Specific inhibition of the transporter MRP4/ABCC4 affects multiple signaling pathways and thrombus formation in human platelets.

The multidrug resistance protein 4 (MRP4) is highly expressed in platelets and several lines of evidence point to an impact on platelet function. MRP4 represents a transporter for cyclic nucleotides as well as for certain lipid mediators. The aim of the present study was to comprehensively characterize the effect of a short-time specific pharmacological inhibition of MRP4 on signaling pathways in platelets. Transport assays in isolated membrane vesicles showed a concentrationdependent inhibition of MRP4-mediated transport of cyclic nucleotides, thromboxane (Tx)B2 and fluorescein (FITC)- labeled sphingosine-1-phosphate (S1P) by the selective MRP4 inhibitor Ceefourin-1. In ex vivo aggregometry studies in human platelets, Ceefourin-1 significantly inhibited platelet aggregation by about 30-50% when ADP or collagen was used as activating agents, respectively. Ceefourin-1 significantly lowered the ADP-induced activation of integrin aIIbb3, indicated by binding of FITC-fibrinogen (about 50% reduction at 50 mM Ceefourin-1), and reduced calcium influx. Furthermore, pre-incubation with Ceefourin-1 significantly increased PGE1- and cinaciguat-induced vasodilatorstimulated phosphoprotein (VASP) phosphorylation, indicating increased cytosolic cAMP as well as cGMP concentrations, respectively. The release of TxB2 from activated human platelets was also attenuated. Finally, selective MRP4 inhibition significantly reduced both the total area covered by thrombi and the average thrombus size by about 40% in a flow chamber model. In conclusion, selective MRP4 inhibition causes reduced platelet adhesion and thrombus formation under flow conditions. This finding is mechanistically supported by inhibition of integrin aIIbb3 activation, elevated VASP phosphorylation and reduced calcium influx, based on inhibited cyclic nucleotide and thromboxane transport as well as possible further mechanisms.

[Use of Tobacco, Alcohol and Illegal Drugs Among Brandenburg Youth 2005-2017]. / Konsum von Tabak, Alkohol und illegalen Substanzen bei Brandenburger Jugendlichen 2005 bis 2017.

BACKGROUND: Children and adolescents are seen as an important target group for reducing tobacco and alcohol consumption in the population. Data on substance use over a longer period of time for adolescents are a basis for addiction policy in the state of Brandenburg and show certain trends. METHODS: Adolescents of the 10th grade in the state of Brandenburg were asked in 2005, 2009, 2013 and 2017 about consumption of alcohol, tobacco and other psychoactive substances and about possibly helpful contact persons. A total of 42,221 adolescents with an average age of 15.7 years (standard deviation 0.7 years) were contacted. RESULTS: Regular (at least weekly) tobacco consumption decreased between 2005 and 2017 from 41 to 17% for girls and from 37 to 18% for boys. The regular consumption of alcohol decreased in girls from 18 to 9% and in boys from 34 to 15%. Boys drink more alcohol than girls. Tobacco use is lowest in high schools and there are differences between regions in the consumption of both substances. The adolescents see their peers as the main contact persons for problems with addictive substances. Professional help is accessed less often. CONCLUSION: The Brandenburg study describes a positive development. If the reduction is sustained or even continued, alcohol and tobacco consumption in the population will decrease. The results suggest strengthening the peer approach for addiction prevention.

[Subnational population health monitoring and reporting: public health at the grassroots level]. / Gesundheitsberichterstattung in Ländern und Kommunen: Public Health an der Basis.

Population health monitoring and reporting provides regular and up-to-date information on health outcomes and its determinants. The outputs of population health monitoring aim to inform policymakers and other stakeholders to develop fact-based decisions. Population health monitoring is located at the national, but also federal state and county level. This paper describes the legal basis for population health monitoring in the federal states' public health acts as well as current challenges and possibilities for further development from a federal state and county perspective on population health monitoring.A legal basis for population health monitoring on the federal state and county level exists for almost all federal states in Germany. The level of detail of these laws varies in terms of responsibility, periodicity of population health monitoring and reporting, content, and designated use. Population health monitoring needs to respond to challenges in the areas of population health monitoring resources, data sources, (intersectoral) reporting, and impact. Practical examples illustrate how the challenges can be handled and further development can take place.Based on its solid legal basis, being a routine task, and its close link to the living conditions of the population, population health monitoring on the federal state and county level has the possibility for cocreating public health at the grassroots level and to be a pioneer for health equity.

The Rickiols: 20-, 22-, and 24-membered Macrolides from the Ascomycete Hypoxylon rickii.

In preceding studies the neotropical ascomycete Hypoxylon rickii turned out to be a prolific source of new secondary metabolites, considering that we had obtained terpenoids with five different scaffolds along with a series of terphenyls. From the mycelial extracts of a 70 L scale fermentation of this strain we additionally isolated nine new macrolides (1-9) by RP-HPLC. The planar structures were elucidated by NMR spectroscopy complemented by HR-ESIMS. The relative configurations were assigned by J-based configuration analyses and confirmed by Kishi's Universal Database. Subsequently, the absolute configurations were assigned by Mosher's method using the shift analysis of a tetra-MTPA derivative. For rickiol A (1) and E (5) we observed transesterification of 20-membered ring structures to 22-membered isomers rickiol A2 (6) and E2 (7), and to 24-membered isomers rickiol A3 (8) and rickiol E3 (9), respectively. Cytotoxic effects and moderate antibiotic activity against Gram-positive bacteria were observed for 1-8 and 1-6 and 8, respectively. The total synthesis of rickiol E3 (9) established easier access to these compounds.

Aspirin Inhibits Platelet-Derived Sphingosine-1-Phosphate Induced Endothelial Cell Migration.

BACKGROUND: Aspirin plays a crucial role in the prevention of cardiovascular diseases. We previously described that aspirin has effects beyond inhibition of platelet aggregation, as it inhibited thrombin-mediated release of sphingosine-1-phosphate (S1P) from human platelets. S1P is a bioactive lipid with important functions on inflammation and apoptosis. In endothelial cells (EC), S1P is a key regulator of cell migration. In this study, we aimed to analyze the effects of aspirin on platelet-induced EC migration. METHODS: Human umbilical EC migration was measured by Boyden chamber assay. EC migration was induced by platelet supernatants of thrombin receptor-activating peptide-1 (AP1) stimulated platelets. To investigate the S1P receptor subtype that promotes EC migration, specific inhibitors of S1P receptor subtypes were applied. RESULTS: S1P induced EC migration in a concentration-dependent manner. EC migration induced by AP1-stimulated platelet supernatants was reduced by aspirin. S1P1 receptor inhibition almost completely abolished EC migration induced by activated platelets. The inhibition of S1P2 or S1P3 receptor had no effect. CONCLUSION: Aspirin inhibits EC migration induced by activated platelets that is in part due to S1P and mediated by the endothelial S1P1 receptor. The clinical significance of this novel mechanism of aspirin action has to be investigated in future studies.

[Local public health reporting as a basis for planning health promotion for children]. / Kommunale Gesundheitsberichterstattung als Planungsgrundlage in der Gesundheitsförderung für Kinder.

The Health Report (Gesundheitsberichterstattung, GBE) describes the health of the overall population and also highlights areas or topics where specific action may be required. Additionally, in line with a new definition, the GBE provides an objective basis for participative processes, thereby building a bridge to health promotion concepts.Municipal integrated health strategies (municipal prevention chains) are based on the salutogenesis concept. One particularly important characteristic of prevention chains is, among others, their participative approach to develop need-based measures on a municipal level. This implies an overarching way of working and a coordinated approach between several stakeholders. Moreover, it requires a combination of health, social, and environmental data, as well as integrated GBE, which serves as a planning basis.In the federal state of Brandenburg, two test regions were chosen, and a municipal prevention chain was followed and monitored by the Health Equity Coordination Office (Koordinierungsstelle Gesundheitliche Chancengleichheit) during the implementation period. In the context of an evaluation, barriers and success factors were identified. During the implementation period four additional phases were identified and specific aspects were also assigned to these phases. Moreover, social environmental oriented data should be reliable, continuously collected, and allow for a local comparability. Data combined from different providers, supplemented with subjective data, could fill the gap and support participative processes.How a good integration in municipal planning processes can be successful, as well as correlated questions about necessary resources, will need to be investigated in future processes.

Synthesis of Antibiotics.

The synthesis of ß-lactams, tetracyclines, and erythromycins as three of the major families of antibiotics will be described herein. We will describe why these antibiotics were the ultimate synthetic targets in the past and how modern synthetic organic chemistry has evolved to address these challenges with new, improved strategies and methods. An additional aspect we would like to highlight here is the fact that these first syntheses had to be particularly creative as most of the modern synthetic methods were not available at that time, or were developed in the course of these syntheses.

Sphingosine-1-Phosphate and Its Receptors: A Mutual Link between Blood Coagulation and Inflammation.

Sphingosine-1-phosphate (S1P) is a versatile lipid signaling molecule and key regulator in vascular inflammation. S1P is secreted by platelets, monocytes, and vascular endothelial and smooth muscle cells. It binds specifically to a family of G-protein-coupled receptors, S1P receptors 1 to 5, resulting in downstream signaling and numerous cellular effects. S1P modulates cell proliferation and migration, and mediates proinflammatory responses and apoptosis. In the vascular barrier, S1P regulates permeability and endothelial reactions and recruitment of monocytes and may modulate atherosclerosis. Only recently has S1P emerged as a critical mediator which directly links the coagulation factor system to vascular inflammation. The multifunctional proteases thrombin and FXa regulate local S1P availability and interact with S1P signaling at multiple levels in various vascular cell types. Differential expression patterns and intracellular signaling pathways of each receptor enable S1P to exert its widespread functions. Although a vast amount of information is available about the functions of S1P and its receptors in the regulation of physiological and pathophysiological conditions, S1P-mediated mechanisms in the vasculature remain to be elucidated. This review summarizes recent findings regarding the role of S1P and its receptors in vascular wall and blood cells, which link the coagulation system to inflammatory responses in the vasculature.

Ruthenium-nitrosyl complexes with glycine, L-alanine, L-valine, L-proline, D-proline, L-serine, L-threonine, and L-tyrosine: synthesis, X-ray diffraction structures, spectroscopic and electrochemical properties, and antiproliferative activity.

The reactions of [Ru(NO)Cl5](2-) with glycine (Gly), L-alanine (L-Ala), L-valine (L-Val), L-proline (L-Pro), D-proline (D-Pro), L-serine (L-Ser), L-threonine (L-Thr), and L-tyrosine (L-Tyr) in n-butanol or n-propanol afforded eight new complexes (1-8) of the general formula [RuCl3(AA-H)(NO)](-), where AA = Gly, L-Ala, L-Val, L-Pro, D-Pro, L-Ser, L-Thr, and L-Tyr, respectively. The compounds were characterized by elemental analysis, electrospray ionization mass spectrometry (ESI-MS), (1)H NMR, UV-visible and ATR IR spectroscopy, cyclic voltammetry, and X-ray crystallography. X-ray crystallography studies have revealed that in all cases the same isomer type (from three theoretically possible) was isolated, namely mer(Cl),trans(NO,O)-[RuCl3(AA-H)(NO)], as was also recently reported for osmium analogues with Gly, L-Pro, and D-Pro (see Z. Anorg. Allg. Chem. 2013, 639, 1590-1597). Compounds 1, 4, 5, and 8 were investigated by ESI-MS with regard to their stability in aqueous solution and reactivity toward sodium ascorbate. In addition, cell culture experiments in three human cancer cell lines, namely, A549 (nonsmall cell lung carcinoma), CH1 (ovarian carcinoma), and SW480 (colon carcinoma), were performed, and the results are discussed in conjunction with the lipophilicity of compounds.

Association between MGMT Enhancer Methylation and MGMT Promoter Methylation, MGMT Protein Expression, and Overall Survival in Glioblastoma.

The repair protein O6-methylguanine-DNA methyltransferase (MGMT) is regulated epigenetically, mainly by the methylation of the MGMT promoter. MGMT promoter methylation status has emerged as a prognostic and predictive biomarker for patients with newly diagnosed glioblastoma (GBM). However, a strong negative correlation between MGMT promoter methylation and MGMT protein expression cannot be applied as a rule for all GBM patients. In order to investigate if the DNA methylation status of MGMT enhancers is associated with MGMT promoter methylation, MGMT expression, and the overall survival (OS) of GBM patients, we established assays based on high-resolution melting analysis and pyrosequencing for one intragenic and three intergenic MGMT enhancers. For CpGs in an enhancer located 560 kb upstream of the MGMT promoter, we found a significant negative correlation between the methylation status and MGMT protein levels of GBM samples expressing MGMT. The methylation status of CpGs in the intragenic enhancer (hs696) was strongly negatively correlated with MGMT promoter methylation and was significantly higher in MGMT-expressing GBM samples than in MGMT-non-expressing GBM samples. Moreover, low methylation of CpGs 01-03 and CpGs 09-13 was associated with the longer OS of the GBM patients. Our findings indicate an association between MGMT enhancer methylation and MGMT promoter methylation, MGMT protein expression, and/or OS.

Coaching as a growth- or security-oriented process-How regulatory fit increases coaching success.

Regulatory focus theory suggests that promoters are more concerned with growth and preventers are more concerned with security. Since coaching is a growth-oriented process, it seems to be more suitable for clients high on promotion than for clients high on prevention. Applying regulatory fit theory, the present research investigates how preventers can also benefit from coaching. First, a study looking at real coaching processes (N1 = 103) found that a higher promotion than prevention focus was indeed related to more coaching success, i.e., satisfaction and approach motivation. Next, testing the hypothesis that fit effects should also be present in coaching, a study using a vignette approach (N2 = 99) shows that participants experiencing a fit between their focus and a promotion versus a prevention coaching indicate a better coaching evaluation than participants experiencing no fit. In three studies (N3a = 120, N3b = 85, N3c = 189), we used an experimental approach and manipulated the regulatory focus of coaching interventions. We found promotion as well as prevention fit effects showing that participants experiencing a fit indicate more coaching success than participants experiencing no fit. Two studies (N4a = 41, N4b = 87) further tested interpersonal fit, i.e., the fit between the coach's and client's regulatory focus. We found promotion as well as prevention fit effects on participants' satisfaction with and trust in a coach (Study 4a) and promotion fit effects on participants' goal attainment and coaching progress (4b). The findings suggest that by adapting coaching to the client's focus, coaching success can be increased not only for promoters but also for preventers. Thus, we found that regulatory fit effects, albeit small to medium, are also present in coaching. Multiple studies assessing multiple variables relevant to coaching showed that the findings differ regarding the interventions used and the variables that we looked at. The practical implications of these findings are discussed.

Regulation of human vascular protease-activated receptor-3 through mRNA stabilization and the transcription factor nuclear factor of activated T cells (NFAT).

Thrombin promotes vascular smooth muscle cell (SMC) proliferation and inflammation via protease-activated receptor (PAR)-1. A further thrombin receptor, PAR-3, acts as a PAR-1 cofactor in some cell-types. Unlike PAR-1, PAR-3 is dynamically regulated at the mRNA level in thrombin-stimulated SMC. This study investigated the mechanisms controlling PAR-3 expression. In human vascular SMC, PAR-3 siRNA attenuated thrombin-stimulated interleukin-6 expression and extracellular signal-regulated kinases 1/2 phosphorylation, indicating PAR-3 contributes to net thrombin responses in these cells. Thrombin slowed the decay of PAR-3 but not PAR-1 mRNA in the presence of actinomycin D and induced cytosolic shuttling and PAR-3 mRNA binding of the mRNA-stabilizing protein human antigen R (HuR). HuR siRNA prevented thrombin-induced PAR-3 expression. By contrast, forskolin inhibited HuR shuttling and destabilized PAR-3 mRNA, thus reducing PAR-3 mRNA and protein expression. Other cAMP-elevating agents, including the prostacyclin-mimetic iloprost, also down-regulated PAR-3, accompanied by decreased HuR/PAR-3 mRNA binding. Iloprost-induced suppression of PAR-3 was reversed with a myristoylated inhibitor of protein kinase A and mimicked by phorbol ester, an inducer of cyclooxygenase-2. In separate studies, iloprost attenuated PAR-3 promoter activity and prevented binding of nuclear factor of activated T cells (NFAT2) to the human PAR-3 promoter in a chromatin immunoprecipitation assay. Accordingly, PAR-3 expression was suppressed by the NFAT inhibitor cyclosporine A or NFAT2 siRNA. Thus human PAR-3, unlike PAR-1, is regulated post-transcriptionally via the mRNA-stabilizing factor HuR, whereas transcriptional control involves NFAT2. Through modulation of PAR-3 expression, prostacyclin and NFAT inhibitors may limit proliferative and inflammatory responses to thrombin after vessel injury.

Regulation of functionally active P2Y12 ADP receptors by thrombin in human smooth muscle cells and the presence of P2Y12 in carotid artery lesions.

OBJECTIVE: The platelet P2Y12 ADP receptor is a well-known target of thienopyridine-type antiplatelet drugs. This study is the first to describe increased transcriptional expression of a functionally active P2Y12 in response to thrombin in human vascular smooth muscle cells (SMC). METHODS AND RESULTS: On exposure to thrombin, P2Y12 mRNA was transiently increased, whereas total protein and cell surface expression of P2Y12 were markedly increased within 6 hours and remained elevated over 24 hours. This effect was mediated by activation of nuclear factor κB. Preincubation with thrombin significantly enhanced the efficacy of the P2Y receptor agonist 2-methylthio-ADP to induce interleukin 6 expression and SMC mitogenesis. Effects induced by 2-methylthio-ADP were prevented by RNA interference-mediated knockdown of P2Y12 and a selective P2Y12-antagonist R-138727, the active metabolite of prasugrel. In addition, positive P2Y12 immunostaining was shown in SMC of human carotid artery plaques and was found to colocalize with tissue factor, the rate-limiting factor of thrombin formation in vivo. CONCLUSIONS: These data suggest that the P2Y12 receptor not only is central to ADP-induced platelet activation but also may mediate platelet-independent responses, specifically under conditions of enhanced thrombin formation, such as local vessel injury and atherosclerotic plaque rupture.

Platelet apelin receptor expression is reduced in patients with acute myocardial infarction.

BACKGROUND: The G-protein-coupled apelin receptor and its apelin ligand are an emerging regulatory system of the vascular homeostasis. To date, the implications of the apelin/apelin receptor system in athero-thrombosis are not completely clarified yet. This study determines the expression of the apelin receptor on human platelets, the effect of different apelin isoforms on platelet aggregation and the potential role of the apelin/apelin receptor system in acute myocardial infarction. METHODS: We applied immunofluorescence staining, Western Blot analysis, aggregometry, and flow cytometry to elucidate the role of the apelin receptor in activated platelets. Furthermore, in an observational pilot study, we assessed platelet apelin recpetor expression and apelin-17 plasma levels in patients with acute myocardial infarction (AMI, n = 27). RESULTS: Immunofluorescence staining indicates that the apelin receptor is located at the cell membrane in resting platelets and diminishes upon activation with a selective thrombin receptor-activating peptide (AP1, 3 to 100 µM). Western Blot analyses of AP1-activated platelets and their supernatants suggest that the apelin receptor is not predominantly internalized but is released from activated platelets. The isoform apelin-17 attenuated AP-1-induced platelet activation in-vitro, presumably via a NO-dependent mechanism. Furthermore, platelet apelin receptor expression was significantly reduced in patients with AMI (n = 27) compared to age-matched controls (n = 14; p < 0.05) and inversely correlated with troponin I plasma levels (r = -0.46; p = 0.03). Besides that, circulating apelin-17 was significantly reduced in MI patients compared to the control group. CONCLUSION: Taken together, our data support a crucial role of the platelet apelinergic system assuming an antithrombotic effect and therefore holding a potential diagnostic and therapeutic impact.

Spectroscopic study on the communication between a heme a3 propionate, Asp399 and the binuclear center of cytochrome c oxidase from Paracoccus denitrificans.

The proton pumping mechanism of cytochrome c oxidase on a molecular level is highly disputed. Recently theoretical calculations and real time electron transfer measurements indicated the involvement of residues in the vicinity of the ring A propionate of heme a3, including Asp399 and the CuB ligands His 325, 326. In this study we probed the interaction of Asp399 with the binuclear center and characterize the protonation state of its side chain. Redox induced FTIR difference spectra of mutations at the site in direct comparison to wild type, indicate that below pH 5 Asp 399 displays signals typical for the deprotonation of the acidic residue with reduction of the enzyme. Interestingly at a pH higher than 5, no contributions from Asp 399 are evident. In order to probe the interaction of the site with the binuclear center we followed the rebinding of CO by infrared spectroscopy for mutations on residue Asp399 to Glu, Asn and Leu. Previously different CO conformers have been identified for bacterial cytochrome c oxidases, and its pH dependent behaviour discussed to be relevant for catalysis. Interestingly we observe the lack of this pH dependency and a strong influence on the observable conformers for all mutants studied here, clearly suggesting a communication of the site with the heme-copper center and the nearby histidine residues.

Immune system-mediated atherosclerosis caused by deficiency of long non-coding RNA MALAT1 in ApoE-/-mice.

Aims: The immune system is considered a key driver of atherosclerosis, and beyond proteins and microRNAs (miRs), long non-coding RNAs (lncRNAs) are implicated in immune control. We previously described that lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is involved in cardiac innate immunity in a myocarditis model. Here, we investigated the impact of MALAT1 deficiency upon atherosclerosis development. Methods and results: Heterozygous MALAT1-deficient ApoE-/- mice displayed massive immune system dysregulation and atherosclerosis within 2 months even when kept on normal diet. Aortic plaque area (P < 0.05) and aortic root plaque size (P < 0.001) were increased in MALAT1-deficient vs. MALAT1-wildtype ApoE-/- mice. Serum levels of interferon-γ (IFN-γ), tumour necrosis factor (TNF), and interleukin 6 (IL6) were elevated (P < 0.001) in MALAT1-deficient animals. MALAT1-deficient bone marrow-derived macrophages showed enhanced expression of TNF (P = 0.001) and inducible NO synthase (NOS2) (P = 0.002), suppressed MMP9 (P < 0.001), and impaired phagocytic activity (P < 0.001) upon lipopolysaccharide stimulation. RNA-sequencing revealed grossly altered transcriptomes of MALAT1-deficient splenocytes already at baseline, with massive induction of IFN- γ, TNF, NOS2, and granzyme B; CC and CXC chemokines and CCR8; and innate immunity genes interferon-induced protein with tetratricopeptide repeats (IFIT)1/3, interferon-induced transmembrane protein (IFITM)1/3, ISG15. Multiple miRs were up to 45-fold upregulated. Further, selective ablation of the cytosolic part of the MALAT1 system only, the enzymatically MALAT1-derived mascRNA, resulted in massive induction of TNF (P = 0.004) and IL6 (P = 0.028) in macrophages. Northern analysis of post-myocardial infarction patient vs. control peripheral blood mononuclear cells showed reduced (P = 0.005) mascRNA in the patients. CHART-enriched RNA-sequencing reads at the genomic loci of MALAT1 and neighbouring nuclear enriched abundant transcript (NEAT1) documented direct interaction between these lncRNA transcripts. Conclusion: The data suggest a molecular circuit involving the MALAT1-mascRNA system, interactions between MALAT1 and NEAT1, and key immune effector molecules, cumulatively impacting upon the development of atherosclerosis. It appears reasonable to look for therapeutic targets in this circuit and to screen for anomalies in the NEAT1-MALAT1 region in humans, too, as possible novel disease risk factors.

Release of Platelet-Derived Sphingosine-1-Phosphate Involves Multidrug Resistance Protein 4 (MRP4/ABCC4) and Is Inhibited by Statins.

Sphingosine-1-phosphate (S1P) is a potent lipid mediator released from activated platelets by an adenosine triphosphate (ATP)-dependent export mechanism. A candidate transport protein is the multidrug resistance protein 4 (MRP4/ABCC4), an ATP-dependent transporter highly expressed in platelets. Furthermore, several statins are known to affect platelet functions and exhibit antithrombotic properties. This study determines the involvement of MRP4 in the transport of S1P and a possible interference by statins. Transport studies in membrane vesicles of Sf9 cells containing recombinant human MRP4 revealed that MRP4 mediates ATP-dependent transport of fluorescein- and tritium-labelled S1P. Also, ATP-dependent S1P transport in platelet membrane vesicles containing endogenous MRP4 was inhibited by the MRP inhibitor MK571 and the MRP4-selective compound Ceefourin-1. Confocal microscopy using fluorescein-labelled S1P as well as boron-dipyrromethene (BODIPY)-labelled sphingosine indicated association of S1P and MRP4 in human platelets. In MRP4-deficient mice, agonist-induced S1P secretion was reduced compared with matched wild-type C57Bl/6 mice and platelet S1P concentrations were lower. Fluvastatin and rosuvastatin interfered with MRP4 function inhibiting ATP-dependent cGMP (cyclic guanosine monophosphate) uptake into MRP4-containing vesicles, inhibited MRP4-mediated S1P transport in vitro and significantly attenuated endogenous S1P release from agonist-activated platelet ex vivo. These data suggest that release of S1P from platelets depends on MRP4 and statins can interfere with this transport process. Potentially, this may be relevant for the pleiotropic anti-inflammatory effects of statins and their effect on modulating atherothrombosis.

Platelet activation parameters and platelet-leucocyte-conjugate formation in glioblastoma multiforme patients.

Patients with glioblastoma multiforme (GBM) suffer from an increased incidence of vascular thrombotic events. However, key influencing factors of the primary hemostasis have not been characterized in GBM patients to date. Thus, the present study determines the activation level of circulating platelets in GBM patients, in-vitro reactivity to agonist-induced platelet stimulation and the formation of circulating platelet-leucocyte conjugates as well as the plasma levels of the proinflammatory lipid mediator sphingosine-1-phosphate (S1P). The endogenous thrombin potential (ETP) was determined as global marker for hemostasis. The 21 GBM patients and 21 gender and age matched healthy individuals enrolled in this study did not differ in mean total platelet count. Basal surface expression of platelet CD63 determined by flow cytometry was significantly increased in GBM patients compared to controls as was observed for the concentration of soluble P-selectin in the plasma of GBM patients. While the ETP was not affected, the immunomodulatory lipid S1P was significantly decreased in peripheral blood in GBM. Interestingly, monocyte expression of PSGL-1 (CD162) was decreased in GBM patient blood, possibly explaining the rather decreased formation of platelet-monocyte conjugates. Our study reveals an increased CD63 expression and P-selectin expression/ secretion of circulating platelets in GBM patients. In parallel a down-modulated PSGL-1 expression in circulating monocytes and a trend towards a decreased formation of heterotypic platelet-monocyte conjugates in GBM patients was seen. Whether this and the observed decreased plasma level of the immunomodulatory S1P reflects a systemic anti-inflammatory status needs to be addressed in future studies.

Expression of S1P metabolizing enzymes and receptors correlate with survival time and regulate cell migration in glioblastoma multiforme.

A signaling molecule which is involved in proliferation and migration of malignant cells is the lipid mediator sphingosine-1-phosphate (S1P). There are hints for a potential role of S1P signaling in malignant brain tumors such as glioblastoma multiforme (GBM) which is characterized by a poor prognosis. Therefore, a comprehensive expression analysis of S1P receptors (S1P1-S1P5) and S1P metabolizing enzymes in human GBM (n = 117) compared to healthy brain (n = 10) was performed to evaluate their role for patient´s survival. Furthermore, influence of S1P receptor inhibition on proliferation and migration were studied in LN18 GBM cells. Compared to control brain, mRNA levels of S1P1, S1P2, S1P3 and S1P generating sphingosine kinase-1 were elevated in GBM. Kaplan-Meier analyses demonstrated an association between S1P1 and S1P2 with patient´s survival times. In vitro, an inhibitory effect of the SphK inhibitor SKI-II on viability of LN18 cells was shown. S1P itself had no effect on viability but stimulated LN18 migration which was blocked by inhibition of S1P1 and S1P2. The participation of S1P1 and S1P2 in LN18 migration was further supported by siRNA-mediated silencing of these receptors. Immunoblots and inhibition experiments suggest an involvement of the PI3-kinase/AKT1 pathway in the chemotactic effect of S1P in LN18 cells.In summary, our data argue for a role of S1P signaling in proliferation and migration of GBM cells. Individual components of the S1P pathway represent prognostic factors for patients with GBM. Perspectively, a selective modulation of S1P receptor subtypes could represent a therapeutic approach for GBM patients and requires further evaluation.

Measurement of the intraocular pressure with the "transpalpebral tonometer" TGDc-01 in comparison with applanation tonometry.

BACKGROUND: An irregular corneal surface compromises IOP measurement by Goldmann applanation tonometry. In such cases accurate measurement without corneal contact would be desirable. The new eyelid tonometer TGDc-01 measures IOP without corneal contact through the eyelid. The aim of the study was to evaluate the accuracy of the eyelid tonometer compared with Goldmann applanation tonometry (cornea thickness-corrected values) in subjects without corneal alterations. METHODS: IOP was measured in 199 eyes of 103 subjects without corneal alterations by means of two different methods. Measurements with the transpalpebral tonometer TGDc-01 and the Goldmann applanation tonometer were performed within 5 min in random order. RESULTS: The mean difference between lid tonometry and Goldmann applanation tonometry was 0.71 mmHg, SD +/-2.467 mmHg. In the reliability analysis the intraclass correlation coefficient was 0.8620. Compared with Goldmann applanation tonometry 66.4% of the IOP readings measured by lid tonometry were in an interval of +/-2 mmHg, 81.0% in an interval of +/-3 mmHg. The maximum of deviation was -6 mmHg and +6 mmHg, respectively. The Bland and Altman plots are shown. CONCLUSIONS: Lid tonometry correlates sufficiently with Goldmann applanation tonometry, but in more than 10% of the measurements the IOP readings differed by more than 3 mmHg. The eyelid tonometer may be helpful as a screening tool when Goldmann applanation tonometry is not applicable.