipose tissue density, although it did not protect the heart from fat-induced oxidative damage. Even though the physical training lowered cholesterol levels that were promoted by the FED, the levels were still higher than those in the animals that were given an STD. Feeding rats an FED impaired the swimming protocol's effects on lowering triglyceride concentration. Additionally, exercise was unable to reverse the fat-induced deregulation in hepatic antioxidant and lipid peroxidation activities.

CONCLUSION

Our findings reveal that an increased intake of fat undermines the potential benefits of physical exercise on the heart and the aorta.

Prostanoids in the pathophysiology of human coronary artery

Coronary artery disease is one of the leading causes of death in wordwide. There is growing evidence that prostanoids are involved in the physiology and pathophysiology of the human coronary artery by controlling vascular tone, remodelling of the vascular wall or angiogenesis. In this review, the production of prostanoids and the expression of prostanoid receptors in human coronary artery in health or disease are described. In addition, the interactions between sex hormones and prostanoids, their participations in the development of coronary artery diseases have been addressed. Globally, most of the studies performed in human coronary artery preparations have shown that prostacyclin (PGI₂) has beneficial effects by inducing vasodilatation and promoting angiogenesis while reverse effects are confirmed by thromboxane A₂ (TxA₂). More studies are needed to determine the roles of the other prostanoids (PGE₂, PGD₂ and PGF_2α) in vascular functions of the human coronary artery. Finally, in addition to the in vitro data about the human coronary artery, myocardial infarction induced by cyclooxygenase-2 (COX-2) inhibitor and the protective effects of aspirin after coronary artery bypass surgery suggest that prostanoids are key mediators in coronary homeostasis.

New insights to the mechanisms underlying atherosclerosis in rheumatoid arthritis

Rheumatoid arthritis (RA) is an inflammatory circumstance, which has been associated with increased risk of cardiovascular disease (CVD). Although RA management has been promoted, mortality rate due to CVD remains remarkable. Approximately, 50% of premature death cases in RA are attributable to CVD. RA patients develop atherosclerosis in a greater amount than the general population. Moreover, atherosclerotic lesions develop rapidly in RA patients and might be more susceptible to rupture. The inflammatory condition of RA, such as cytokines, abnormally activated immune cells, play a role in the initiation, perpetuation and exacerbation of atherosclerosis. RA and CVD have genetic and environmental contributing risk factors in common, implying to potential coincidence of both disorders. Accelerated atherosclerosis in RA is attributed to inflammation, which carries its role out both through modulation of traditional risk factors and direct effect on the vessel wall. Hence, anti-inflammatory medications in RA like tumor necrosis factor blockers might have a beneficial effect on preventing cardiovascular development. Increasing age, smoking, hypertension, male gender, hypercholesterolemia and diabetes are enumerated as traditional CVD risk factors. Hopefully, further understanding of the cardiovascular risk factors by perceiving the disease conditions behind CVD, will improve management of cardiovascular risks in patients with RA.

A Variant in COX-2 Gene Is Associated with Left Main Coronary Artery Disease and Clinical Outcomes of Coronary Artery Bypass Grafting

As a particular severe phenotype of coronary artery disease (CAD), left main coronary artery disease (LMCAD) is heritable. Genetic variants related to prostaglandin metabolism are associated with LMCAD. Cyclooxygenase-2 (COX-2), a key synthase in prostaglandin pathways, displays high density in atherosclerotic lesions and promotes early atherosclerosis in CAD progression. We hypothesized that genetic variants in COX-2 gene contribute to LMCAD phenotype susceptibility compared to more peripheral coronary artery disease (MPCAD). In this study, we genotyped COX-2 rs5275, rs5277, and rs689466 of 1544 CAD patients undergoing coronary artery bypass grafting (CABG) and found that rs5277 C allele carriage was associated with LMCAD (adjusted OR: 1.590; 95% CI: 1.103~2.291; p = 0.013). Furtherly, long-term follow-up data suggested that rs5277 C allele carriage increased risk of major adverse cardiac and cerebrovascular events (MACCE) in the whole cohort (adjusted HR: 1.561; 95% CI: 1.025~2.377; p = 0.038) and LMCAD subgroup (adjusted HR: 2.014; 95% CI: 1.036~3.913; p = 0.039) but not in MPCAD subgroup (adjusted HR: 1.375; 95% CI: 0.791~2.392; p = 0.259). In conclusion, we demonstrate that COX-2 rs5277 C allele increases the risk of left main coronary artery lesion and is also correlated with poor prognosis of LMCAD patients with CABG therapy.

Relationship Between Cyclooxygenase-2 Inhibition and Thrombogenesis

Recently there has been considerable interest in the role of cyclooxygenase-2 (COX-2) in thrombosis and myocardial infarction. A large number of clinical and basic studies have focused on whether COX-2 inhibitors can induce a prothrombotic disorder and increase the risk of cardiovascular thrombosis. This article reviews (1) the roles of COX-2 in the metabolism of prostaglandins; (2) the influence of COX-2 inhibition in the platelet aggregation and the antithrombotic function of vascular endothelium; (3) the roles of COX-2 inhibition in atherothrombosis; and (4) clinical trials that examine COX-2 inhibition in relationship to the risk of myocardial infarction. Based on the published data, this review suggests that COX-2 plays varying and sometimes conflicting roles in thrombogenesis, in prostaglandins' metabolism of endothelium in healthy or dysfunctional conditions, and in atherothrombosis. Future investigations under different pathologic conditions are needed to fully understand the net effect of COX-2 inhibition on thrombogenesis. The roles of COX-2 in the pathophysiologic process of cardiovascular thrombosis are diverse and controversial, and need to be further studied to guide clinical practice.

Possible role of antioxidants and nitric oxide inhibitors against carbon monoxide poisoning: Having a clear conscience because of their potential benefits

Carbon monoxide poisoning is one of the important emergency situations manifested by primarily acute and chronic anoxic central nervous system (CNS) injuries and other organ damages. Current descriptions and therapeutic approaches have been focused on the anoxic pathophysiology. However, this point of view incompletely explains some of the outcomes and needs to be investigated extensively. Considering this, we propose that reactive oxygen species (ROS) including especially nitric oxide (NO) are likely to be a key concept to understand the emergency related to CO poisoning and to discover new therapeutic modalities in CO toxicity. If we consider the hypothesis that ROS is involved greatly in acute and chronic toxic effects of CO on CNS and some other vital organs such as heart, it follows that the antioxidant and anti-NO therapies might give the clinicians more opportunities to prevent deep CNS injury. In support of this, we review the subject in essence and summarize clinical and experimental studies that support a key role of ROS in the explanation of pathophysiology of CO toxicity as well as new treatment modalities after CO poisoning.

Cellular and molecular biology of aging endothelial cells

Cardiovascular disease (CVD) is the leading cause of death in the United States and aging is a major risk factor for CVD development. One of the major age-related arterial phenotypes thought to be responsible for the development of CVD in older adults is endothelial dysfunction. Endothelial function is modulated by traditional CVD risk factors in young adults, but advancing age is independently associated with the development of vascular endothelial dysfunction. This endothelial dysfunction results from a reduction in nitric oxide bioavailability downstream of endothelial oxidative stress and inflammation that can be further modulated by traditional CVD risk factors in older adults. Greater endothelial oxidative stress with aging is a result of augmented production from the intracellular enzymes NADPH oxidase and uncoupled eNOS, as well as from mitochondrial respiration in the absence of appropriate increases in antioxidant defenses as regulated by relevant transcription factors, such as FOXO. Interestingly, it appears that NFkB, a critical inflammatory transcription factor, is sensitive to this age-related endothelial redox change and its activation induces transcription of pro-inflammatory cytokines that can further suppress endothelial function, thus creating a vicious feed-forward cycle. This review will discuss the two macro-mechanistic processes, oxidative stress and inflammation, that contribute to endothelial dysfunction with advancing age as well as the cellular and molecular events that lead to the vicious cycle of inflammation and oxidative stress in the aged endothelium. Other potential mediators of this pro-inflammatory endothelial phenotype are increases in immune or senescent cells in the vasculature. Of note, genomic instability, telomere dysfunction or DNA damage has been shown to trigger cell senescence via the p53/p21 pathway and result in increased inflammatory signaling in arteries from older adults. This review will discuss the current state of knowledge regarding the emerging concepts of senescence and genomic instability as mechanisms underlying oxidative stress and inflammation in the aged endothelium. Lastly, energy sensitive/stress resistance pathways (SIRT-1, AMPK, mTOR) are altered in endothelial cells and/or arteries with aging and these pathways may modulate endothelial function via key oxidative stress and inflammation-related transcription factors. This review will also discuss what is known about the role of "energy sensing" longevity pathways in modulating endothelial function with advancing age. With the growing population of older adults, elucidating the cellular and molecular mechanisms of endothelial dysfunction with age is critical to establishing appropriate and measured strategies to utilize pharmacological and lifestyle interventions aimed at alleviating CVD risk. This article is part of a Special Issue entitled "SI: CV Aging".

Vitamin D and atherosclerosis

PURPOSE OF REVIEW

To provide an overview of the association between vitamin D deficiency and atherosclerosis.

RECENT FINDINGS

Vitamin D exerts protective effects on atherosclerosis through multiple mechanisms. It has been shown to protect against endothelial dysfunction, vascular smooth muscle cell proliferation and migration, and modulation of the immune system, as well as the inflammatory response. In addition, vitamin D has been shown to have systemic effects on insulin resistance, dyslipidemia, and hypertension.

SUMMARY

Vitamin D deficiency is widely prevalent in the United States and worldwide. Although deficiency of this fat-soluble vitamin is usually associated with musculoskeletal disorder, it is associated with a wide range of disease processes that include multiple organ systems. Recently, there has been mounting evidence linking vitamin D deficiency to cardiovascular disease and atherosclerosis.

Protective actions of melatonin and growth hormone on the aged cardiovascular system

Epidemiological studies indicate that certain aspects of lifestyle and genetics act as risk factors for a variety of cardiovascular disorders, including coronary disease, hypertension, heart failure and stroke. Aging, however, appears to be the major contributor for morbidity and mortality of the impaired cardiovascular system. Growth hormone (GH) and melatonin seem to prevent cardiac aging, as they contribute to the recovery of several physiological parameters affected by age. These hormones exhibit antioxidant properties and decrease oxidative stress and apoptosis. This paper summarizes a set of studies related to the potential role that therapy with GH and melatonin may play in the protection of the altered cardiac function due to aging, with a focus on experiments performed in our laboratory using the senescence-accelerated mouse as an aging model. In general, we observed significantly increased inflammation, oxidative stress and apoptosis markers in hearts from senescence-accelerated prone 10-month-old animals compared to 2-month-old controls, while anti-inflammatory and antiapoptotic markers as well as endothelial nitric oxide synthase were decreased. Senescence-accelerated resistant animals showed no significant changes with age. GH or melatonin treatment prevented the age-dependent cardiac alterations observed in the senescence-accelerated prone group. Combined administration of GH plus melatonin reduced the age-related changes in senescence-accelerated prone hearts in an additive fashion that was different to that displayed when administered alone. GH and melatonin may be potential agents for counteracting oxidative stress, apoptosis and inflammation in the aging heart.

Dihydroaustrasulfone Alcohol (WA-25) Impedes Macrophage Foam Cell Formation by Regulating the Transforming Growth Factor-β1 Pathway

Atherosclerosis is considered an inflammatory disease. However, clinically used anti-atherosclerotic drugs, such as simvastatin, have many side effects. Recently, several unique marine compounds have been isolated that possess a variety of bioactivities. In a previous study, we found a synthetic precursor of the marine compound (austrasulfone), which is dihydroaustrasulfone alcohol (WA-25), has anti-atherosclerotic effects in vivo. However, the detailed mechanisms remain unclear. Therefore, to clarify the mechanisms through which WA-25 exerts anti-atherosclerotic activity, we used RAW 264.7 macrophages as an in vitro model to evaluate the effects of WA-25. In lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, WA-25 significantly inhibited expression of the pro-inflammatory proteins, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In contrast, simvastatin increased the COX-2 expression compared to WA-25. In addition, WA-25 impedes foam cell formation and up-regulated the lysosomal and cyclic adenosine monophosphate (cAMP) signaling pathway. We also observed that transforming growth factor β1 (TGF-β1) was up-regulated by WA-25 and simvastatin in LPS-induced RAW 264.7 cells, and the promising anti-atherosclerosis effects of WA-25 were disrupted by blockade of TGF-β1 signaling. Besides, WA-25 might act through increasing lipolysis than through alteration of lipid export. Taken together, these data demonstrate that WA-25 may have potential as an anti-atherosclerotic drug with anti-inflammatory effects.

Proliferation of macrophages due to the inhibition of inducible nitric oxide synthesis by oxidized low-density lipoproteins

Oxidized low-density lipoprotein (ox-LDL) is assumed to be a major causal agent in hypercholesteraemia-induced atherosclerosis. Because the proliferation of lipid-loaden macrophages within atherosclerotic lesions has been described, we investigated the dependence of macrophage proliferation on the inhibition of inducible nitric oxide synthase (iNOS) by hypochlorite oxidized LDL. Ox-LDL induces a dose dependent inhibition of inducible nitric oxide synthesis in lipopolysaccharide-interferon stimulated mouse macrophages (J774.A1) with concomitant macrophage proliferation as assayed by cell counting, tritiated-thymidine incorporation and measurement of cell protein. Native LDL did not influence macrophage proliferation and inducible nitric oxide synthesis. iNOS protein and mRNA was reduced by HOCl-oxidized LDL (0-40 µg/ml) as revealed by immunoblotting and competitive semiquantitative PCR. Macrophage proliferation was increased by the addition of the iNOS inhibitor L-NAME. The addition of ox-LDL to L-NAME containing incubations induced no further statistically significant increase in cell number. Nitric oxide donors decreased ox-LDL induced macrophage proliferation and nitric oxide scavengers restored macrophage proliferation to the initial values achieved by ox-LDL. The decrease of cytosolic DNA fragments in stimulated macrophages incubated with ox-LDL demonstrates that the proliferative actions of ox-LDL are associated with a decrease of NO-induced apoptosis. Our data show that inhibition of iNOS dependent nitric oxide production caused by hypochlorite oxidized LDL enhances macrophage proliferation. This might be a key event in the pathogenesis of atherosclerotic lesions.

Terminalia chebula Fructus Inhibits Migration and Proliferation of Vascular Smooth Muscle Cells and Production of Inflammatory Mediators in RAW 264.7

Pathogenesis of atherosclerosis and neointima formation after angioplasty involves vascular smooth muscle cells (VSMCs) migration and proliferation followed by inflammatory responses mediated by recruited macrophages in the neointima. Terminalia chebula is widely used traditional medicine in Asia for its beneficial effects against cancer, diabetes, and bacterial infection. The study was designed to determine whether Terminalia chebula fructus water extract (TFW) suppresses VSMC migration and proliferation and inflammatory mediators production in macrophage (RAW 264.7). Our results showed that TFW possessed strong antioxidative effects in 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging and lipid peroxidation assays. In addition, TFW reduced nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) expression in RAW 264.7 cells. Also, TFW inhibited platelet-derived growth factor (PDGF-BB) induced VSMC migration as determined by wound healing and Boyden chamber assays. The antimigratory effect of TFW was due to its inhibitory effect on metalloproteinase-9 (MMP-9) expression, focal adhesion kinase (FAK) activation, and Rho-family of small GTPases (Cdc42 and RhoA) expression in VSMCs. Furthermore, TFW suppressed PDGF-BB induced VSMC proliferation by downregulation of mitogen activated protein kinases (MAPKs) signaling molecules. These results suggest that TFW could be a beneficial resource in the prevention of atherosclerosis.

Role of farnesoid X receptor in inflammation and resolution

OBJECTIVE

The aim of this paper is to review the developments of farnesoid X receptor (FXR) biology, its ligands, and various functions, in particular we discuss the anti-inflammatory and anti-fibrotic role in chronic inflammatory diseases.

INTRODUCTION

FXR is a ligand-dependent transcription factor belonging to the nuclear hormone receptor superfamily. The accrued data have shown that the FXR plays important roles not only in bile acid, lipid metabolism, and carbohydrate homeostasis, but also in inflammatory responses. The anti-inflammatory and anti-fibrotic effects of FXR on chronic inflammatory diseases are not well documented.

METHODS

A literature survey was performed using PubMed database search to gather complete information regarding FXR and its role in inflammation.

RESULTS AND DISCUSSION

FXR is highly expressed in liver, intestine, kidney and adrenals, but with lower expression in fat tissue, heart and recently it has been found to express in lungs too. Primary bile acids, cholic acid and chenodeoxycholic acid are the natural endogenous ligands for FXR. GW4064 and 6α-ethyl-chenodeoxycholic acid are the synthetic high-affinity agonists. An exhaustive literature survey revealed that FXR acts as a key metabolic regulator and potential drug target for many metabolic syndromes that include chronic inflammatory diseases.

Vascular oxidative stress, nitric oxide and atherosclerosis

In the vascular wall, reactive oxygen species (ROS) are produced by several enzyme systems including NADPH oxidase, xanthine oxidase, uncoupled endothelial nitric oxide synthase (eNOS) and the mitochondrial electron transport chain. On the other hand, the vasculature is protected by antioxidant enzyme systems, including superoxide dismutases, catalase, glutathione peroxidases and paraoxonases, which detoxify ROS. Cardiovascular risk factors such as hypercholesterolemia, hypertension, and diabetes mellitus enhance ROS generation, resulting in oxidative stress. This leads to oxidative modification of lipoproteins and phospholipids, mechanisms that contribute to atherogenesis. In addition, oxidation of tetrahydrobiopterin may cause eNOS uncoupling and thus potentiation of oxidative stress and reduction of eNOS-derived NO, which is a protective principle in the vasculature. This review summarizes the latest advances in the role of ROS-producing enzymes, antioxidative enzymes as well as NO synthases in the initiation and development of atherosclerosis.

Reduced expression of prostacyclin synthase and nitric oxide synthase in subcutaneous arteries of type 2 diabetic patients

Diabetic endothelial dysfunction is characterized by impaired endothelium-dependent relaxation. In this study, we measured the expression of endothelial nitric oxide synthase (eNOS), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), prostacyclin synthase (PGIS), and prostacyclin receptor (IP) in subcutaneous arteries of type-2 diabetic and non-diabetic patients. Subcutaneous arteries were dissected from tissues from seven diabetics (4 males and 3 females) and seven non-diabetics (5 males and 2 females) aged between 18 to 65 years, who underwent lower limb surgical procedures. Diabetics had higher fasting blood glucose compared to non-diabetics, but there were no differences in blood pressure, body mass index and age. Patients were excluded if they had uncontrolled hypertension, previous myocardial infarction, coronary heart disease, renal or hepatic failure and tumor. The relative expression levels of eNOS, COX-1, COX-2, PGIS and IP receptor were determined by Western blotting analysis, normalized with the β-actin level. Increased expression of COX-2 was observed in subcutaneous arteries of diabetics compared to non-diabetics, whereas the expression levels of eNOS and PGIS were significantly lower in diabetics. There were no significant differences in expression levels of COX-1 and IP receptor between the two groups. Immunohistochemical study of subcutaneous arteries showed that the intensities of eNOS and PGIS staining were lower in diabetics, with higher COX-2 staining. In conclusion, type-2 diabetes is associated with higher COX-2 expression, but lower eNOS and PGIS expression in subcutaneous arteries. These alterations may lead to impaired endothelium-dependent vasodilatation, and thus these proteins may be potential targets for protection against the microvascular complications of diabetes.

COX-2 protects against atherosclerosis independently of local vascular prostacyclin: identification of COX-2 associated pathways implicate Rgl1 and lymphocyte networks

Cyxlo-oxygenase (COX)-2 inhibitors, including traditional nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with increased cardiovascular side effects, including myocardial infarction. We and others have shown that COX-1 and not COX-2 drives vascular prostacyclin in the healthy cardiovascular system, re-opening the question of how COX-2 might regulate cardiovascular health. In diseased, atherosclerotic vessels, the relative contribution of COX-2 to prostacyclin formation is not clear. Here we have used apoE(-/-)/COX-2(-/-) mice to show that, whilst COX-2 profoundly limits atherosclerosis, this protection is independent of local prostacyclin release. These data further illustrate the need to look for new explanations, targets and pathways to define the COX/NSAID/cardiovascular risk axis. Gene expression profiles in tissues from apoE(-/-)/COX-2(-/-) mice showed increased lymphocyte pathways that were validated by showing increased T-lymphocytes in plaques and elevated plasma Th1-type cytokines. In addition, we identified a novel target gene, rgl1, whose expression was strongly reduced by COX-2 deletion across all examined tissues. This study is the first to demonstrate that COX-2 protects vessels against atherosclerotic lesions independently of local vascular prostacyclin and uses systems biology approaches to identify new mechanisms relevant to development of next generation NSAIDs.

The role of cyclooxygenase-2 on endurance exercise training in female LDL-receptor knockout ovariectomized mice

Estrogen deprivation in postmenopausal women increases cardiovascular risk. Cardiovascular risk as a result of atherosclerosis is able to induce an inflammatory disease as far as cyclooxygenase-2 ( COX-2) expression. The purpose of the study was to investigate the role of COX-2 on exercise training in female mice low-density lipoprotein receptor knockout ( LDL-KO) with or without ovariectomy. A total of 15 female C57BL/6 mice and 15 female LDL-KO mice were distributed into 6 groups: sedentary control, sedentary control ovariectomized, trained control ovariectomized, LDL-KO sedentary, LDL-KO sedentary ovariectomized and LDL-KO trained ovariectomized. The ascending part of the aorta was stained with H&E and COX-2 expression was assessed by immunohistochemistry. Results revealed that ovariectomy as well as exercise training were not able to induce histopathological changes in mouse aorta for all groups investigated. LDL-KO mice demonstrated plaque containing cholesterol clefts, foamy histiocytes and mild inflammatory process for all groups indistinctly. Ovariectomy induced a strong immunoexpression in atherosclerosis lesion of LDL-KO mice. Nevertheless, a down-regulation of COX-2 expression was detected in LDL-KO trained ovariectomized when compared to LDL-KO sedentary. Our results are consistent with the notion that exercise training is able to modulate COX-2 expression in LDL-KO mice as a result of COX-2 down-regulation.

Cardiovascular effects of selective cyclooxygenase-2 inhibitors

Selective cyclooxygenase-2 inhibitors represent a significant advance in the management of inflammatory disorders. They have similar efficacy to nonselective 'conventional' nonsteroidal anti-inflammatory drugs, but a superior gastrointestinal safety profile. However, a significant caveat is the perceived potential of cyclooxygenase-2 inhibitors to cause adverse cardiovascular effects, an issue first raised by the Vioxx Gastrointestinal Outcomes Research (VIGOR) study of rofecoxib (Vioxx, Merck & Co. Inc.). Mechanisms by which cyclooxygenase-2 inhibitors may increase cardiovascular risk are selective inhibition of prostaglandin I2 over thromboxane A2 within the eicosanoid pathway, which promotes thrombosis, and inhibition of prostaglandins E2 and I2 within the kidney, which leads to sodium and water retention and blood pressure elevation. In spite of this, the cardiovascular findings from VIGOR are not firmly supported by observations from large cohort studies and other clinical trials of selective cyclooxygenase-2 inhibitors, including the Celecoxib Long-term Arthritis Safety Study. The two main theories that explain the VIGOR findings are that the comparator used (naproxen; Naprosyn, Roche) is cardioprotective and that very high doses of rofecoxib were used, but at present neither is backed by firm evidence. Indeed, there is now early evidence that selective cyclooxygenase-2 inhibition with celecoxib may even protect against the progression of cardiovascular disease, on the basis that cyclooxygenase-2 mediates key processes in atherothrombosis. Currently, it is not clear what the net cardiovascular effects of cyclooxygenase-2 inhibitors are. The data are inconsistent and at best, speculative. It may be also that celecoxib and rofecoxib differ in their cardiovascular effects. Clarification of these issues is of vital importance given the vast number of patients presently taking both types of cyclooxygenase-2 inhibitors. Therefore, what is clear in this situation is the urgent need for randomized clinical trials designed specifically to examine the impact of selective cyclooxygenase-2 inhibitors on cardiovascular risk.

Multiple sclerosis: molecular mechanisms and therapeutic opportunities

The pathophysiology of multiple sclerosis (MS) involves several components: redox, inflammatory/autoimmune, vascular, and neurodegenerative. All of them are supported by the intertwined lines of evidence, and none of them should be written off. However, the exact mechanisms of MS initiation, its development, and progression are still elusive, despite the impressive pace by which the data on MS are accumulating. In this review, we will try to integrate the current facts and concepts, focusing on the role of redox changes and various reactive species in MS. Knowing the schedule of initial changes in pathogenic factors and the key turning points, as well as understanding the redox processes involved in MS pathogenesis is the way to enable MS prevention, early treatment, and the development of therapies that target specific pathophysiological components of the heterogeneous mechanisms of MS, which could alleviate the symptoms and hopefully stop MS. Pertinent to this, we will outline (i) redox processes involved in MS initiation; (ii) the role of reactive species in inflammation; (iii) prooxidative changes responsible for neurodegeneration; and (iv) the potential of antioxidative therapy.

Targeting inflammation: impact on atherothrombosis

Atherothrombosis is a worldwide epidemic accounting for an unacceptable toll of deaths and disabilities. Its pathophysiology is complex and hardly referable to a specific mechanism; however, in the last 20 years, a growing amount of evidence has demonstrated that inflammatory processes play a major role from the very beginning to the ultimate complication of atherothrombosis. These evidences are addressing a growing interest toward anti-inflammatory agents as preventive or curative treatments of atherothrombosis. At present, accumulated data are not conclusive, but strong evidence exists in favor of an anti-inflammatory positive effect for several drugs as statins or renin-angiotensin inhibitors. More conclusive data are expected from ongoing trials directly exploring the role of specific cytokines antagonists.

Beneficial effects of the active principle component of Korean cabbage kimchi via increasing nitric oxide production and suppressing inflammation in the aorta of apoE knockout mice

The present study investigated the effects of 3'-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA), the active principle compound of kimchi, on vascular damage in the experimental atherosclerotic animal. HDMPPA was administrated by an intraperitoneal injection of 10 mg/kg per d for 8 weeks to apoE knockout (KO) mice with an atherogenic diet containing 1 % cholesterol, and its effects were compared with vehicle-treated control mice. HDMPPA increased NO content in the aorta, accompanied by a decrease in reactive oxygen species (ROS) concentration. Furthermore, in the HDMPPA-treated group, aortic endothelial NO synthase (eNOS) expression was up-regulated compared with the control group. These results suggested that HDMPPA could maintain NO bioavailability through an increasing eNOS expression and preventing NO degradation by ROS. Furthermore, HDMPPA treatment in apoE KO mice inhibited eNOS uncoupling through an increase in vascular tetrahydrobiopterin content and a decrease in serum asymmetric dimethylarginine levels. Moreover, HDMPPA ameliorates inflammatory-related protein expression in the aorta of apoE KO mice. Therefore, the present study suggests that HDMPPA, the active compound of kimchi, a Korean functional food, may exert its vascular protective effect through the preservation of NO bioavailability and suppression of the inflammatory response.

Role of cyclooxygenase 2 and endothelial nitric oxide synthetase in preclinical atherosclerosis

Cyclooxygenase-2 and endothelial nitric oxide (NO) synthase enzymes may have a role in developing preclinical atherosclerosis. Designed groups were as follows: smoke exposed rats before and during pregnancy, only before pregnancy, and controls. Cross-sectional samples of abdominal aorta were examined immunohistochemically. Cyclooxygenase-2 and eNOS expression was evaluated semi-quantitatively through staining extent (focal, diffuse) and staining intensity. Diffuse COX-2 expression was detected in study groups. Endothelial NO synthase expression was diffuse in study groups. COX-2 and eNOS may contribute to the formation of preatherosclerotic lesions in offspring of rats exposed to cigarette smoke through inflammatory response.

Nitric oxide signaling in vascular biology

Nitric oxide (NO) research has expanded rapidly in the past 20 years, and the role of NO in physiology and pathology has been extensively studied. This review focuses on the pathways of NO synthesis and metabolism in vascular biological systems. Healthy vascular homeostasis is dependent on the integrity of the endothelium, which is a very large dynamic autocrine and paracrine organ with vasodilator, anti-inflammatory, and antithrombotic properties. The importance and relevance of NO signaling is stressed in this review. The potential role of nitrotyrosine formation with vascular pathological conditions is discussed. The use of pharmacologic, biochemical, and molecular biological approaches to characterize, purify, and reconstitute these regulatory pathways should lead to the development of new therapies for various pathological conditions that are characterized by an insufficient production of NO. With more than 77,000 publications in the field of NO signaling, this brief review can only focus on some aspects of the field as it applies to vascular biology. Many molecular targets have been identified for drug development dealing with NO and cyclic guanosine monophosphate formation, metabolism, and function. Many agents have been identified that are in pre-clinical evaluation or in clinical trials. Certainly, many should prove to be important therapeutic additions during the next decade.