Acute daily exposure to ambient air pollution impairs endothelium-dependent vasodilator responses in young, healthy individuals.

Exposure to ambient air pollution influences cardiovascular (CV) morbidity and mortality. The differential effects of changing particulate or gaseous air pollution on endothelial function in young healthy individuals remain unclear. The aim of this study was to evaluate the relationships between exposures to different pollutants and vascular function in a group of 39 young (33±11 years old) subjects with low CV risk. Flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) were performed, when air pollution reached highest levels (heating period) and repeated in a subgroup of 18 participants a few months later (just before the heating period starts). Daily mean concentrations of PM2.5 and PM10 were inversely correlated with FMD, and this relationship remained significant after adjusting for factors known to affect vascular dysfunction. Endothelial function did not differ between the two time points studied. However, we observed a strong inverse association between the change in the concentration of particulate matter (deltaPM2.5 and deltaPM10) and the change in FMD (deltaFMD) between the two visits (R= -0.65, p= 0.02; R= -0.64, p= 0.02, respectively). In summary, we provide evidence that the concentration of PM2.5 and PM10, but not SO2, NO, NO2, CO, or O3 is associated with impaired endothelial function in young, healthy individuals.

Is systemic inflammation a missing link between periodontitis and hypertension? Results from two large population-based surveys.

OBJECTIVE: The primary objective was to investigate the relationship between periodontitis and hypertension in two independent large surveys. The secondary objective was to ascertain whether systemic inflammation had a mediation effect in the association. METHODS: This cross-sectional study analysed representative samples of the US (n = 3460; NHANES 2009/10) and Korean (n = 4539; 2015 KNHANES VI-3) populations. The association between periodontitis (exposure), hypertension (outcome) and inflammatory markers [C-reactive protein (CRP) and white blood cell counts (WBC)] (mediators) was assessed using multivariate linear and logistic regression models and mediation analysis. RESULTS: Participants with periodontitis were more likely to have hypertension (NHANES: OR = 1.3, 95% CI: 1.0-1.6, P = 0.025; KNHANES: OR = 1.2, 95% CI: 1.0-1.4, P = 0.041) and actual systolic blood pressure ≥ 140 mmHg (NHANES: OR = 1.6, 95% CI: 1.1-2.3, P < 0.001; KNHANES: OR = 1.3, 95% CI :1.0-1.6, P < 0.031) than those without the disease. These associations were independent of age, gender, BMI, education level, smoking, alcohol consumption, creatinine, physical activity, presence of other comorbidities and confirmed in participants not taking antihypertensive medications. Diagnosis of periodontitis was directly associated with WBC (in both surveys: NHANES: ß ± SE = 0.3 ± 0.1, P < 0.004; KNHANES: ß ± SE = 0.3 ± 0.1, P < 0.001) and with CRP levels (in one survey: NHANES: ß ± SE = 0.1 ± 0.03, P < 0.007; KNHANES: ß ± SE = 0.1 ± 0.04, P > 0.213). Mediation analyses confirmed that CRP acted as a mediator in the association between periodontitis and hypertension in both populations (mediated effect: NHANES: ß ± SE = 0.010 ± 0.003, P < 0.001; KNHANES: ß ± SE = 0.003 ± 0.001, P = 0.015). WBC acted as a mediator in the KNHANES (mediated effect: ß ± SE = 0.004 ± 0.001, P = 0.004) whilst in the NHANES, its effect was dependent of CRP inclusion in the model (mediated effect WBC + CRP: ß ± SE = 0.002 ± 0.001, P = 0.001). CONCLUSIONS: These findings suggest that periodontitis is closely linked to hypertension and systemic inflammation is, in part, a mediator of this association.

Nox1/4 inhibition exacerbates age dependent perivascular inflammation and fibrosis in a model of spontaneous hypertension.

Hypertension is associated with oxidative stress and perivascular inflammation, critical contributors to perivascular fibrosis and accelerated vascular ageing. Oxidative stress can promote vascular inflammation, creating options for potential use of NADPH oxidase inhibitors in pharmacological targeting of perivascular inflammation and its consequences. Accordingly, we characterized age-related changes in oxidative stress and immune cell infiltration in normotensive (WKY) and spontaneously hypertensive rats (SHRs). Subsequently, we used pharmacological inhibitors of Nox1 (ML171) and Nox1/Nox4 (GKT137831; 60 mg/kg), to modulate NADPH oxidase activity at the early stage of spontaneous hypertension and investigated their effects on perivascular inflammation and fibrosis. RESULTS: Ageing was associated with a progressive increase of blood pressure as well as an elevation of the total number of leukocytes, macrophages and NK cells infiltrating perivascular adipose tissue (PVAT) in SHRs but not in WKY. At 1 month of age, when blood pressure was not yet different, only perivascular NK cells were significantly higher in SHR. Spontaneous hypertension was also accompanied by the higher perivascular T cell accumulation, although this increase was age independent. Aortic Nox1 and Nox2 mRNA expression increased with age only in SHR but not in WKY, while age-related increase of Nox4 mRNA in the vessels has been observed in both groups, it was more pronounced in SHRs. At early stage of hypertension (3-months) the most pronounced differences were observed in Nox1 and Nox4. Surprisingly, GKT137831, dual inhibitor of Nox1/4, therapy increased both blood pressure and perivascular macrophage infiltration. Mechanistically, this was linked to increased expression of proinflammatory chemokines expression (CCL2 and CCL5) in PVAT. This inflammatory response translated to increased perivascular fibrosis. This effect was likely Nox4 dependent as the Nox1 inhibitor ML171 did not affect the development of spontaneous hypertension, perivascular macrophage accumulation, chemokine expression nor adventitial collagen deposition. In summary, spontaneous hypertension promotes ageing-associated perivascular inflammation which is exacerbated by Nox4 but not Nox1 pharmacological inhibition.

Significance of sphingosine-1-phosphate in cardiovascular physiology and pathology.

Sphingosine-1-phosphate (S1P) is a signaling lipid, synthetized by sphingosine kinases (SPHK1 and SPHK2), that affects cardiovascular function in various ways. S1P signaling is complex, particularly since its molecular action is reliant on the differential expression of its receptors (S1PR1, S1PR2, S1PR3, S1PR4, S1PR5) within various tissues. Significance of this sphingolipid is manifested early in vertebrate development as certain defects in S1P signaling result in embryonic lethality due to defective vasculo- or cardiogenesis. Similar in the mature organism, S1P orchestrates both physiological and pathological processes occurring in the heart and vasculature of higher eukaryotes. S1P regulates cell fate, vascular tone, endothelial function and integrity as well as lymphocyte trafficking, thus disbalance in its production and signaling has been linked with development of such pathologies as arterial hypertension, atherosclerosis, endothelial dysfunction and aberrant angiogenesis. Number of signaling mechanisms are critical - from endothelial nitric oxide synthase through STAT3, MAPK and Akt pathways to HDL particles involved in redox and inflammatory balance. Moreover, S1P controls both acute cardiac responses (cardiac inotropy and chronotropy), as well as chronic processes (such as apoptosis and hypertrophy), hence numerous studies demonstrate significance of S1P in the pathogenesis of hypertrophic/fibrotic heart disease, myocardial infarction and heart failure. This review presents current knowledge concerning the role of S1P in the cardiovascular system, as well as potential therapeutic approaches to target S1P signaling in cardiovascular diseases.

Oxidative stress and inflammatory markers in prediabetes and diabetes.

Prediabetes is a state of elevated plasma glucose in which the threshold for diabetes has not yet been reached and can predispose to the development of type 2 diabetes and cardiovascular diseases. Insulin resistance and impaired beta-cell function are often already present in prediabetes. Hyperglycemia can upregulate markers of chronic inflammation and contribute to increased reactive oxygen species (ROS) generation, which ultimately cause vascular dysfunction. Conversely, increased oxidative stress and inflammation can lead to insulin resistance and impaired insulin secretion. Proper treatment of hyperglycemia and inhibition of ROS overproduction is crucial for delaying onset of diabetes and for prevention of cardiovascular complications. Thus, it is imperative to determine the mechanisms involved in the progression from prediabetes to diabetes including a clarification of how old and new medications affect oxidative and immune mechanisms of diabetes. In this review, we discuss the relationship between oxidative stress and hyperglycemia along with links between inflammation and prediabetes. Additionally, the effects of hyperglycemic memory, microvesicles, micro-RNA, and epigenetic regulation on inflammation, oxidative state, and glycemic control are highlighted. Adipose tissue and their influence on chronic inflammation are also briefly reviewed. Finally, the role of immune-targeted therapies and anti-diabetic medication on glycemic control and oxidative stress are discussed.

Effects of controlled physical activity on immune cell phenotype in peripheral blood in prehypertension - studies in preclinical model and randomised crossover study.

Hypertension (HT) is a global public health issue. There are many behavioural risk factors including unhealthy diet, tobacco use and alcohol consumption as well physical inactivity that contribute to the development of high blood pressure (BP) and its complications. Favourable effect of regular physical activity on treatment or prevention of hypertension by improvement of endothelial function is widely accepted however little is known about its relationship with immune system. Thus, the aim of this study was to assess the role of moderate regular physical activity on immune cell phenotype. T cell and monocyte subsets were characterised in 31 subjects with prehypertension (130 - 139 mmHg systolic and 85 - 89 mmHg diastolic blood pressure) who participated in moderate training (3 times/week) on cyclometers for 3 months in crossover study design. Complementary study was performed in murine model of Ang II-induced hypertension and ten-week-old animals were trained on a treadmill (5 times/week, 1 hour) for 2 weeks before and 1.5 weeks after minipumps implantation. In the context of elevated blood pressure regular physical activity had modest influence on immune cell phenotype. Both in human study and murine model we did not observe effects of applied exercise that can explain the mechanism of BP reduction after short-term regular training. Twelve-weeks regular training did not affect the activation status of T lymphocytes measured as expression of CD69, CD25 and CCR5 in human study. Physical activity resulted in higher expression of adhesion molecule CD11c on CD16+ monocytes (especially CD14 high) without any changes in leukocytes subpopulation counts. Similar results were observed in murine model of hypertension after the training. However the training caused significant decrease of CCR5 and CD25 expressions (measured as a mean fluorescence intensity) on CD8+ T cells infiltrating perivascular adipose tissue. Our studies show modest regulatory influence of moderate training on inflammatory markers in prehypertensive subjects and murine model of Ang II induced hypertension.

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.

Chemokine RANTES is increased at early stages of coronary artery disease.

Cardiovascular diseases, and in particular coronary artery disease (CAD), are the leading causes of death in Europe and represent around 50% of overall mortality. Numerous cardiovascular markers have been proposed in relation to cardiovascular risk prediction, in relation to cardiac and vascular and cerebral events. Chemokines which regulate immune cell vascular chemotaxis, including CCL5/RANTES are points of great interest. We hypothesized that chemokine RANTES level measured in peripheral blood may be associated with severity of atherosclerosis in patients with stable angina undergoing coronary angiography. RANTES and interleukin 18 (IL-18) levels were measured by ELISA. Classical and novel cardiovascular risk factors like brachial flow mediated dilation and intima-media thickness were analyzed in the context of chemokine levels and severity of atherosclerosis. Study included 62 consecutive patients with coronary atherosclerosis demonstrated by coronary angiography, (mean age 59.3 years (S.D. = 7.4)), divided into two groups: group I with lower severity of atherosclerosis, (n = 45) and group 2 with severe CAD (n = 17) based on coronary angiography. Groups were well balanced for classic risk factors for atherosclerosis. Mean RANTES level were significantly higher in patients in group I (67.9 ng/ml, S.E.M. = 3.97) than in group II (50.5 ng/ml, S.E.M. = 7.49; P = 0.03). In contrast, IL-18 levels were similar in both groups (255 pg/ml in group I and 315 pg/ml, S.E.M. = 40.91 in group I, P = 0.12), as well as hsCRP concentration (3.45 S.E.M. = 2.66 ng/ml and 4.69 ng/ml S.E.M.= 1.64 ng/ml respectively; P = 0.47). Flow-mediated dilatation (FMD) values have been significantly lower in group II than in group I (6.31; S.E.M. = 0.61; vs 4.41; S.E.M. = 0,56, respectively, P = 0.026), while nitroglycerine-mediated dilatation (NMD) did not differ, indicating more pronounced endothelial dysfunction. No significant correlations between chemokine RANTES levels and intima-media thickness (IMT), FMD measurements have been found in the total population studied. Chemokine RANTES level could become a useful marker of severity of coronary artery disease. Its lower levels were observed in patients with more diffuse disease. Elevated level of chemokine RANTES in patients with stable angina pectoris may evaluate patients to high risk group in plaque formation at early stages of atherosclerosis.

Heterogeneity of peripheral blood monocytes, endothelial dysfunction and subclinical atherosclerosis in patients with systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is characterized by increased cardiovascular morbidity and mortality. SLE patients have increased prevalence of subclinical atherosclerosis, although the mechanisms of this observation remain unclear. Considering the emerging role of monocytes in atherosclerosis, we aimed to investigate the relationship between subclinical atherosclerosis, endothelial dysfunction and the phenotype of peripheral blood monocytes in SLE patients. METHODS: We characterized the phenotype of monocyte subsets defined by the expression of CD14 and CD16 in 42 patients with SLE and 42 non-SLE controls. Using ultrasonography, intima-media thickness (IMT) of carotid arteries and brachial artery flow-mediated dilation (FMD) as well as nitroglycerin-induced dilation (NMD) were assessed. RESULTS: Patients with SLE had significantly, but only modestly, increased IMT when compared with non-SLE controls (median (25th/75th percentile) 0.65 (0.60/0.71) mm vs 0.60 (0.56/0.68) mm; p < 0.05). Importantly, in spite of early atherosclerotic complications in the studied SLE group, marked endothelial dysfunction was observed. CD14dimCD16+proinflammatory cell subpopulation was positively correlated with IMT in SLE patients. This phenomenon was not observed in control individuals. Interestingly, endothelial dysfunction assessed by FMD was not correlated with any of the studied monocyte subsets. CONCLUSIONS: Our observations suggest that CD14dimCD16+monocytes are associated with subclinical atherosclerosis in SLE, although the mechanism appears to be independent of endothelial dysfunction.

Characterization of the impairment of the uptake of apoptotic polymorphonuclear cells by monocyte subpopulations in systemic lupus erythematosus.

Efficient removal of apoptotic polymorphonuclear leukocytes (PMNs) is an important step in the resolution of inflammation, which protects tissues from the noxious contents of dying cells. While the impairment of apoptotic PMNs removal has been demonstrated for macrophages in systemic lupus erythematosus (SLE), recent studies show that monocytes are also capable of such phagocytosis, although their involvement in SLE is not clear. Therefore, we characterized phagocytosis of apoptotic PMNs by monocytes in 22 patients with SLE and 22 healthy controls. Using flow cytometry we demonstrate that in SLE peripheral blood monocytes show impaired phagocytosis of autologous apoptotic PMNs, while they efficiently engulf apoptotic PMNs isolated from healthy subjects. Monocytes CD14highCD16+ and CD14dimCD16+ more efficiently interacted with apoptotic neutrophils than CD16- cells both in SLE and healthy subjects. Monocytes in SLE showed modestly decreased expression of CD35 and CD91 and increased expression of T Cell Ig- and mucin-domain-containing molecule-3 (TIM-3); however, these differences were evident mainly in selected subsets of monocytes (CD16+) while defects in phagocytosis were observed in all monocyte subsets. Apoptotic cell-dependent induction of lipopolysaccharide (LPS) stimulated production of anti-inflammatory cytokine IL-10 by peripheral blood mononuclear cells (PBMC) was blunted in SLE while the production of pro-inflammatory cytokine TNF-α was unchanged.

Prolactin--not only lactotrophin. A "new" view of the "old" hormone.

Prolactin (PRL) is a hormone mainly secreted by the anterior pituitary. Recent studies have shown that it may also be produced by many extrapituitary cells. The PRL gene expression is controlled by two independent promoter regions, which may be differentially regulated in the pituitary and extrapituitary organs. Proteolytic modifications of PRL generate variants of the hormone. A16 kDa PRL fragment, acting through a specific receptor, has both an antiangiogenic activity as well as an inhibitory effect on tumor growth. Stimulation of the PRL receptor involves many signal transduction pathways, for example JAK2/STAT, MAPK, c-src and Fyn kinase cascade, and these pathways may vary in different tissues. PRL synthesis and secretion is mainly regulated by the inhibitory influence of dopamine but other hormones are also involved in these mechanisms. The essential biological action of PRL is the stimulation of lactogenesis and galactopoesis. Apart from its classical functions, PRL affects other aspects of human body function including osmoregulation, metabolism and regulation of the immune and the central nervous system. Hyperprolactinemia is a common syndrome affecting both men and women. It is manifested by the presence of galactorrhoea and through the symptoms of hypogonadotrophic hypogonadism. Following on from the fact that PRL has so many pleiotropic tissue specific effects it is not surprising to learn that hyperprolactinaemia is a systemic condition which may predispose to numerous cardiovascular and immune-mediated reactions. The exact effects of PRL on both immune and cardiovascular systems are being currently unraveled and may lead to the introduction of novel therapeutic approaches in the future.

Angiotensin-(1-7) receptor Mas agonist ameliorates progress of atherosclerosis in apoE-knockout mice.

Our interest focused on an open question whether AT-(1-7), nonpeptide receptor agonist: AVE 0991, is able to ameliorate atherosclerosis. We used an apolipoprotein E (apoE) - knockout mice model of atherosclerosis. Experimental groups received the same diet as control, mixed with: AVE 0991 at a dose of 0.58 µmol/kg b.w./day, perindopril at a dose of 0.4 mg/kg b.w./day or with tiorphan at a dose of 2.5 mg/kg b.w./day. A-779 [(D-alanine)-angiotensin (1-7)] was given at a dose of 3.3 mg/kg b.w., 3 times a week i.p. Measured by "en face" method, the percentage of occupied by Sudan IV-stained surfaces were as follows: 14.2±1.9 % in control group, whereas in AVE 0991-treated as well as in perindopril-treated groups percentages were statistically significantly lower. In tiorphan group there was no change comparing to control group, whereas in A-779 group percentage was statistically significantly higher. "Cross-section" of aortic roots revealed also the difference in atherosclerotic lesions. The mean surfaces, occupied by oil red O-stained changes were: 91.213±8.123 µm(2) in control group, while in AVE 0991-treated as well as in perindopril-treated groups lesions were statistically significantly lower. In tiorphan group there was no change; however, in A-779 group lesions were statistically significantly higher. Measured by real time RT-PCR relative p22phox (submit of NADPH oxidase) expression was significantly decreased in AVE 0991-treated mice. As revealed by flow cytometry, the expression of co-stimulatory molecules: CD86, CD80 and CD40 on both dendritic cells (CD11c+) and macrophages (F4/80+) was reduced in AVE 0991-treated group, which correlated with decreased expression of CD69 activation marker on CD4+T cells. In our report we showed the beneficial effect of AVE 0991 on atherogenesis in gene-targeted mice.

Prevalence and characterization of Helicobacter pylori (H. pylori) infection and colonization in dentists.

H. pylori is an important factor in the pathogenesis of numerous diseases including gastro-intestinal, metabolic and vascular disorders. Therefore, identification of individuals at risk of this infection remains of critical importance. Dentists and dental professionals may be at increased risk due to the contact with oral cavity of patients with the presence of H. pylori in the oral cavity where it may serve as reservoir for gastric infections and participate in the pathogenesis oral mucosal lesions and ulceration. However, evidence regarding the occurrence of H. pylori infections and colonization in dentists is conflicting, but has been based mainly on serological studies, which carry significant limitations. Therefore, we attempted to characterize H. pylori infection in practising dentists in relation to the duration of their work as dental professionals. Moreover, apart from seropositivity, which was used by majority of previous studies, we have performed urea-breath test (UBT), which has been shown to represent active H. pylori infection in stomach as well as the H. pylori culture from the oral cavity. We found that while the occurrence of either gastric or oral H. pylori in dentists is not greater than in general population, it seems that in male dentists there is a greater risk of gastric H. pylori infection. Moreover, we found a relationship between the length of dentist occupation with the presence of H. pylori in gingival sulcus. In conclusion, while overall occurrence of H. pylori in dentists did not differ from that reported for stomach or oral cavity in general population, there was an increased occurrence of H. pylori in male dentists and the presence of this germ in the oral cavity appears to be related to the length of professional exposure.

Retinopathy in type 2 diabetes mellitus is associated with increased intima-media thickness and endothelial dysfunction.

BACKGROUND: Microangioathy and macroangiopathy in type 2 diabetes mellitus (T2DM) frequently coexist. Both types of vascular complications share traditional risk factors. It is not clear whether the presence of microangiopathy, such as diabetic retinopathy (DR), constitutes a predictor of atherosclerosis in T2DM. Here we described the search for the association between DR and intima-media thickness (IMT) in T2DM. We also compared endothelial function in subjects with and without DR. MATERIAL AND METHODS: We examined 182 consecutive patients with T2DM for at least 5 years (mean age at examination 56.3 +/- 6.52 years). We assessed (i) IMT of carotid artery by ultrasound and (ii) endothelial function by flow-mediated dilatation (FMD) method as well as by measurement of concentrations of von Willebrand factor (vWF) and s-ICAM-1. All patients underwent ophthalmological examination. Statistical analysis included Student's, Mann-Whitney, chi-square, Fisher tests and multiple regression. RESULTS: DR was found in 71 (39.0%) subjects. IMT was higher in patients with DR than those without DR (0.87 mm vs. 0.79 mm, respectively, P = 0.0001). FMD was lower in the complication group than in subjects without DR (8.38% vs. 10.45%, respectively, P = 0.0023). Concentrations of s-ICAM-1 and vWF were not different between the groups. In multiple regression analysis, DR was among the predictors of increased IMT (P = 0.016) and decreased FMD (P = 0.002). We did not find a significant association of DR with vWF and s-ICAM-1 (P = 0.09 and P = 0.11, respectively). CONCLUSIONS: DR is associated with increased IMT and endothelial dysfunction in T2DM. Impaired endothelial function may be a common denominator of pathogenesis of microvascular complications and atherosclerosis in T2DM.

NADPH oxidase and uncoupled nitric oxide synthase are major sources of reactive oxygen species in oral squamous cell carcinoma. Potential implications for immune regulation in high oxidative stress conditions.

The development of cancer is associated with high oxidative stress and at the same time with immune system activation. Tumors develop efficient mechanisms of protection against the immune response, which allow them to escape the immune surveillance. Simultaneously, key events in the process of carcinogenesis are related to oxidative stress. The relationship between the two remains unknown. Novel understanding of oxidative stress shows that discrete changes of activities of certain enzyme systems such as NADPH oxidases or nitric oxide synthases may be more important than the overall balance of production and removal of reactive oxygen species. Such imbalance of nitric oxide and superoxide production could modify inflammation and immune regulation. We studied superoxide anion production (by lucigenin enhanced chemiluminescence - 5 microM), NADPH oxidase activity and nitric oxide synthase (NOS) dysfunction. In parallel mRNA expression of immunomodulatory markers such as FoxP3 (T regulatory cell marker), CCR6 (mucosal homing effector T cell marker) and CD85j (NK cell/CD8 T cell Ig-like MHC class I inhibitory receptor) was determined. Basal superoxide production and NADPH oxidase activity are increased in oral squamous cell carcinoma. Tumor superoxide production was inhibited by NADPH oxidase inhibitor apocynin and by NOS inhibitor L-NAME. This indicates, for the first time, that oral squamous cell carcinoma is characterized by dysregulated nitric oxide synthase, which apart from increased NADPH oxidase activity contributes to oxidative stress and may be related to the immuno-pathology of these tumors. Studied tumors were infiltrated by CCR6+, but showed lower expression of both CD85j and FoxP3 mRNA. Finally, the CD85j mRNA expression was inversely correlated to oxidative stress parameters. These preliminary studies indicate that tumor oxidative stress, related to NADPH oxidase activity and NOS activity could be related to immune responses to cancer, thus therapeutic modification of oxidative stress, which could include the correction of NOS dysfunction, could facilitate immune surveillance.

Perivascular adipose tissue as a messenger of the brain-vessel axis: role in vascular inflammation and dysfunction.

Perivascular adipose tissue AT is a critical regulator of vascular function, which until recently has been greatly overlooked. Virtually all arteries are surrounded by a significant amount of perivascular adipose tissue, which has long been considered to serve primarily a supportive, mechanical purpose. Recent studies show that both visceral and perivascular fat is a very active endocrine and paracrine source of inflammatory cytokines and adipokines. The latter include beneficial adipocytokines such as adiponectin or so far unidentified adipocyte derived relaxing factor (ADRF) as the presence of perivascular AT may decrease contractile responses to vasoconstrictive agents. However, in pathological states such as obesity, hypertension, diabetes metabolic syndrome and other cardiovascular disorders perivascular tissue becomes dysfunctional and production of protective factors diminishes while detrimental adipocytokines such as leptin, resistin, IL-6, TNF-alpha or IL-17 increases. Moreover the dysfunction of perivascular fat can lead to imbalance between vascular nitric oxide (NO) and superoxide production. Adipokines also regulate immune system as chemokines (such as MIP-1 or RANTES) and induce inflammation with infiltration of T cells and macrophages to the vessel wall. Interestingly central nervous system can affect vascular function through mediation of perivascular adipose tissue dysfunction. In particular sympathetic nervous system endings are present in both visceral and perivascular AT. This powerful relationship between the brain and the vessel can be termed "brain-vessel axis" in which--we propose in the Review--perivascular adipose tissue may take center stage. The role of perivascular fat in the regulation of blood vessels depends on metabolic state, inflammation and clinical risk factors. In health protective and vasorelaxant properties of perivascular AT dominate while in pathology pathogenetic influences including neural stimulation of sympathetic nerve endings or humoral effects of certain hormones and adipocytokines dominates. We propose to term this state "perivascular adipose tissue dysfunction" in similarity to endothelial dysfunction.

Inhibition of five lipoxygenase activating protein (FLAP) by MK-886 decreases atherosclerosis in apoE/LDLR-double knockout mice.

BACKGROUND: Recent reports point to an important role of leukotrienes in atherogenesis. Leukotrienes are produced by 5-lipoxygenase co-operating with five lipoxygenase activating protein (FLAP). We hypothesized that MK-886, an inhibitor of FLAP, could attenuate the development of atherosclerosis in the atherogenic apolipoprotein E/low density lipoprotein receptor (apoE/LDLR) double knockout (DKO) mouse model. MATERIALS AND METHODS: Female apoE/LDLR-DKO mice at the age of 8 weeks were put on Western diet. The experimental group (n = 10) received the same diet as the control group (n = 10), but mixed with MK-886 (Merck, Rahway, NJ) at a dose of 4 microg per 100 mg of body-weight per day. At age 6 months the mice were sacrificed under anaesthesia. RESULTS: Measured by the en face method, the percentage of area occupied by lesions in aortas in the control group was 25.15 +/- 2.9%, whereas in the MK-886-treated group it was 11.16 +/- 0.7% (P < 0.05). Lesion area measured by cross-section of aortic roots was 455,494 +/- 29,564 microm(2) in the control group versus 263,042 +/- 20,736 microm(2) in the MK-886-treated group (P < 0.05). The MK-886 did not change the plasma cholesterol lipoprotein profile as compared with the control mice. Finally, we show that MK-886 may increase plaque stability by decreasing the macrophage content as well as increasing the collagen and smooth-muscle cell content. CONCLUSIONS: Our results show for the first time that inhibition of FLAP by MK-886 reduces development of atherosclerosis in gene-targeted apoE/LDLR-DKO mice.

Adipocytokines - novel link between inflammation and vascular function?

Obesity and obesity related diseases are a major public health problem. Recent studies have shown that fat tissue is not a simple energy storage organ, but exerts important endocrine and immune functions. These are achieved predominantly through release of adipocytokines, which include several novel and highly active molecules released abundantly by adipocytes like leptin, resistin, adiponectin or visfatin, as well as some more classical cytokines released possibly by inflammatory cells infiltrating fat, like TNF-alpha, IL-6, MCP-1 (CCL-2), IL-1. All of those molecules may act on immune cells leading to local and generalized inflammation and may also affect vascular (endothelial) function by modulating vascular nitric oxide and superoxide release and mediating obesity related vascular disorders (including hypertension, diabetes, atherosclerosis, and insulin resistance) but also cancer or non-alcoholic fatty liver diseases. Present review, in a concise form, focuses on the effects of major adipocytokines, characteristic for adipose tissue like leptin, adiponectin, resistin and visfatin on the immune system, particularly innate and adaptive immunity as well as on blood vessels. Macrophages and T cells are populating adipose tissue which develops into almost an organized immune organ. Activated T cells further migrate to blood vessels, kidney, brain and other organs surrounded by infiltrated fat leading to their damage, thus providing a link between metabolic syndrome, inflammation and cardiovascular and other associated disorders. Ceretain treatments may lead to significant changes in adipocytokine levels. For example include beta-2 adrenoreceptor agonists, thiazolidinediones as well as androgens lead to decrease of plasma leptin levels. Moreover future treatments of metabolic system associated disorders should focus on the regulation of adipocytokines and their modes of action.

Effects of novel plant antioxidants on platelet superoxide production and aggregation in atherosclerosis.

Superoxide anion is produced in human platelets predominantly by Nox2-dependent NADPH oxidases. In vitro experiments have shown that it might play a role in modulating platelet functions. The relationship between platelet superoxide production and aggregation remains poorly defined. Accordingly, we aimed to study superoxide production and aggregation in platelets from subjects with significant cardiovascular risk factors (hypertension, hypercholesterolemia, smoking and diabetes mellitus) and from control individuals. Moreover, we studied the effects of novel polyphenol-rich extracts of Aronia melanocarpa (chokeberry) berries on platelet function in vitro. Superoxide production was significantly increased in patients with cardiovascular risk profile when compared to controls, while platelet aggregation in response to either collagen or thrombin were borderline higher, and did not reach statistical significance. Interestingly, no relationship was observed between platelet aggregation ex vivo and platelet superoxide production in either of studied groups. No correlation was found between endothelial function (measured by FMD) and platelet aggregation ex vivo either. Polyphenol-rich extracts of A. melanocarpa berries caused a significant concentration dependent decrease in superoxide production only in patients with cardiovascular risk factors, while no effect was observed in the control group. A. melanocarpa extracts abolished the difference in superoxide production between risk factor patients and controls. A. melanocarpa extracts exerted significant concentration dependent anti-aggregatory effects in both studied groups, which indicated that these effects may be independent of it's ability to modulate superoxide production. The anti-aggregatory effects of chokeberry extracts were similar irrespective of aggregation inducing agent (collagen or thrombin). Moreover, they appear to be independent of platelet NO release as NOS inhibition by L-NAME did not lead to their abrogation.