[Systematic Reviews on the Effectiveness of Multidisciplinary Rehabilitation]. / Systematische Reviews zur Wirksamkeit der multidisziplinären Rehabilitation.

Systematic reviews and meta-analyses of clinical trials are considered to represent the highest level of scientific evidence in clinical medicine provided internationally accepted guidelines and checklists are followed.In systematic reviews and meta-analyses all clinical studies focussing a specific predefined clinical question are collected and evaluated. The results of systematic reviews strongly depend on the study protocol, including the exact definition of the population of interest, the therapeutic intervention under consideration and, last not least, the time period of observation. Moreover, evaluating multidisciplinary rehabilitation, its specifications with regard to therapeutic content, intensity and duration, supervision and general framework must be considered for correctly estimating determinants that control therapeutic success or failure.The range of potential risks of bias arising during planning, realization and publication of clinical studies is considerable and needs to be carefully estimated with regard to each single study included in meta-analysis.Taking together, the incremental scientific value of systematic reviews and meta-analyses cannot be taken for granted, but strongly depends on the methodological quality of the clinical studies being included as well as on the systematic process of the meta-analysis and the critical interpretation of the results.

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.

Platelet-Derived S1P and Its Relevance for the Communication with Immune Cells in Multiple Human Diseases.

Sphingosine-1-phosphate (S1P) is a versatile signaling lipid involved in the regulation of numerous cellular processes. S1P regulates cellular proliferation, migration, and apoptosis as well as the function of immune cells. S1P is generated from sphingosine (Sph), which derives from the ceramide metabolism. In particular, high concentrations of S1P are present in the blood. This originates mainly from erythrocytes, endothelial cells (ECs), and platelets. While erythrocytes function as a storage pool for circulating S1P, platelets can rapidly generate S1P de novo, store it in large quantities, and release it when the platelet is activated. Platelets can thus provide S1P in a short time when needed or in the case of an injury with subsequent platelet activation and thereby regulate local cellular responses. In addition, platelet-dependently generated and released S1P may also influence long-term immune cell functions in various disease processes, such as inflammation-driven vascular diseases. In this review, the metabolism and release of platelet S1P are presented, and the autocrine versus paracrine functions of platelet-derived S1P and its relevance in various disease processes are discussed. New pharmacological approaches that target the auto- or paracrine effects of S1P may be therapeutically helpful in the future for pathological processes involving S1P.

PIM1 Inhibition Affects Glioblastoma Stem Cell Behavior and Kills Glioblastoma Stem-like Cells.

Despite comprehensive therapy and extensive research, glioblastoma (GBM) still represents the most aggressive brain tumor in adults. Glioma stem cells (GSCs) are thought to play a major role in tumor progression and resistance of GBM cells to radiochemotherapy. The PIM1 kinase has become a focus in cancer research. We have previously demonstrated that PIM1 is involved in survival of GBM cells and in GBM growth in a mouse model. However, little is known about the importance of PIM1 in cancer stem cells. Here, we report on the role of PIM1 in GBM stem cell behavior and killing. PIM1 inhibition negatively regulates the protein expression of the stem cell markers CD133 and Nestin in GBM cells (LN-18, U-87 MG). In contrast, CD44 and the astrocytic differentiation marker GFAP were up-regulated. Furthermore, PIM1 expression was increased in neurospheres as a model of GBM stem-like cells. Treatment of neurospheres with PIM1 inhibitors (TCS PIM1-1, Quercetagetin, and LY294002) diminished the cell viability associated with reduced DNA synthesis rate, increased caspase 3 activity, decreased PCNA protein expression, and reduced neurosphere formation. Our results indicate that PIM1 affects the glioblastoma stem cell behavior, and its inhibition kills glioblastoma stem-like cells, pointing to PIM1 targeting as a potential anti-glioblastoma therapy.

GD2 targeting by dinutuximab beta is a promising immunotherapeutic approach against malignant glioma.

PURPOSE: Disialoganglioside GD2 is expressed by glioblastoma multiforme (GBM) cells representing a promising target for anti-GD2 immunotherapeutic approaches. The aim of the present study was to investigate anti-tumor efficacy of the chimeric anti-GD2 antibody (Ab) dinutuximab beta against GBM. METHODS: Expression levels of GD2 and complement regulatory proteins (CRP; CD46, CD55 and CD59) on well-known and newly established primary tumor originated GBM cell lines were analyzed by flow cytometry. Ab-dependent cellular (ADCC) and complement-dependent cytotoxicity (CDC) mediated by dinutuximab beta against GBM cells were determined by a non-radioactive calcein-AM-based assay. RESULTS: Analysis of primary GBM cells revealed a heterogeneous GD2 expression that varied between the cell lines analyzed with higher expression levels in the tumor surface compared to the core originated cells. Both GD2-positive and -negative tumor cells were detected in every cell line analyzed. In contrast to CDC, ADCC mediated by dinutuximab beta was observed against the majority of GBM cells. Importantly, CDC-resistant cells showed high expression of the CRP CD46, CD55 and CD59. CONCLUSION: Our present data show anti-tumor effects mediated by dinutuximab beta against GBM cells providing a rationale for a GD2-directed immunotherapy against GBM. Due to high CRP expression, a combining of GD2-targeting with CRP blockade might be a further treatment option for GBM.

Reevaluation of risk factors for time to subsequent events after first stroke occurrence using a new weighted all-cause effect measure.

BACKGROUND: Risk diseases and risk factors for stroke include atrial fibrillation, hypertension, diabetes mellitus, smoking, and elevated LDL-cholesterol. Due to modern treatment options, the impact of these risk diseases on subsequent cardiovascular events or death after a first stroke is less clear and needs to be elucidated. We therefore aimed to get insights into the persistence of adverse prognostic effects of these risk diseases and risk factors on subsequent stroke or death events 1 year after the first stroke by using the new weighted all-cause hazard ratio. METHODS: This study evaluates the 1 year follow-up of 470 first ever stroke cases identified in the area of Ludwigshafen, Germany, with 23 deaths and 34 subsequent stroke events. For this purpose, the recently introduced "weighted all-cause hazard ratio" was used, which allows a weighting of the competing endpoints within a composite endpoint. Moreover, we extended this approach to allow an adjustment for covariates. RESULTS: None of these risk factors and risk diseases, most probably being treated after the first stroke, remained to be associated with a subsequent death or stroke [weighted hazard ratios (95% confidence interval) for diabetes mellitus, atrial fibrillation, high cholesterol, hypertension, and smoking are 0.4 (0.2-0.9), 0.8 (0.4-2.2), 1.3 (0.5-2.5), 1.2 (0.3-2.7), 1.6 (0.8-3.6), respectively]. However, when analyzed separately in terms of death and stroke, the risk factors and risk diseases under investigation affect the subsequent event rate to a variable degree. CONCLUSIONS: Using the new weighted hazard ratio, established risk factors and risk diseases for the occurrence of a first stroke do not remain to be significant predictors for subsequent events like death or recurrent stroke. It has been demonstrated that the new weighted hazard ratio can be used for a more adequate analysis of cardiovascular risk and disease progress. The results have to be confirmed within a larger study with more events.

Protease-activated receptor 2 deficiency mediates cardiac fibrosis and diastolic dysfunction.

AIMS: Heart failure with preserved ejection fraction (HFpEF) and pathological cardiac aging share a complex pathophysiology, including extracellular matrix remodelling (EMR). Protease-activated receptor 2 (PAR2) deficiency is associated with EMR. The roles of PAR1 and PAR2 have not been studied in HFpEF, age-dependent cardiac fibrosis, or diastolic dysfunction (DD). METHODS AND RESULTS: Evaluation of endomyocardial biopsies from patients with HFpEF (n = 14) revealed that a reduced cardiac PAR2 expression was associated with aggravated DD and increased myocardial fibrosis (r = -0.7336, P = 0.0028). In line, 1-year-old PAR2-knockout (PAR2ko) mice suffered from DD with preserved systolic function, associated with an increased age-dependent α-smooth muscle actin expression, collagen deposition (1.7-fold increase, P = 0.0003), lysyl oxidase activity, collagen cross-linking (2.2-fold increase, P = 0.0008), endothelial activation, and inflammation. In the absence of PAR2, the receptor-regulating protein caveolin-1 was down-regulated, contributing to an augmented profibrotic PAR1 and transforming growth factor beta (TGF-ß)-dependent signalling. This enhanced TGF-ß/PAR1 signalling caused N-proteinase (ADAMTS3) and C-proteinase (BMP1)-related increased collagen I production from cardiac fibroblasts (CFs). PAR2 overexpression in PAR2ko CFs reversed these effects. The treatment with the PAR1 antagonist, vorapaxar, reduced cardiac fibrosis by 44% (P = 0.03) and reduced inflammation in a metabolic disease model (apolipoprotein E-ko mice). Patients with HFpEF with upstream PAR inhibition via FXa inhibitors (n = 40) also exhibited reduced circulating markers of fibrosis and DD compared with patients treated with vitamin K antagonists (n = 20). CONCLUSIONS: Protease-activated receptor 2 is an important regulator of profibrotic PAR1 and TGF-ß signalling in the heart. Modulation of the FXa/FIIa-PAR1/PAR2/TGF-ß-axis might be a promising therapeutic approach to reduce HFpEF.

Hirudins of the Asian medicinal leech, Hirudinaria manillensis: same same, but different.

Blood coagulation in vertebrates is a complex mechanism that involves the precisely coordinated and regulated action of a cascade of factors in order to prevent excessive blood loss upon wounding. Any blood sucking ectoparasite, however, has to circumvent this mechanism to ensure the uptake of an adequate blood meal. Inhibitors of blood coagulation in the saliva are hence widespread among these animals. Thrombin as a key factor of blood coagulation is a prominent target of such inhibitors, and hirudin is probably the best known among the thrombin inhibitors. Hirudin was originally described in the genus Hirudo, but occurs in other leech genera like Hirudinaria and Macrobdella as well. Besides several isoforms of hirudin, a new class of putative leech saliva components, the hirudin-like factors (HLFs), was identified in both genera Hirudo and Hirudinaria. Here, we describe the expression, purification, and functional characterization of three HLFs (HLF5, 6, and 8, respectively) and two additional hirudins (HM3 and HM4) of Hirudinaria manillensis. While HLF6 lacked any inhibitory activity on thrombin, HLF5 as well as HLF8 clearly exhibited anticoagulatory properties. The inhibitory activity of HLF5 and HLF8, however, was much lower compared with both HM3 and HM4 of Hirudinaria manillensis as well as the hirudin variants 1 (HV1) and 2 (HV2) of Hirudo medicinalis. Neither an inhibition of trypsin nor a platelet aggregation was caused by HLF8. Our data indicates the presence of two classes (rather than isoforms) of hirudins in Hirudinaria manillensis with markedly different inhibitory activity on human thrombin.

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.

Signaling Crosstalk of TGF-ß/ALK5 and PAR2/PAR1: A Complex Regulatory Network Controlling Fibrosis and Cancer.

Both signaling by transforming growth factor-ß (TGF-ß) and agonists of the G Protein-coupled receptors proteinase-activated receptor-1 (PAR1) and -2 (PAR2) have been linked to tissue fibrosis and cancer. Intriguingly, TGF-ß and PAR signaling either converge on the regulation of certain matrix genes overexpressed in these pathologies or display mutual regulation of their signaling components, which is mediated in part through sphingosine kinases and sphingosine-1-phosphate and indicative of an intimate signaling crosstalk between the two pathways. In the first part of this review, we summarize the various regulatory interactions that have been discovered so far according to the organ/tissue in which they were described. In the second part, we highlight the types of signaling crosstalk between TGF-ß on the one hand and PAR2/PAR1 on the other hand. Both ligand⁻receptor systems interact at various levels and by several mechanisms including mutual regulation of ligand⁻ligand, ligand⁻receptor, and receptor⁻receptor at the transcriptional, post-transcriptional, and receptor transactivation levels. These mutual interactions between PAR2/PAR1 and TGF-ß signaling components eventually result in feed-forward loops/vicious cycles of matrix deposition and malignant traits that exacerbate fibrosis and oncogenesis, respectively. Given the crucial role of PAR2 and PAR1 in controlling TGF-ß receptor activation, signaling, TGF-ß synthesis and bioactivation, combining PAR inhibitors with TGF-ß blocking agents may turn out to be more efficient than targeting TGF-ß alone in alleviating unwanted TGF-ß-dependent responses but retaining the beneficial ones.

Transforming Growth Factor-ß1/Activin Receptor-like Kinase 5-Mediated Cell Migration is Dependent on the Protein Proteinase-Activated Receptor 2 but not on Proteinase-Activated Receptor 2-Stimulated Gq-Calcium Signaling.

Transforming growth factor-ß (TGF-ß), serine proteinases such as trypsin, and proteinase-activated receptor 2 (PAR2) promote tumor development by stimulating invasion and metastasis. Previously, we found that in cancer cells derived from pancreatic ductal adenocarcinoma (PDAC) PAR2 protein is necessary for TGF-ß1-dependent cell motility. Here, we show in the same cells that, conversely, the type I TGF-ß receptor activin receptor-like kinase 5 is dispensable for trypsin and PAR2 activating peptide (PAR2-AP)-induced migration. To reveal whether Gq-calcium signaling is a prerequisite for PAR2 to enhance TGF-ß signaling, we investigated the effects of PAR2-APs, PAR2 mutation and PAR2 inhibitors on TGF-ß1-induced migration, reporter gene activity, and Smad activation. Stimulation of cells with PAR2-AP alone failed to enhance basal or TGF-ß1-induced C-terminal phosphorylation of Smad3, Smad-dependent activity of a luciferase reporter gene, and cell migration. Consistently, in complementary loss of function studies, abrogation of the PAR2-Gq-calcium signaling arm failed to suppress TGF-ß1-induced cell migration, reporter gene activity, and Smad3 activation. Together, our findings suggest that the calcium-regulating motif is not required for PAR2 to synergize with TGF-ß1 to promote cell motility. Additional experiments in PDAC cells revealed that PAR2 and TGF-ß1 synergy may involve TGF-ß1 induction of enzymes that cause autocrine cleavage/activation of PAR2, possibly through a biased signaling function. Our results suggest that although reducing PAR2 protein expression may potentially block TGF-ß's prooncogenic function, inhibiting PAR2-Gq-calcium signaling alone would not be sufficient to achieve this effect.

Sphingosine 1-phosphate (S1P) signaling in glioblastoma multiforme-A systematic review.

The multifunctional sphingosine-1-phosphate (S1P) is a lipid signaling molecule and central regulator in the development of several cancer types. In recent years, intriguing information has become available regarding the role of S1P in the progression of Glioblastoma multiforme (GBM), the most aggressive and common brain tumor in adults. S1P modulates numerous cellular processes in GBM, such as oncogenesis, proliferation and survival, invasion, migration, metastasis and stem cell behavior. These processes are regulated via a family of five G-protein-coupled S1P receptors (S1PR1-5) and may involve mainly unknown intracellular targets. Distinct expression patterns and multiple intracellular signaling pathways of each S1PR subtype enable S1P to exert its pleiotropic cellular actions. Several studies have demonstrated alterations in S1P levels, the involvement of S1PRs and S1P metabolizing enzymes in GBM pathophysiology. While the tumorigenic actions of S1P involve the activation of several kinases and transcription factors, the specific G-protein (Gi, Gq, and G12/13)-coupled signaling pathways and downstream mediated effects in GBM remain to be elucidated in detail. This review summarizes the recent findings concerning the role of S1P and its receptors in GBM. We further highlight the current insights into the signaling pathways considered fundamental for regulating the cellular processes in GMB and ultimately patient prognosis.

Proteinase-Activated Receptor 2 May Drive Cancer Progression by Facilitating TGF-ß Signaling.

The G protein-coupled receptor proteinase-activated receptor 2 (PAR2) has been implicated in various aspects of cellular physiology including inflammation, obesity and cancer. In cancer, it usually acts as a driver of cancer progression in various tumor types by promoting invasion and metastasis in response to activation by serine proteinases. Recently, we discovered another mode through which PAR2 may enhance tumorigenesis: crosstalk with transforming growth factor-ß (TGF-ß) signaling to promote TGF-ß1-induced cell migration/invasion and invasion-associated gene expression in ductal pancreatic adenocarcinoma (PDAC) cells. In this chapter, we review what is known about the cellular TGF-ß responses and signaling pathways affected by PAR2 expression, the signaling activities of PAR2 required for promoting TGF-ß signaling, and the potential molecular mechanism(s) that underlie(s) the TGF-ß signaling-promoting effect. Since PAR2 is activated through various serine proteinases and biased agonists, it may couple TGF-ß signaling to a diverse range of other physiological processes that may or may not predispose cells to cancer development such as local inflammation, systemic coagulation and pathogen infection.

The Role of PAR2 in TGF-ß1-Induced ERK Activation and Cell Motility.

BACKGROUND: Recently, the expression of proteinase-activated receptor 2 (PAR2) has been shown to be essential for activin receptor-like kinase 5 (ALK5)/SMAD-mediated signaling and cell migration by transforming growth factor (TGF)-ß1. However, it is not known whether activation of non-SMAD TGF-ß signaling (e.g., RAS-RAF-MEK-extracellular signal-regulated kinase (ERK) signaling) is required for cell migration and whether it is also dependent on PAR2. METHODS: RNA interference was used to deplete cells of PAR2, followed by xCELLigence technology to measure cell migration, phospho-immunoblotting to assess ERK1/2 activation, and co-immunoprecipitation to detect a PAR2-ALK5 physical interaction. RESULTS: Inhibition of ERK signaling with the MEK inhibitor U0126 blunted the ability of TGF-ß1 to induce migration in pancreatic cancer Panc1 cells. ERK activation in response to PAR2 agonistic peptide (PAR2-AP) was strong and rapid, while it was moderate and delayed in response to TGF-ß1. Basal and TGF-ß1-dependent ERK, but not SMAD activation, was blocked by U0126 in Panc1 and other cell types indicating that ERK activation is downstream or independent of SMAD signaling. Moreover, cellular depletion of PAR2 in HaCaT cells strongly inhibited TGF-ß1-induced ERK activation, while the biased PAR2 agonist GB88 at 10 and 100 µM potentiated TGF-ß1-dependent ERK activation and cell migration. Finally, we provide evidence for a physical interaction between PAR2 and ALK5. Our data show that both PAR2-AP- and TGF-ß1-induced cell migration depend on ERK activation, that PAR2 expression is crucial for TGF-ß1-induced ERK activation, and that the functional cooperation of PAR2 and TGF-ß1 involves a physical interaction between PAR2 and ALK5.

Perlecan Heparan Sulfate Is Required for the Inhibition of Smooth Muscle Cell Proliferation by All-trans-Retinoic Acid.

Smooth muscle cell (SMC) proliferation is a key process in stabilization of atherosclerotic plaques, and during restenosis after interventions. A clearer understanding of SMC growth regulation is therefore needed to design specific anti-proliferative therapies. Retinoic acid has been shown to inhibit proliferation of SMCs both in vitro and in vivo and to affect the expression of extracellular matrix molecules. To explore the mechanisms behind the growth inhibitory activity of retinoic acid, we hypothesized that retinoids may induce the expression of perlecan, a large heparan sulfate proteoglycan with anti-proliferative properties. Perlecan expression and accumulation was induced in murine SMC cultures by all-trans-retinoic acid (AtRA). Moreover, the growth inhibitory effect of AtRA on wild-type cells was greatly diminished in SMCs from transgenic mice expressing heparan sulfate-deficient perlecan, indicating that the inhibition is perlecan heparan sulfate-dependent. In addition, AtRA influenced activation and phosphorylation of PTEN and Akt differently in wild-type and mutant SMCs, consistent with previous studies of perlecan-dependent SMC growth inhibition. We demonstrate that AtRA regulates perlecan expression in SMCs and that the inhibition of SMC proliferation by AtRA is, at least in part, secondary to an increased expression of perlecan and dependent upon its heparan sulfate-chains.

Thrombin receptor protease-activated receptor 4 is a key regulator of exaggerated intimal thickening in diabetes mellitus.

BACKGROUND: Diabetes mellitus predisposes to thrombotic and proliferative vascular remodeling, to which thrombin contributes via activation of protease-activated receptor (PAR) 1. However, the use of PAR-1 inhibitors to suppress remodeling may be limited by severe bleeding. We recently reported upregulation of an additional thrombin receptor, PAR-4, in human vascular smooth muscle cells exposed to high glucose and have now examined PAR-4 as a novel mediator linking hyperglycemia, hypercoagulation, and vascular remodeling in diabetes mellitus. METHODS AND RESULTS: PAR-4 expression was increased in carotid atherectomies and saphenous vein specimens from diabetic versus nondiabetic patients and in aorta and carotid arteries from streptozotocin-diabetic versus nondiabetic C57BL/6 mice. Vascular PAR-1 mRNA was not increased in diabetic mice. Ligated carotid arteries from diabetic mice developed more extensive neointimal hyperplasia and showed greater proliferation than arteries from nondiabetic mice. The augmented remodeling response was absent in diabetic mice deficient in PAR-4. At the cellular level, PAR-4 expression was controlled via the mRNA stabilizing actions of human antigen R, which accounted for the stimulatory actions of high glucose, angiotensin II, and H2O2 on PAR-4 expression, whereas cicaprost via protein kinase A activation counteracted this effect. CONCLUSIONS: PAR-4 appears to play a hitherto unsuspected role in diabetic vasculopathy. The development of PAR-4 inhibitors might serve to limit mainly proliferative processes in restenosis-prone diabetic patients, particularly those patients in whom severe bleeding attributed to selective PAR-1 blockade or complete thrombin inhibition must be avoided or those who do not require anticoagulation.

Aspirin and lipid mediators in the cardiovascular system.

Aspirin is an unique compound because it bears two active moieties within one and the same molecule: a reactive acetyl group and the salicylate metabolite. Salicylate has some effects similar to aspirin, however only at higher concentrations, usually in the millimolar range, which are not obtained at conventional antiplatelet aspirin doses of 100-300 mg/day. Pharmacological actions of aspirin in the cardiovascular system at these doses are largely if not entirely due to target structure acetylation. Several classes of lipid mediators become affected: Best known is the cyclooxygenase-1 (COX-1) in platelets with subsequent inhibition of thromboxane and, possibly, thrombin formation. By this action, aspirin also inhibits paracrine thromboxane functions on other lipid mediators, such as the platelet storage product sphingosine-1-phosphate (S1P), an inflammatory mediator. Acetylation of COX-2 allows for generation of 15-(R)HETE and subsequent formation of "aspirin-triggered lipoxin" (ATL) by interaction with white cell lipoxygenases. In the cardiovascular system, aspirin also acetylates eNOS with subsequent upregulation of NO formation and enhanced expression of the antioxidans heme-oxygenase-1. This action is possibly also COX-2/ATL mediated. Many more acetylation targets have been identified in live cells by quantitative acid-cleavable activity-based protein profiling and might result in discovery of even more aspirin targets in the near future.

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.

Sphingosine 1-phosphate as a link between blood coagulation and inflammation.

Sphingosine 1-phosphate (S1P) is a multifunctional signaling lipid generated from sphingosine by sphingosine kinases. S1P formation has been shown in numerous cells in the circulation, including platelets, vascular endothelial and smooth muscle cells and monocytes. S1P also exerts multiple effects on these cells, i.e. cell proliferation and migration, activation of proinflammatory signaling pathways and release of additional inflammatory mediators. Similar activities and targets have also been identified for activated clotting factors such as thrombin or the activated factor-X (FXa), suggesting a possible involvement of S1P in thrombus-associated cellular signaling and thrombin-induced inflammatory reactions. Several levels of S1P-mediated, thrombin /FXa-induced signaling have already been identified: regulation of sphingosine kinase expression and activity, stimulation of S1P release from platelets and other cells and, possibly regulation of S1P-receptors on target cells. This review summarizes the current state of knowledge about S1P as a clotting factor-regulated molecular link between blood coagulation and inflammation. It is concluded that S1P might represent an until now underestimated lipid mediator of inflammatory reactions following activation of the clotting system and, in this context, also involved in the development and progression of atherosclerosis.

Potentially modifiable correlates of functional status in patients with chronic heart failure.

BACKGROUND: Chronic heart failure (CHF) patients suffer from multiple and agonizing symptoms like shortness of breath and reduced functional status, the latter of which is usually assessed using New York Heart Association (NYHA) functional class. PURPOSE: In order to identify potentially modifiable factors of reduced functional status in patients with CHF, we investigated somatic and psychosocial correlates of NYHA functional class. We subsequently compared the results to correlates of left ventricular ejection fraction (LVEF) as an objective parameter of disease severity. METHODS: The cross-sectional study (n = 314) was part of the German Heart Failure Network. Data were analysed using a logistic regression modelling process. RESULTS: In the final regression model, NYHA functional class was only significantly associated with depression (odds ratio (OR) = 1.18; 95% confidence interval (CI) = 1.09-1.27) and multimorbidity (OR = 1.17; 95% CI = 1.04-1.32). LVEF was associated with amino-terminal pro-brain natriuretic peptide (NT-proBNP) (OR = 0.60; 95% CI = 0.44-0.82), aetiology of CHF (OR = 2.08; 95% CI = 1.11-3.90), and smoking (OR = 2.21; 95% CI = 1.25-3.91). CONCLUSIONS: Whereas LVEF was not related to depression, our data revealed a close association between functional status (as assessed by NYHA functional class) and depression in patients with CHF, even after adjusting for cardiac and socio-demographic variables. Different forms of underlying causal mechanisms could be suspected; it appears promising to further investigate this specific interaction. In any event, pending further investigation, our results underscore the need to examine CHF patients with respect to both somatic symptom burden and potential depressive disorders.