A validated UHPLC-MS/MS method for the measurement of riluzole in plasma and myocardial tissue samples.

Through blocking the cardiac persistent sodium current, riluzole has the potential to prevent myocardial damage post cardiac bypass surgery. A sensitive UHPLC-MS/MS method was developed and validated for quantitation of riluzole and 5-methoxypsoralen in human plasma and myocardial tissue homogenate using a liquid-liquid extraction with dichloromethane. The chromatographic separation was achieved using Shimadzu Shim-pack XR-ODS III, 2.0 × 50 mm, 1.6 µm column with a gradient mobile phase comprising methanol and ammonium acetate buffer pH 3.6 in purified water. The analyte and internal standard were separated within 3.5 min. Riluzole quantitation was achieved using the mass transitions of 235-138 for riluzole and 217-156 for 5-methoxypsoralen. The method was linear for riluzole plasma concentrations from 0.2 to 500 ng/mL and myocardial tissue homogenate concentrations from 0.2 to 100 ng/mL. The method developed was successfully applied to a clinical study for patients receiving riluzole while undergoing cardiac bypass surgery.

Developmental cardiovascular physiology of the olive ridley sea turtle (Lepidochelys olivacea).

Our understanding of reptilian cardiovascular development and regulation has increased substantially for two species the American alligator (Alligator mississippiensis) and the common snapping turtle (Chelydra serpentina) during the past two decades. However, what we know about cardiovascular maturation in many other species remains poorly understood or unknown. Embryonic sea turtles have been studied to understand the maturation of metabolic function, but these studies have not addressed the cardiovascular system. Although prior studies have been pivotal in characterizing development, and factors that influence it, the development of cardiovascular function, which supplies metabolic function, is unknown in sea turtles. During our investigation we focused on quantifying how cardiovascular morphological and functional parameters change, to provide basic knowledge of development in the olive ridley sea turtle (Lepidochelys olivacea). Embryonic mass, as well as mass of the heart, lungs, liver, kidney, and brain increased during turtle embryo development. Although heart rate was constant during this developmental period, arterial pressure approximately doubled. Further, while embryonic olive ridley sea turtles lacked cholinergic tone on heart rate, there was a pronounced beta adrenergic tone on heart rate that decreased in strength at 90% of incubation. This beta adrenergic tone may be partially originating from the sympathetic nervous system at 90% of incubation, with the majority originating from circulating catecholamines. Data indicates that olive ridley sea turtles share traits of embryonic functional cardiovascular maturation with the American alligator (Alligator mississippiensis) but not the common snapping turtle (Chelydra serpentina).

Inflammatory interaction between LIGHT and proteinase-activated receptor-2 in endothelial cells: potential role in atherogenesis.

The interaction between inflammatory cytokines and endothelial cells is a critical step in atherogenesis leading to endothelial dysfunction and inflammation. We have previously reported that the tumor necrosis factor superfamily member LIGHT could be involved in atherogenesis through its ability to promote vascular inflammation. In the present study we identified proteinase-activated receptor (PAR)-2 as an inflammatory mediator that was markedly enhanced by LIGHT in endothelial cells. We also found that LIGHT acted synergistically with PAR-2 activation to promote enhanced release of the proatherogenic chemokines interleukin-8 and monocyte chemoattractant protein-1, underscoring that the interaction between LIGHT and PAR-2 is biologically active, promoting potent inflammatory effects. We showed that the LIGHT-mediated upregulation of PAR-2 in endothelial cells is mediated through the HVEM receptor, involving Jun N-terminal kinase signaling pathways. A LIGHT-mediated upregulation of PAR-2 mRNA levels was also found in human monocytes when these cells were preactivated by tumor necrosis factor alpha. We have previously demonstrated increased plasma levels of LIGHT in unstable angina patients, and here we show a similar pattern for PAR-2 expression in peripheral blood monocytes. We also found that LIGHT, LIGHT receptors, and PAR-2 showed enhanced expression, and, to some degree, colocalization in endothelial cells and macrophages, in the atherosclerotic plaques of ApoE(-/-) mice, suggesting that the inflammatory interaction between LIGHT and PAR-2 also may be operating in vivo within an atherosclerotic lesion. Our findings suggest that LIGHT/PAR-2-driven inflammation could be a pathogenic loop in atherogenesis potentially representing a target for therapy in this disorder.

Soluble CXCL16 predicts long-term mortality in acute coronary syndromes.

BACKGROUND: CXCL16/SR-PSOX is an interferon-gamma-regulated chemokine and scavenger receptor for oxidized low-density lipoprotein that is expressed in atherosclerotic lesions. Proteolytic cleavage of membrane-bound CXCL16 releases soluble CXCL16, which may promote migration of effector T cells and augment a proatherogenic inflammatory response. We hypothesized that soluble CXCL16 concentrations are associated with long-term outcome in patients with acute coronary syndromes. METHODS AND RESULTS: We assessed the association between circulating CXCL16 levels obtained within 24 hours after admission and time to death in 1351 patients (median age 67 years, 30% female) with a diagnosis of unstable angina, non-ST-segment-elevation myocardial infarction, or ST-segment-elevation myocardial infarction. During a median follow-up time of 81 months, 377 patients died. Increased levels of CXCL16 were prognostically unfavorable; the fourth versus first quartile was associated with higher risk of death (hazard ratio 2.1; 95% CI 1.6 to 2.8; P<0.0001), triple risk of developing heart failure (hazard ratio 3.0; 95% CI 1.8 to 5.1; P<0.0001), and a doubling of the risk of rehospitalization for myocardial infarction (hazard ratio 2.1; 95% CI 1.3 to 3.3; P=0.002). After adjustment for conventional risk markers, logarithmically transformed CXCL16 level remained a strong independent indicator of long-term mortality (hazard ratio 1.21; 95% CI 1.09 to 1.36 per 1 SD increase in CXCL16; P=0.0006) and congestive heart failure development (hazard ratio 1.25; 95% CI 1.05 to 1.48; P=0.01). In a subsample of 714 patients, after further adjustment for troponin T, high-sensitive C-reactive protein, pro-B-type natriuretic peptide, and left ventricular ejection fraction, CXCL16 still provided significant additional prognostic information on mortality (hazard ratio 1.21; 95% CI 1.02 to 1.42 per 1 SD increase in CXCL16; P=0.02). CONCLUSIONS: In patients with an acute coronary syndrome, CXCL16 levels obtained within 24 hours of admission are associated with long-term mortality after adjustment for other risk factors.

Elevated levels of activin A in clinical and experimental pulmonary hypertension.

Activin A, a member of the transforming growth factor (TGF)-beta superfamily, is involved in regulation of tissue remodeling and inflammation. Herein, we wanted to explore a role for activin A in pulmonary hypertension (PH). Circulating levels of activin A and its binding protein follistatin were measured in patients with PH (n = 47) and control subjects (n = 14). To investigate synthesis and localization of pulmonary activin A, we utilized an experimental model of hypoxia-induced PH. In mouse lungs, we also explored signaling pathways that can be activated by activin A, such as phosphorylation of Smads, which are mediators of TGF-beta signaling. Possible pathophysiological mechanisms initiated by activin A were explored by exposing pulmonary arterial smooth muscle cells in culture to this cytokine. Elevated levels of activin A and follistatin were found in patients with PH, and activin A levels were significantly related to mortality. Immunohistochemistry of lung autopsies from PH patients and lungs with experimental PH localized activin A primarily to alveolar macrophages and bronchial epithelial cells. Mice with PH exhibited increased pulmonary levels of mRNA for activin A and follistatin in the lungs, and also elevated pulmonary levels of phosphorylated Smad2. Finally, we found that activin A increased proliferation and induced gene expression of endothelin-1 and plasminogen activator inhibitor-1 in pulmonary artery smooth muscle cells, mediators that could contribute to vascular remodeling. Our findings in both clinical and experimental studies suggest a role for activin A in the development of various types of PH.

A potential role of the CXC chemokine GROalpha in atherosclerosis and plaque destabilization: downregulatory effects of statins.

OBJECTIVE: We examined the role of the CXCR2 ligand growth-related oncogene (GRO) alpha in human atherosclerosis. METHODS AND RESULTS: GROalpha levels were examined by enzyme immunoassay, real-time quantitative RT-PCR, and cDNA microarrays. The in vitro effect of statins on GROalpha was examined in endothelial cells and THP-1 macrophages. Our main findings were: (1) GROalpha was among the 10 most differentially expressed transcripts comparing peripheral blood mononuclear cells (PBMCs) from patients with coronary artery disease (CAD) and healthy controls. (2) Both patients with stable (n=41) and particularly those with unstable (n=47) angina had increased plasma levels of GROalpha comparing controls (n=20). (3) We found increased expression of GROalpha within symptomatic carotid plaques, located to macrophages and endothelial cells. (4) GROalpha enhanced the release of matrix metalloproteinases in vascular smooth muscle cells, and increased the binding of acetylated LDL in macrophages. (5) Atorvastatin downregulated GROalpha levels as shown both in vitro in endothelial cells and macrophages and in vivo in PBMCs from CAD patients. (6) The effect on GROalpha in endothelial cells involved increased storage and reduced secretion of GROalpha. CONCLUSIONS: GROalpha could be involved in atherogenesis and plaque destabilization, potentially contributing to inflammation, matrix degradation, and lipid accumulation within the atherosclerotic lesion.

High levels and inflammatory effects of soluble CXC ligand 16 (CXCL16) in coronary artery disease: down-regulatory effects of statins.

AIMS: CXC ligand 16 (CXCL16) may be involved in inflammation and lipid metabolism, and we hypothesized a role for this chemokine in coronary artery disease (CAD). METHODS AND RESULTS: We performed clinical studies in CAD patients as well as experimental studies in cells with relevance to atherogenesis [i.e. endothelial cells, vascular smooth muscle cells (SMC), and peripheral blood mononuclear cells (PBMC)]. We also examined the ability of HMG-CoA reductase inhibitors (statins) to modulate CXCL16 levels both in vivo and in vitro. Our main findings were: (i) patients with stable (n = 40) and unstable (n = 40) angina had elevated plasma levels of CXCL16 compared with controls (n = 20); (ii) low-dose simvastatin (20 mg qd, n = 15) and high-dose atorvastatin (80 mg qd, n = 9) down-regulated plasma levels of CXCL16 during 6 months of therapy; (iii) in vitro, atorvastatin significantly decreased the interleukin (IL)-1beta-mediated release of CXCL16 from PBMC and endothelial cells; (iv) attenuating effect of atorvastatin on the IL-1beta-mediated release of CXCL16 in PBMC seems to involve post-transcriptional modulation as well as down-regulation of CXCL16 release through inhibition of the protease a disintegrin and metalloproteinase 10 (ADAM10); (v) soluble CXCL16 increased the release of IL-8, monocyte chemoattractant peptide 1, and matrix metalloproteinases in vascular SMC and increased the release of IL-8 and monocyte chemoattractant peptide 1 in PBMC, with particularly enhancing effects in cells from CAD patients. CONCLUSION: Our findings suggest that soluble CXCL16 could be linked to atherogenesis not only as a marker of inflammation, but also as a potential inflammatory mediator.

Increased expression of visfatin in macrophages of human unstable carotid and coronary atherosclerosis: possible role in inflammation and plaque destabilization.

BACKGROUND: Although the participation of inflammation in atherogenesis is widely recognized, the identification of the different components has not been clarified. In particular, the role of inflammation in plaque destabilization is not fully understood. METHODS AND RESULTS: Our main findings were as follows: (1) In a microarray experiment, we identified visfatin, one of the most recently identified adipokines, as a gene that was markedly enhanced in carotid plaques from symptomatic compared with plaques from asymptomatic individuals. This finding was confirmed when carotid plaques from 7 patients with asymptomatic and 14 patients with symptomatic lesions were examined with real-time reverse transcription polymerase chain reaction. (2) Immunohistochemistry showed that visfatin was localized in areas that were rich in lipid-loaded macrophages. (3) The relationship between visfatin and unstable lesions was also found in patients with coronary artery disease, demonstrating a strong visfatin immunostaining in lipid-rich regions within the material obtained at the site of plaque rupture in patients with acute myocardial infarction. (4) Both oxidized low-density lipoprotein and tumor necrosis factor-alpha increased visfatin expression in THP-1 monocytes, with a particularly enhancing effect when these stimuli were combined. (5) Visfatin increased matrix metalloproteinase-9 activity in THP-1 monocytes and tumor necrosis factor-alpha and interleukin-8 levels in peripheral blood mononuclear cells. Both of these effects were abolished when insulin receptor signaling was blocked. CONCLUSIONS: Our findings suggest that visfatin should be regarded as an inflammatory mediator, localized to foam cell macrophages within unstable atherosclerotic lesions, that potentially plays a role in plaque destabilization.

The complex role of T-cell-based immunity in atherosclerosis.

Although the pathogenic role of T cells in atherogenesis is well established, the function of the various T-cell subsets is far from clear. Whereas activation of the T-helper type 1 (Th1) subset promotes inflammatory and proatherogenic responses and activation of Th2 cells mediates both proatherogenic and antiatherogenic effects, the newly discovered regulatory T-cell subset seems to attenuate atherogenesis. However, the dynamics of T-cell response within the plaque are still poorly understood, and both antigen-dependent and antigen-independent stimuli may be involved in the expansion of T cells in atherosclerotic plaques. Nevertheless, the different nature of the various T-cell subsets and their complex role in atherogenesis underscore the need for future research in this field of atheroimmunology. This research is not only of interest for the basic research field, but may also have relevance for clinical cardiology, potentially leading to new targets for therapy in atherosclerotic disorders.

Enhanced expression of the homeostatic chemokines CCL19 and CCL21 in clinical and experimental atherosclerosis: possible pathogenic role in plaque destabilization.

OBJECTIVE: Based on their role in T-cell homing into nonlymphoid tissue, we examined the role of the homeostatic chemokines CCL19 and CCL21 and their common receptor CCR7 in coronary artery disease (CAD). METHODS AND RESULTS: We performed studies in patients with stable (n=40) and unstable (n=40) angina and healthy controls (n=20), in vitro studies in T-cells and macrophages, and studies in apolipoprotein-E-deficient (ApoE-/-) mice and human atherosclerotic carotid plaques. We found increased levels of CCL19 and CCL21 within the atherosclerotic lesions of the ApoE-/- mice, in human atherosclerotic carotid plaques, and in plasma of CAD patients. Whereas strong CCR7 expression was seen in T-cells from murine and human atherosclerotic plaques, circulating T-cells from angina patients showed decreased CCR7 expression. CCL19 and CCL21 promoted an inflammatory phenotype in T-cells and macrophages and increased matrix metalloproteinase (MMP) and tissue factor levels in the latter cell type. Although aggressive statin therapy increased CCR7 and decreased CCL19/CCL21 levels in peripheral blood from CAD patients, conventional therapy did not. CONCLUSIONS: The abnormal regulation of CCL19 and CCL21 and their common receptor in atherosclerosis could contribute to disease progression by recruiting T-cells and macrophages to the atherosclerotic lesions and by promoting inflammatory responses in these cells.

Chemokines in cardiovascular risk prediction.

In consideration of the important role of inflammation in plaque progression and stability, recent work has focused on whether plasma markers of inflammation can non-invasively diagnose and predict coronary artery disease (CAD) and other forms of atherosclerotic disorders. Although several studies support an important pathogenic role of chemokines in atherogenesis and plaque destabilization, potentially representing attractive therapeutic targets in atherosclerotic disorders, this does not necessarily mean that chemokines are suitable parameters for risk prediction. In fact, the ability to reflect up-stream inflammatory activity, stable levels in individuals and high stability of the actual protein (e.g. long half-life and negligible circadian variation), are additional important criteria for an ideal biomarker in cardiovascular disease. Although plasma/serum levels of certain chemokines (e.g. interleukin 8 and monocyte chemoattractant protein-1) have been shown to be predictive for future cardiac events in some studies, independent of traditional cardiovascular risk factors and C-reactive protein, and although certain gene polymorphisms of chemokines/chemokine receptors (e.g. fractalkine receptor) have been shown to be predictive of future atherosclerotic disease, further prospective studies, including a larger number patients, are needed to make any firm conclusion. While the demonstrations of an association between chemokines and CAD are a necessary first step, such studies do not establish the full clinical utility of a biomarker, which is a more demanding process that requires validation in multiple cohorts, and clear demonstration of incremental prognostic value over traditional risk models. If successful, such new biomarker will be a useful indicator for better risk assessment, diagnosis, and prognosis, as well as monitoring pharmacological treatments for atherosclerosis.

Enhanced T-cell expression of RANK ligand in acute coronary syndrome: possible role in plaque destabilization.

OBJECTIVE: Based on its role in inflammation and matrix degradation, we hypothesized a role for osteoprotegerin (OPG), RANK, and RANK ligand (RANKL) in coronary artery disease. METHODS AND RESULTS: We examined the expression of various members of the OPG/RANKL/RANK axis in patients with stable and unstable angina and in the atherosclerotic lesions of apolipoprotein E-deficient (apoE(-/-)) mice. Our findings were: (1) Serum levels of OPG were raised in patients with unstable angina (n=40), but not in those with stable angina (n=40), comparing controls (n=20); (2) mRNA levels of RANKL were increased in T-cells in unstable angina patients accompanied by increased expression of RANK in monocytes; (3) strong immunostaining of OPG/RANKL/RANK was seen within thrombus material obtained at the site of plaque rupture during acute myocardial infarction; (4) OPG/RANKL/RANK was expressed in the atherosclerotic plaques of apoE(-/-) mice, with RANKL located specifically to the plaques; and (5) RANKL enhanced the release of monocyte chemoattractant peptide-1 in mononuclear cells from unstable angina patients, and promoted matrix metalloproteinase (MMP) activity in vascular smooth muscle cells. CONCLUSIONS: We show enhanced expression of the OPG/RANKL/RANK system both in clinical and experimental atherosclerosis, with enhanced T-cell expression of RANKL as an important feature of unstable disease.

Enhanced plasma levels of LIGHT in unstable angina: possible pathogenic role in foam cell formation and thrombosis.

BACKGROUND: Numerous studies have demonstrated the ability of oxidized LDL [(ox)LDL] to promote an inflammatory response in macrophages. Several inflammatory mediators have been reported to increase after oxLDL stimulation of such cells, but their relative importance is still unknown. In the present study, we used microarrays to identify genes in THP-1 macrophages that were upregulated by oxLDL. METHODS AND RESULTS: Our main findings were as follows. In a microarray screening experiment, we identified LIGHT, a ligand in the tumor necrosis factor superfamily, as one of the genes that were markedly upregulated in oxLDL-stimulated THP-1 macrophages. We showed significantly raised plasma levels of LIGHT in patients with stable angina (n=40) and particularly in those with unstable angina (n=40) compared with healthy controls (n=20), which underscores the clinical relevance of the in vitro finding. We also showed that LIGHT enhanced lipid accumulation in oxLDL-stimulated THP-1 macrophages, possibly through upregulation of class A scavenger receptor (SR-A). This increased lipid accumulation was accompanied by enhanced expression of tissue factor and plasminogen activator inhibitor-1, as well as enhanced thrombin formation, transforming macrophages into a prothrombotic phenotype. The LIGHT-mediated increase in SR-A, tissue factor, and plasminogen activator inhibitor-1 was also seen in human monocyte-derived macrophages. Finally, the LIGHT-mediated enhancement of SR-A and TF expression appears to involve nuclear factor-kappaB activation. CONCLUSIONS: These findings suggest that LIGHT could serve as a molecular link between lipid metabolism, inflammation, and thrombus formation, which are all features of atherosclerotic plaques.

Expression of fractalkine (CX3CL1) and its receptor, CX3CR1, is elevated in coronary artery disease and is reduced during statin therapy.

OBJECTIVE: Recent data derived primarily from studies in animal models suggest that fractalkine (CX3CL1) and its cognate receptor, CX3CR1, play a role in atherogenesis. We, therefore, hypothesized that enhanced CX3CL1/CX3CR1 expression may promote atherogenesis in patients with coronary artery disease (CAD). METHODS AND RESULTS: We examined the plasma levels of CX3CL1 and CX3CR1 expression in peripheral blood mononuclear cells (PBMC) in various CAD populations (30 patients with previous myocardial infarction, 40 patients with stable angina, 40 patients with unstable angina, and a total of 35 controls) and used various experimental approaches to characterize CX3CL1-mediated leukocyte responses. We found that the plasma levels of CX3CL1 are greatly increased in CAD, particularly in unstable disease. The parallel increase of CX3CR1 expression in PBMC was predominantly attributable to an expansion of the (CX3CR1+)(CD3+)(CD8+) T cell subset and was associated with enhanced chemotactic, adhesive, and inflammatory responses to CX3CL1. Statin therapy for 6 months reduced the expression of CX3CL1 and CX3CR1, reaching statistical significance for both parameters only during aggressive (atorvastatin, 80 mg qd) but not conventional (simvastatin, 20 mg qd) therapy. Consequently, the functional responses of the PBMC to CX3CL1 including migration, adhesion, and secretion of interleukin-8 were attenuated by the treatments. CONCLUSIONS: Our results suggest that the CX3CL1/CX3CR1 dyad may contribute to atherogenesis and plaque destabilization in human CAD.

Increased expression of interleukin-1 in coronary artery disease with downregulatory effects of HMG-CoA reductase inhibitors.

BACKGROUND: Inflammation is important in atherogenesis. Interleukin (IL)-1 is the prototypic inflammatory cytokine. We hypothesized a dysbalance between inflammatory and anti-inflammatory mediators in the IL-1 family in coronary artery disease (CAD) and a possible modulation of these mediators by HMG-CoA inhibitors (statins). METHODS AND RESULTS: In a microarray screening experiment examining peripheral blood mononuclear cells (PBMCs) from 6 CAD patients and 4 healthy control subjects, IL-1beta was identified as 1 of 25 genes whose expression were upregulated in CAD and downregulated by statins. In the following, we studied the role of IL-1beta and related mediators in CAD. Our major findings were as follows. (1) Although mRNA levels of IL-1alpha and IL-1beta were markedly reduced in PBMCs from CAD patients after 6 months of simvastatin (20 mg/d, n=15) and atorvastatin (80 mg/d, n=15) therapy, the reduction in IL-1 receptor antagonist (IL-1Ra) was more modest. Statins also reduced the spontaneous release of IL-1beta and IL-1Ra from PBMCs in CAD patients. (2) mRNA levels of IL-1alpha, IL-1beta, and IL-1Ra were increased in PBMCs from patients with stable (n=20) and unstable (n=20) angina compared with healthy control subjects (n=15). Although the unstable patients had particularly high levels of IL-1beta and IL-1alpha, IL-1Ra was not correspondingly increased. (3) IL-1beta induced release of proatherogenic cytokines from PBMCs, whereas atorvastatin partly abolished this effect. CONCLUSIONS: Our findings suggest that cytokines in the IL-1 family may represent therapeutic targets in CAD. The ability of statins to modulate these cytokines in an anti-inflammatory direction underscores their immunomodulatory potential.

Potential anti-inflammatory role of activin A in acute coronary syndromes.

OBJECTIVES: We sought to investigate whether activin A could be involved in the immunopathogenesis of acute coronary syndromes. BACKGROUND: Inflammatory mechanisms seem to play a pathogenic role in atherosclerosis and acute coronary syndromes, but the actual mediators have not been fully identified. Activin A, a pleiotropic member of the transforming growth factor-beta cytokine family, has recently been suggested to play a role in inflammation. METHODS: We examined the role of activin A and its endogenous inhibitor follistatin in patients with stable (n = 26) and unstable angina (n = 20) and healthy control subjects (n = 20) by different experimental approaches. RESULTS: 1) Patients with stable angina had raised activin A concentrations, as assessed by protein levels in serum and messenger ribonucleic acid levels in peripheral blood mononuclear cells (PBMCs). 2) Although several activin A-related mediators were upregulated in PBMCs from patients with stable angina compared with controls (i.e., activin A and Smad3), no changes or even downregulation (i.e., Smad2) were seen in unstable disease. 3) The activin type II receptors, representing the primary ligand-binding proteins, were downregulated in unstable compared with stable angina. 4) Percutaneous coronary intervention induced a decrease in the activin A/follistatin ratio, suggesting downregulatory effects on activin A activity. 5) Although activin A dose-dependently suppressed the release of inflammatory cytokines from PBMCs in angina patients, an opposite effect was found in healthy controls. CONCLUSIONS: Our findings suggest an anti-inflammatory potential of activin A in angina patients, and such effects may be of particular relevance in unstable angina in which several of the activin parameters were downregulated.

Use of a substrate/alliinase combination to generate antifungal activity in situ.

Allicin, an active ingredient of garlic, possesses a range of antimicrobial properties. Unfortunately, certain properties of the compound, such as chemical instability and low miscibility with water, have hampered its practical use in the past. Here, we show that it is possible to use a binary system consisting of the plant enzyme alliinase and its substrate alliin to generate allicin, and hence antifungal activity, in situ. During application, the two inactive components generate compounds that inhibit growth and infection-related development of the rice blast fungus Magnaporthe grisea. It is therefore possible to "trigger" biological activity in a controlled, yet effective manner. Apart from circumventing many of the drawbacks of allicin, this binary system has additional important advantages, such as low toxicity of its individual components and selective activation. Importantly, alliinase is also able to use different substrates, therefore paving the way to a range of novel, binary antimicrobial systems with custom-made chemical and biochemical properties.

Effect of activated platelets on expression of cytokines in peripheral blood mononuclear cells - potential role of prostaglandin E2.

Platelets may act as inflammatory cells. To study the effects of soluble and cell-bound platelet factors on the expression of several cytokines and related mediators in leukocytes, peripheral blood mononuclear cells (PBMC) were incubated with platelet-free supernatants from SFLLRN-activated platelet-rich plasma (PRP) or SFLLRN-activated PRP in itself. Our main findings were: (i) the gene expression of several chemokines and some cytokines were markedly increased by both activated PRP and supernatants, as also confirmed at the protein level for IL-6, IL-8 and MIP-1alpha; (ii) the selective protein kinase A type I (PKAI) antagonist Rp-8-Br-cAMP reduced this platelet-induced expression of IL-6, IL-8 and MIP-1alpha in PBMC, suggesting a role of cAMP/PKAI mediated mechanisms in this interaction; (iii) PGE(2) dose-dependently increased the release of IL-6, IL-8 and MIP-1alpha from PBMC mimicking the effect of activated platelets. Furthermore, activated platelets released comparable amounts of PGE(2), suggesting that platelet-derived PGE2 could interact with PBMC in co-cultures; (iv) IL-10 inhibited the platelet-inducing effect on IL-6, IL-8 and MIP-1alpha in PBMC, and notably, the addition PGE2 totally abolished this IL-10 effect suggesting that the suppressive effect of IL-10 on the plateletinduced activation of PBMC might at least partly involve PGE(2) related mechanisms. The present study supports a view of platelets as inflammatory cells, and suggests a potential role of platelet-derived PGE(2) in platelet-induced inflammatory responses.

Activin A and cardiovascular disease in type 2 diabetes mellitus.

BACKGROUND: Silent coronary artery disease is a frequent complication of type 2 diabetes (T2DM). Based on its multiple roles in inflammation, atherogenesis and glucose homeostasis, we hypothesised that activin A could be related to coronary atherosclerosis in T2DM. METHODS: Activin A and follistatin were measured in 102 patients with T2DM and 20 age- and sex-matched healthy controls. Coronary angiography was performed in a sub-population of patients and associations with activin A were examined using multiple linear regression. RESULTS: Serum activin A and the activin A/follistatin ratio were increased in patients with T2DM and coronary artery disease (CAD) compared with healthy volunteers and the elevated activin A was associated with the severity of coronary atherosclerotic burden as determined by the proportion of ≥2 vessel disease (p = 0.035) after multivariable-adjusted trend analysis. No significant association between presence of CAD or extent score and activin A was observed. CONCLUSION: In patients with T2DM, increased activin A may reflect chronic underlying pathophysiological processes involved in development of cardiovascular disease.

Activin A levels are associated with abnormal glucose regulation in patients with myocardial infarction: potential counteracting effects of activin A on inflammation.

OBJECTIVE: On the basis of the role of activin A in inflammation, atherogenesis, and glucose homeostasis, we investigated whether activin A could be related to glucometabolic abnormalities in patients with acute myocardial infarction (MI). RESEARCH DESIGN AND METHODS: Activin A measurement and oral glucose tolerance tests (OGTTs) were performed in patients (n = 115) with acute MI, without previously known diabetes, and repeated after 3 months. Release of activin A and potential anti-inflammatory effects of activin A were measured in human endothelial cells. Activin A effects on insulin secretion and inflammation were tested in human pancreatic islet cells. RESULTS: 1) In patients with acute MI, serum levels of activin A were significantly higher in those with abnormal glucose regulation (AGR) compared with those with normal glucose regulation. Activin A levels were associated with the presence of AGR 3 months later (adjusted odds ratio 5.1 [95% CI 1.73-15.17], P = 0.003). 2) In endothelial cells, glucose enhanced the release of activin A, whereas activin A attenuated the release of interleukin (IL)-8 and enhanced the mRNA levels of the antioxidant metallothionein. 3) In islet cells, activin A attenuated the suppressive effect of inflammatory cytokines on insulin release, counteracted the ability of these inflammatory cytokines to induce mRNA expression of IL-8, and induced the expression of transforming growth factor-ß. CONCLUSIONS: We found a significant association between activin A and newly detected AGR in patients with acute MI. Our in vitro findings suggest that this association represents a counteracting mechanism to protect against inflammation, hyperglycemia, and oxidative stress.