Polymorphism in the chemokine receptor 7 gene (CCR7) is associated with previous myocardial infarction in patients undergoing elective coronary angiography.

Coronary artery disease (CAD) remains a major cause of death in developed countries. Both environmental and, less known, genetic factors contribute to progression of CAD to myocardial infarction (MI). Immune system is activated in patients with CAD through dendritic cells (DCs), which present plaque antigens to T lymphocytes. Production of proinflammatory cytokines by activated T cells contributes to plaque rupture in MI. Chemokine receptor 7 (CCR7) on DCs is required for their chemotaxis from plaque to lymph nodes. This makes possible an interaction of DCs with T lymphocytes and initiation of specific immune response. We hypothesized that single nucleotide polymorphisms (SNPs) in CCR7 gene locus are associated with previous MI in patients with CAD. To test this hypothesis, we genotyped six SNPs from the CCR7 gene locus in 300 consecutive patients, admitted for elective coronary angiography. We performed univariate-, multivariate- (including potential confounders) and haplotype-based tests of association of SNPs with previous MI and results of angiography. Allele A of rs17708087 SNP was associated with previous MI. This association remained significant after adjustment for age, sex, smoking, hypercholesterolaemia and drugs used by patients (odds ratio 2.13, 95% confidence interval: 1.13-3.86). Therefore, we conclude that CCR7 gene locus harbours a polymorphism that modifies risk of MI in patients with CAD. Replication of this association could be sought in a prospective cohort of initially healthy individuals.

Angiotensin 1-7 formation in breast tissue is attenuated in breast cancer - a study on the metabolism of angiotensinogen in breast cancer cell lines.

The tissue renin-angiotensin system (RAS) plays an important role in the development and progression of many diseases. It has been confirmed that angiotensin II (ANG II) participates in the proliferation and angiogenesis of breast cancer. Moreover, some RAS dysregulations in cancer have been observed. Recent studies on the role of two opposite axes of angiotensinogen metabolism - ACE (angiotensin-converting enzyme)/ANGII/AT1R (angiotensin receptor type 1) and ACE-2/ANG 1-7/MAS (mitochondrial assembly) - indicate their importance in tumor growth and invasion, but studies describing the metabolic pathways in breast cancer and the role of newer angiotensins, such as ANG 1-12, remain lacking. In this study, the metabolism of angiotensinogen fragments in three breast cancer lines, namely, MDA-MB-231, MCF-7, and T-47D, compared with normal breast tissue cells (PCS-600) was estimated. Incubation of the cancer cells with angiotensinogen resulted in the prevalent formation of ANG 1-7. A difference in the ability to form ANG II was observed between cell lines. In normal breast cells, the strong predominance of the ACE-2/ANG 1-7/MAS pathway was detected. In cancer cells, differences in angiotensinogen metabolism depending on cancer line were observed; the prevalence of the ACE/ANG II/AT1R pathway was shown. Expressions of the RAS component were dysregulated in cancer cells and differed between cell lines. In conclusion, the ability of breast cancer cells to produce numerous angiotensin peptide metabolites was demonstrated. The metabolism of angiotensinogen differed between various types of breast cancer cells. The obtained results indicate the greater importance of the classical pathway - ACE/ANG II/AT1R - in breast cancer cells. The production of ANG 1-12 seems to be marginal in breast tissue, but a tendency for the higher formation of this peptide in cancer cells was observed. The production of ANG 1-7 was significantly lower in cancer cells, whereas the expression of MAS receptor was higher than that in the control. This finding suggests that substances with MAS receptor agonist activity could be useful in the treatment of breast cancer, but this requires further investigations.

BAY x 1005 attenuates atherosclerosis in apoE/LDLR - double knockout mice.

Recently, we have shown that MK-886 - an inhibitor of five lipoxygenase activating protein (FLAP) inhibits atherosclerosis in apolipoprotein E / LDL receptor - double knockout mice. We, therefore, wanted to find out if other FLAP inhibitor - BAYx1005 given at a dose of 1.88 mg per 100 mg of body weight per day during 16 weeks, could also attenuate atherogenesis. In apoE/LDLR - DKO mouse model BAYx1005 inhibited atherogenesis, measured both by "en face" method (23.84 +/- 2.7% vs. 15.16 +/- 1.4%) and "cross-section" method (497236 +/- 31516 microm(2) vs. 278107 +/- 21824 microm(2)). This is the first report that shows the effect of BAYx1005 on atherogenesis in gene-targeted mice.

Anti-atherosclerotic effect of the angiotensin 1-7 mimetic AVE0991 is mediated by inhibition of perivascular and plaque inflammation in early atherosclerosis.

BACKGROUND AND PURPOSE: Inflammation plays a key role in atherosclerosis. The protective role of angiotensin 1-7 (Ang-(1-7)) in vascular pathologies suggested the therapeutic use of low MW, non-peptide Ang-(1-7) mimetics, such as AVE0991. The mechanisms underlying the vaso-protective effects of AVE0991, a Mas receptor agonist, remain to be explored. EXPERIMENTAL APPROACH: We investigated the effects of AVE0991 on the spontaneous atherosclerosis in apolipoprotein E (ApoE)-/- mice, in the context of vascular inflammation and plaque stability. KEY RESULTS: AVE0991 has significant anti-atherosclerotic properties in ApoE-/- mice and increases plaque stability, by reducing plaque macrophage content, without effects on collagen. Using the descending aorta of chow-fed ApoE-/- mice, before significant atherosclerotic plaque develops, we gained insight to early events in atherosclerosis. Interestingly, perivascular adipose tissue (PVAT) and adventitial infiltration with macrophages and T-cells precedes atherosclerotic plaque or the impairment of endothelium-dependent NO bioavailability (a measure of endothelial function). AVE0991 inhibited perivascular inflammation, by reducing chemokine expression in PVAT and through direct actions on monocytes/macrophages inhibiting their activation, characterized by production of IL-1ß, TNF-α, CCL2 and CXCL10, and differentiation to M1 phenotype. Pretreatment with AVE0991 inhibited migration of THP-1 monocytes towards supernatants of activated adipocytes (SW872). Mas receptors were expressed in PVAT and in THP-1 cells in vitro, and the anti-inflammatory effects of AVE0991 were partly Mas dependent. CONCLUSIONS AND IMPLICATIONS: The selective Mas receptor agonist AVE0991 exhibited anti-atherosclerotic and anti-inflammatory actions, affecting monocyte/macrophage differentiation and recruitment to the perivascular space during early stages of atherosclerosis in ApoE-/- mice. LINKED ARTICLES: This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Inhibition of NOS-2 induction in LPS-stimulated J774.2 cells by 1, 5-isoquinolinediol, an inhibitor of PARP.

Activation of both poly (ADP-ribose) polymerase (PARP) and inducible nitric oxide synthase (NOS-2) have been implicated in the pathogenesis of various forms of inflammation, therefore compounds which may simultaneously inhibit both pathways are of potential therapeutic interest. We tested the influence of potent inhibitor of PARP, 1, 5-isoquinolinediol (ISO), on NOS-2 induction in model of mouse macrophages (cell line J774.2) stimulated with lipopolysaccharide (1 microg/ml). Pretreatment with ISO (1-300 microM) resulted in dose-dependent inhibition of accumulation of NOS-2-derived nitrite in culture medium (IC(50) = 9,3 microM) as well as inhibition of NOS-2 protein induction in cultured J774.2 cells; ISO given 10 hours after LPS did not influence activity of NOS-2. Interestingly, another PARP inhibitor, 3-aminobenzamide (3-AB, 10-3000 microM), did not influence 24-hr nitrite accumulation in J774.2 cell culture, either administered 15 minutes prior to LPS or 10 hrs after LPS. Scavenging of reactive oxygen species by use of mixture of SOD and catalase (SOD/Cat, 100/300 - 1000/3000 U/ml) as well as cell permeable SOD-mimetic [Mn(III)TBAP, 1- 100 microM], did not influence NOS-2 induction in J774.2 cells. In summary, we identified 1, 5-isoquinoline as potent inhibitor of induction of NOS-2 in LPS-treated mouse macrophages. The exact mechanism of inhibitory action of this compound on NOS-2 induction requires further investigation.

Perindoprilat changes ANG (1-9) production in renal arteries isolated from young spontaneously hypertensive rats after ANG I incubation.

We used mass spectrometry to quantitate production of angiotensinogen metabolites in renal artery of 3- and 7-month-old Wistar-Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR). Tissue fragments were incubated for 15 min in oxygenated buffer, with added angiotensin I. Concentrations of angiotensins I (ANG I), II (ANG II), III (ANG III), IV (ANG IV), angiotensin (1-9) [ANG (1-9)], angiotensin (1-7) [ANG (1-7)], and angiotensin (1-5) [ANG (1-5)], excreted into the buffer during experiment, were measured using liquid chromatography-mass spectrometry (LC/MS) and expressed per mg of dry tissue. Effects of pretreatment with 10 microM perindoprilat on the production of ANG I metabolites were quantitated. Background production of any of ANG I metabolites differed neither between WKY and SHR rats nor between 3- and 7-month-old rats. Perindoprilat pretreatment of renal arteries resulted, as expected, in decrease of ANG II production. However, renal arteries of 7-month-old SHR rats were resistant to ACE inhibitor and did not change ANG II production in response to perindoprilat. In renal arteries, taken from 3-month-old rats, pretreated with perindoprilat, incubation with ANG I, resulted in the level of ANG (1-9) significantly higher in SHR than WKY rats. Our conclusion is that in SHR rats, sensitivity of renal artery ACE to perindoprilat inhibition changes with age.

New cationically modified pullulan attenuates atherogenesis and influences lipid metabolism in apoE-knockout mice.

Pullulan is a biocompatible polysaccharide obtained from black, yeast-like fungus Aureobasidium pullulans. This polymer is used to deliver various substances to the liver because of its specificity for this organ. Pullulan is internalized into hepatocytes in the process of asialoglycoprotein receptor mediated endocytosis. Recently, by reaction with glycidyltrimethylammonium chloride (GTMAC) we have successfully synthesized a cationically-modified pullulan (Pull-GTMAC). Pull-GTMAC exhibits some unique beneficial effects not found for its native counterpart. In this article we have reported for the first time that Pull-GTMAC administered orally to apoE-knockout mice (murine model of atherosclerosis) at a dose of 300 mg/kg b.w./day for 18 weeks showed anti-atherosclerotic activity reducing the area of atherosclerotic plaque. We have also found that Pull-GTMAC at a dose of 300 mg/kg b.w./day increases both the average daily mass of feces and the average number of droppings excreted by apoE(-/-) mouse in relation to the control sample derived from the mice fed with feed without the tested compound. However, the raw fat content in the feces of apoE-knockout mice was decreased in the group fed with the diet containing Pull-GTMAC towards control group of animals. Pull-GTMAC caused also statistically significant increase of mRNA level for LDL receptor in the apoE(-/-) mice liver after administration at a dose of 300 mg/kg/b.w./day for 18 weeks. However, the compound had no impact on lipid profile in serum of the tested mice. What is more, the studies on HepG2 cell line indicated an antiproliferative potential of cationically modified pullulan after 24 hour and 48 hour of incubation with the polysaccharide. In this paper we have shown for first time that cationically modified pullulan has antiatherogenic potential and influences on lipid metabolism.

Exogenous Angiotensin I Metabolism in Aorta Isolated from Streptozotocin Treated Diabetic Rats.

Purpose. Products of angiotensin (ANG) I metabolism may predispose to vascular complications of diabetes mellitus. Methods. Diabetes was induced with streptozotocin (75 mg/kg i.p.). Rat aorta fragments, isolated 4 weeks later, were pretreated with perindoprilat (3 µM), thiorphan (3 µM), or vehicle and incubated for 15 minutes with ANG I (1 µM). Products of ANG I metabolism through classical (ANG II, ANG III, and ANG IV) and alternative (ANG (1-9), ANG (1-7), and ANG (1-5)) pathways were measured in the buffer, using liquid chromatography-mass spectrometry. Results. Incubation with ANG I resulted in higher concentration of ANG II (P = 0.02, vehicle pretreatment) and lower of ANG (1-9) (P = 0.048, perindoprilat pretreatment) in diabetes. Preference for the classical pathway is suggested by higher ANG III/ANG (1-7) ratios in vehicle (P = 0.03), perindoprilat (P = 0.02), and thiorphan pretreated (P = 0.02) diabetic rat. Within the classical pathway, ratios of ANG IV/ANG II (P = 0.01) and of ANG IV/ANG III (P = 0.049), but not of ANG III/ANG II are lower in diabetes. Conclusions. Diabetes in rats led to preference toward deleterious (ANG II, ANG III) over protective (ANG IV, ANG (1-9), and ANG (1-7)) ANG I metabolites.

Urinary cysteinyl leukotrienes in one-year follow-up of percutaneous transluminal angioplasty for peripheral arterial occlusive disease.

BACKGROUND AND AIMS: Treatment of severe peripheral arterial occlusive disease requires percutaneous revascularization. However, little is known about risk factors or predictors for reocclusion/restenosis. Cysteinyl leukotrienes are highly bioactive lipid mediators of inflammation. Their intravascular production may take place in the atheromatous plaque or result from interaction within activated leukocyte-platelet aggregates. METHODS: We prospectively measured urinary leukotriene E4, the main end-metabolite of cysteinyl leukotrienes in a group of 179 subjects with peripheral artery occlusive disease of the lower extremities. At the enrollment to the study, 22.9% had angioplasty and the remaining had angioplasty with stent implantation. During 12-month follow-up, 29.6% developed reocclusion/restenosis despite a standard pharmacotherapy. We evaluated treatment outcomes at 1, 3, 6 and 12-month follow-up visits, along with urinary leukotriene E4 excretion. RESULTS: During the study period, we observed a linear increase of urinary leukotriene E4 excretion only in subjects whose lower limb ischemia worsened. Moreover, elevated leukotriene E4 in urine was found only in subjects who developed reocclusion/restenosis. This was significant not only as a coincidence at the time of the follow-up visit, but leukotriene E4 elevation preceded clinical manifestation of reocclusion/restenosis. CONCLUSIONS: Our results demonstrated that serial measurements of urinary leukotriene E4 allowed to predict failure of angioplasty with/or without stent implantation for peripheral artery occlusive disease. However, to prove causality between cysteinyl leukotrienes overproduction and occlusive lower limb ischemia, a clinical trial with leukotrienes modifying drugs would be required.

11-dehydro thromboxane B2 levels after percutaneous transluminal angioplasty in patients with peripheral arterial occlusive disease during a one year follow-up period.

The aim of our study was to determine if the generation of thromboxane is altered in patients with peripheral arterial occlusive disease following percutaneous transluminal angioplasty (PTA) during a one year follow-up period. In this study, 175 patients diagnosed with peripheral arterial occlusive disease (PAOD) and demonstrating short-distance claudication or ischemic rest pain, requiring PTA in either the iliac, femoral, or popliteal arteries, were enrolled. The excretion of 11-dehydro thromboxane B2 (TXB2) was measured in urine samples by high-performance liquid chromatography-mass spectrometry and recalculated based on the creatinine concentration. The urine samples were collected the morning prior to PTA, immediately following PTA and the day after PTA. All of the study subjects were then observed for a period of 12 months. Urine samples were also collected during the follow-up visits, and the levels of 11-dehydro TXB2 were measured at 1 month (1458.1 pg/mg creatinine ± 1240.8), 3 months (1623.3 pg/mg creatinine ± 1362.2), 6 months (1314.8 pg/mg creatinine ± 1378.7) and 12 months (1473.2 pg/mg creatinine ± 1455.2) after the PTA procedure. All of the patients were taking 75 mg of aspirin per day throughout the course of the study, as well as 75 mg of clopidogrel for six weeks following PTA. Overall, the mean TXB2 values immediately after PTA were significantly higher than either before the procedure (1524.4 pg/mg creatinine ± 1411.1 vs. 2098.1 pg/mg creatinine ± 1661.8; P = 0.00002), the day after PTA, or at any other point during the study. Moreover, preoperative TXB2 levels correlated well with the composite endpoints of death, myocardial infarction and stroke during the follow-up period (OR 7.42 [CI 95% = 1.2-48.8]; P = 0.02). Our findings suggest that clinicians should consider the use of TXA2 synthase inhibitors and receptor antagonists in combination with peripheral percutaneous transluminal angioplasty in patients with peripheral arterial occlusive disease.

Endothelial action of thienopyridines and thienopyrimidinones in the isolated guinea pig heart.

Antiplatelet thienopyridines (ticlopidine, clopidogrel) and their thienopyrimidinone congeners, induce prostacyclin-dependent thrombolysis in vivo. Here we tested whether thienopyridines (ticlopidine, clopidogrel, and its enantiomer without antiplatelet properties) and structurally related thienopyrimidinones release NO from coronary endothelium in the isolated guinea pig heart, perfused according to Langendorff technique. The involvement of endothelium-derived NO in coronary vasodilation induced by these agents was assessed by effect of L-N(G)-nitro-arginine methyl ester (L-NAME). In addition, effect of thienopyridines or thienopyrimidinones on nitrite accumulation in cultured endothelium was assayed. Tienopyridines (10-100 micromol L(-1)) and thienopyrimidinones (10-30 micromol L(-1)) produced concentration-dependent increase in coronary flow comparable to that induced by acetylcholine (0.1 micromol L(-1)) or bradykinin (3 nmol L(-1)) which was inhibited by L-NAME (by 50-70%) but not by indomethacin. Furthermore, thienopyridines and thienopyrimidinones caused NO release from cultured endothelial cells. In conclusion, both thienopyridines independently from their antiplatelet action and their thienopyrimidinone congeners that are devoid of antiplatelet action stimulate coronary endothelium to release NO. Endothelial action of these compounds merits further investigation.

The involvement of adhesion molecules and lipid mediators in the adhesion of human platelets to eosinophils.

Platelet-leukocyte interactions represent an important determinant of the inflammatory response. Although mechanisms of platelet-neutrophil adhesion were studied extensively, little is known on the mechanisms of platelet-eosinophil interactions. The aim of the present study was to analyze the involvement of adhesion molecules and lipid mediators in platelet-eosinophil adhesion as compared to platelet-neutrophil adhesion. For that purpose human platelets, eosinophils and neutrophils were isolated and platelet-eosinophil and platelet-neutrophil adhesion induced by thrombin (30 mU/ml), LPS (0.01 microg/ml) and fMLP (1 microM) was quantified using the "rosettes" assay. The involvement of adhesion molecules such as selectin P, glycoprotein IIb/IIIa (GPIIb/IIIa) and lipid mediators such as of thromboxane A2 (TXA2), platelet activating factor (PAF) and cysteinyl leukotrienes (cysLTs) were studied using monoclonal antibodies and pharmacological inhibitors, respectively. Thrombin (30 mU/ml), LPS (0.01 microg/ml) and fMLP (1 microM) each of them induced platelet-eosinophil adhesion that was even more pronounced as compared with platelet-neutrophil adhesion induced by the same stimulus. Anti-CD62P antibody (1 microg/ml) and anti-GP IIb/IIIa antibody (abciximab-3 microg/ml) strongly inhibited platelet-eosinophil as well as platelet-neutrophil adhesion. Aspirin inhibited platelet-eosinophil adhesion, while MK 886-a FLAP inhibitor (10 microM), or WEB 2170-a PAF receptor antagonist (100 microM) were less active. On the other hand aspirin, MK 886 and WEB 2170 all three of them inhibited platelet-neutrophil adhesion. In summary, platelets adhered avidly to eosinophils both after activation of platelets by thrombin, eosinophils by fMLP or simultaneous activation of platelets and eosinophils by LPS. Similarly to platelet-neutrophil interaction adhesion of platelets to eosinophils involved not only adhesion molecules (selectin P, GPIIb/IIIa), but also lipid mediators such as TXA2. The involvement of PAF and cysteinyl leukotrienes in platelet-eosinophil adhesion was less pronounced as compared to platelet-neutrophil adhesion.

Effect of curcumin on atherosclerosis in apoE/LDLR-double knockout mice.

It is widely appreciated that inflammation and oxidant stress contribute to atherogenesis. Curcumin, a polyphenolic natural compound has been reported to possess anti-inflammatory and anti-oxidant actions. We hypothesized that curcumin could inhibit the development of atherosclerosis in the apoE/LDLR-double knockout mice fed with Western diet (21% fat, 0.15% cholesterol w/w, without cholic acid). Curcumin (purity>or=98%), premixed with diet, was given for 4 months at a dose of 0.3 mg/ per day/ per mouse. In this model curcumin inhibited atherogenesis, measured both by "en face" method (25,15+/-2,9% vs. 19,2+/-0,6%, p<0,05) and "cross-section" method (565867+/-39764 microm2 vs. 299201+/-20373 microm2, p<0,05). Importantly, curcumin influenced neither the concentrations of cholesterol and triglycerides in blood nor animal body weight. To our knowledge, this is the first report that shows the anti-atherogenic effect of low dose of curcumin in fine model of atherosclerosis: gene-targeted apoE/LDLR-double knockout mice.

Inhibition of nuclear factor-kappaB attenuates artherosclerosis in apoE/LDLR - double knockout mice.

Nuclear factor - kappaB (NF-kappaB) is a good therapeutic target for cardiovascular disease and numerous efforts are being made to develop safe NF-kappaB inhibitors. Nowadays many authors address NF-kappaB as a major therapeutic target in atherosclerosis, especially for preventive measures, in the light of two main hypothesis of atherosclerosis: oxidation and inflammation. We hypothesized that ammonium pyrrolidinedithioocarbamate (PDTC) - a well-known inhibitor of NF-kappaB could inhibit the development of atherosclerosis in this experimental model. We used apoE/LDLR - DKO mouse model, which is considered as a one of the best models to study the anti-atherosclerotic effect of drugs. In this model PDTC inhibited atherogenesis, measured both by "en face" method (25,15+/-2,9% vs. 15,63+/-0,6%) and "cross-section" method (565867+/-39764 microm2 vs. 291695+/-30384 microm2). Moreover, PDTC did not change the profile of cholesterol and triglycerides in blood. To our knowledge, this is the first report that shows the effect of PDTC on atherogenesis in gene-targeted apoE/LDLR - double knockout mice.

Superoxide dismutase activity and expression in human venous and arterial bypass graft vessels.

UNLABELLED: Venous bypass grafts are more prone to accelerated atherosclerosis than arterial grafts, which is partly related to increased oxidative stress and diminished nitric oxide bioavailability. In veins superoxide production is dependent primarily on nox2 NAD(P)H oxidase expression, while in arteries nox4 appears to play an important role. This may in part explain differences in susceptibility to graft failure. Net levels of oxidative stress are however determined in parallel by the production as well as by degradation of free radicals (eg. by superoxide dismutases, catalases, thioredoxins etc). The differences in superoxide dismutase (SOD) expression and activity in human bypass conduit vessels remain unclear. Accordingly, we aimed to compare SOD activity and protein levels as well as its functional effects on superoxide production in segments of human internal mammary arteries (IMA) and saphenous veins (HSV) from patients undergoing bypass graft surgery (n=24). SOD activity was assessed by inhibition of pyrogallol autoxidation, Cu-Zn SOD and Mn SOD protein levels were studied by immunoblotting. Basal superoxide release was detected by lucigenin (5 microM) enhanced chemiluminescence. Total SOD activity did not differ significantly between HSV and IMA. Similarly, no difference was observed in SOD activity in the presence of KCN (Mn-SOD). Human bypass conduit vessels show amounts of Cu-Zn SOD or Mn-SOD protein levels. In both HSV and IMA segments superoxide production was more than doubled in the presence of SOD inhibitor-DETC. CONCLUSIONS: These studies suggest that the differences in oxidative stress between human arteries and veins are unlikely to be caused by SOD activity. However SOD plays and important role in amelioration of oxidative stress in both types of vessels.

Mouse models of experimental atherosclerosis.

Since 1992 the mouse has become an excellent model for experimental atherosclerosis research. Until 1992, the diet -- induced atherosclerosis mouse model has been used effectively, but the lesions tended to be small and were limited to early fatty-streak stage. This model was also criticized because of the toxicity and inflammatory responses due to the diet. In 1992 the first line of gene targeted animal models, namely apolipoprotein E -- knockout mice was developed. Of the genetically engineered models, the apoE -- deficient model is the only one that develops extensive atherosclerotic lesions on a chow diet. It is also the model in which the lesions have been characterized most thoroughly. The lesions develop into fibrous plaques; however, there is no evidence that plaque rupture occurs in this model. The LDL receptor - deficient model has elevated LDL levels, but no lesions, or only very small lesions, form on the chow diet, however, robust lesions do form on the western-type diet. The creation of apoE -- knockout mice has changed the face of atherosclerosis research.

Effect of aspirin on cysteinyl leukotrienes production by eosinophils co-cultured with epithelial cells.

Eosinophils have long been considered to play solely crucial role in the pathogenesis of aspirin-induced asthma, however increasing evidence suggest that the bronchial epithelium is also involved in the initiation and maintenance of allergic inflammation. Epithelial cells and eosinophils retained within airways interact reciprocally to mount and sustain inflammatory response. Recently, we have shown that eosinophil-epithelial cell interactions are capable of amplifying the production of cysteinyl leukotrienes (Cys-LTs). The aim of this study was to investigate if there is any influence of aspirin (ASA) on Cys-LTs and prostaglandin E2 (PGE(2)) production in the model of co-cultured human epithelial cells (line BEAS-2B) and human eosinophils. Synthesis of Cys-LTs in eosinophils was increased after incubation with ASA. At the same time the production of PGE(2) was decreased by aspirin (n=32). BEAS-2B cells barely formed Cys-LTs; addition of ASA increased this production, while production of PGE(2) was inhibited by aspirin (n=32). Synthesis of Cys-LTs by eosinophils co-incubated with BEAS-2B was nearly 7-fold higher than that of activated eosinophils alone (1631.5 pg/ml +/- 154 vs. 258 pg/ml +/- 31; p<0.05; n=32). Surprisingly, in the eosinophil-epithelial cell co-culture, aspirin inhibited both augmentation of Cys-LTs synthesis (from 1631.5 pg/ml +/- 154 to 1458 pg/ml +/- 137; p<0.05; n=32) and the production of PGE2 (from 2640 pg/ml +/- 231 to 319 pg/ml +/- 27; p<0.05; n=32). In summary, we have demonstrated that interactions between non-atopic eosinophils and epithelial cells result in augmentation of Cys-LTs production, and this augmentation could be inhibited by aspirin.

Eosinophil-epithelial cell interaction augments cysteinyl leukotrienes synthesis.

Eosinophils accumulation in the airways and sustained eosinophil-derived cysteinyl leukotrienes production represent key elements of the inflammatory response seen in asthma. However, it is not known whether activated epithelial cells influence cysteinyl leukotrienes production by eosinophils from healthy valunteers. The aim of the present study was therefore to analyse the effects of interactions between non-atopic eosinophils and epithelial cells on cysteinyl leukotrienes production in vitro. We measured cysteinyl leukotrienes released by phorbol 12-myristate 13-acetate (PMA) -activated human eosinophils or epithelial cells (human bronchial epithelial cell line -BEAS-2B) cultured alone or together. While activated BEAS-2B cells barely formed leukotrienes (1.39 pg/ml +/- 0.2) (n=32), activated eosinophils produced considerable amount of them (62.25 pg/ml +/- 10.29) (n=32). Interestingly, when activated eosinophils and epithelial cells were co-incubated, production of cysteinyl leukotrienes increased substantially (571.1 pg/ml +/- 80.9) (n=32). Thus, eosinophil-epithelial cell interactions, when occur, are associated with increased biosythesis of cysteinyl leukotrienes.

Significant deterioration of anti-atherogenic efficacy of nebivolol in a double (apolipoprotein E and endothelial nitric oxide synthase) knockout mouse model of atherosclerosis in comparison to single (apolipoprotein E) knockout model.

Anti-atherogenic action of nebivolol in apolipoprotein E (apoE)-single knockout mouse model can be explained by its beneficial effect on endothelium, especially on endothelial nitric oxide synthase (eNOS). We, therefore, decided to use apoE and eNOS-double knockout mouse model to confirm that mechanism of nebivolol beneficial action. In apoE-single knockout mice, lesion area measured by "cross-section" of aortic roots was 79,244 ± 6,143 µm(2) in the control group versus 65,347 ± 6,152 µm(2) in nebivolol-treated group (P<0.05). However, in apoE and eNOS-double knockout mice, lesion area measured by "cross-section" of aortic roots was 92,319 ± 8,876 µm(2) in the control group versus 98,609 ± 9,164 µm(2) in nebivolol-treated group (P>0.05). The comparison between apoE-single knockout mice and apoE & eNOS-double knockout mice without treatment also showed statistically significant difference: 81,232 ± 8,264 µm(2) versus 92,319 ± 8,876 µm(2) (P<0.05). This is the first report that describes the effect of nebivolol on atherogenesis in apoE and eNOS-double knockout mice, proving directly the necessity of the presence of eNOS in endothelium for nebivolol to show its an anti-atherogenic potency.

Effect of nebivolol treatment on atherosclerotic plaque components in apoE-knockout mice.

Nebivolol, a third generation beta1-blocker was previously found to reduce the size of atherosclerotic lesions. The aim of this study was to assess the effect of orally administered nevibolol on the components of the atherosclerotic plaque in apoE-deficient mice. The quantitative evaluation of cross-sectioned plaques stained by histological and immunohistochemical techniques revealed that treatment with nebivolol (2.0 µol per kg b.w.) for 4 months caused a decrease in the necrotic core area (by 46%, p=0.03), density of CD68+ macrophages (by 41%, p=0.008) and CD3+ lymphocytes (by 16%, p=0.03), collagen content (by 49%, p=0.008) and the activity area of metalloproteinases (by 48%, p=0.008), as well as an increase in the smooth muscle content of the fibromuscular cap (by 46%, p=0.008). These effects suggest that nebivolol suppresses the inflammatory/immune processes in the plaque and enhances its stability.