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Self-extracellular RNA (eRNA), released from stressed or injured cells upon various pathological situations such as ischemia-reperfusion-injury, has been shown to act as an alarmin by inducing procoagulatory and proinflammatory responses. In particular, M1-polarization of macrophages by eRNA resulted in the expression and release of a variety of cytokines, including tumor necrosis factor (TNF)-α or interleukin-6 (IL-6). The present study now investigates in which way self-eRNA may influence the response of macrophages towards various Toll-like receptor (TLR)-agonists. Isolated agonists of TLR2 (Pam2CSK4), TLR3 (PolyIC), TLR4 (LPS), or TLR7 (R848) induced the release of TNF-α in a concentration-dependent manner in murine macrophages, differentiated from bone marrow-derived stem cells by mouse colony stimulating factor. Here, the presence of eRNA shifted the dose-response curve for Pam2CSK4 (Pam) considerably to the left, indicating that eRNA synergistically enhanced the cytokine liberation from macrophages even at very low Pam-levels. The synergistic activation of TLR2 by eRNA/Pam was duplicated by other TLR2-agonists such as FSL-1 or Pam3CSK4. In contrast, for TLR4-agonists such as LPS a synergistic effect of eRNA was much weaker, and was not existent for TLR3-, or TLR7-agonists. The synergistic eRNA/Pam action was dependent on the NFκB-signaling pathway as well as on p38MAP- and MEK1/ERK-kinases and was prevented by predigestion of eRNA with RNase1 or by antibodies against TLR2. Thus, the presence of self-eRNA as alarming molecule sensitizes innate immune responses towards pathogen-associated molecular patterns (PAMPs) in a synergistic way and may thereby contribute to the differentiated outcome of inflammatory responses.
Background: Recognizing patients at risk for pulmonary complications (PC) is of high clinical relevance. Migration of polymorphonuclear leukocytes (PMN) to inflammatory sites plays an important role in PC, and is tightly regulated by specific chemokines including interleukin (IL)−8 and other mediators such as leukotriene (LT)B4. Previously, we have reported that LTB4 indicated early patients at risk for PC after trauma. Here, the relevance of LTB4 to indicating lung integrity in a newly established long-term porcine severe trauma model (polytrauma, PT) was explored.
Methods: mTwelve pigs (3 months old, 30 ± 5 kg) underwent PT including standardized femur fracture, lung contusion, liver laceration, hemorrhagic shock, subsequent resuscitation and surgical fracture fixation. Six animals served as controls (sham). After 72 h lung damage and inflammatory changes were assessed. LTB4 was determined in plasma before the experiment, immediately after trauma, and after 2, 4, 24 or 72 h. Bronchoalveolar lavage (BAL)-fluid was collected prior and after the experiment.
Results: Lung injury, local gene expression of IL-8, IL-1β, IL-10, IL-18 and PMN-infiltration into lungs increased significantly in PT compared with sham. Systemic LTB4 increased markedly in both groups 4 h after trauma. Compared with declined plasma LTB4 levels in sham, LTB4 increased further in PT after 72 h. Similar increase was observed in BAL-fluid after PT.
Conclusions: In a severe trauma model, sustained changes in terms of lung injury and inflammation are determined at day 3 post-trauma. Specifically, increased LTB4 in this porcine long-term model indicated a rapid inflammatory alteration both locally and systemically. The results support the concept of LTB4 as a biomarker for PC after severe trauma and lung contusion.
Recent advances in basic cardiovascular research as well as their translation into the clinical situation were the focus at the last "New Frontiers in Cardiovascular Research meeting". Major topics included the characterization of new targets and procedures in cardioprotection, deciphering new players and inflammatory mechanisms in ischemic heart disease as well as uncovering microRNAs and other biomarkers as versatile and possibly causal factors in cardiovascular pathogenesis. Although a number of pathological situations such as ischemia-reperfusion injury or atherosclerosis can be simulated and manipulated in diverse animal models, also to challenge new drugs for intervention, patient studies are the ultimate litmus test to obtain unequivocal information about the validity of biomedical concepts and their application in the clinics. Thus, the open and bidirectional exchange between bench and bedside is crucial to advance the field of ischemic heart disease with a particular emphasis of understanding long-lasting approaches in cardioprotection.
Background: The treatment of different skin conditions with spa waters is a long tradition dating back to at least late Hellenism. Interestingly, independent scientific examinations studying the effect of spa waters are scarce.
Objective: In the present in vitro study, we compared the effect of culture media supplemented with (a) thermal spa waters (La Roche-Posay, Avène) and (b) two natural mineral drinking waters (Heppinger, Adelholzener) on physiological parameters in HaCaT keratinocytes.
Methods: The different medium preparations were investigated with regard to cell proliferation and cell damage. Moreover, the impact on inflammation parameters with and without ultraviolet B (UVB) irradiation was examined.
Results: Two popular thermal spring waters were found to suppress cell proliferation and cell damage. Moreover, these waters reversed the induction of interleukin-6, as measured using enzyme-linked immunosorbent assay and promoter transactivation, and the formation of reactive oxygen species after UVB stimulation. Of note, the two natural mineral waters, which are distributed as drinking waters, had some effect on the above-mentioned parameters but to a lesser extent.
Conclusion: In summary, our results show that spa waters, and particularly those derived from thermal springs, reduce parameters associated with inflammation. It seems likely that trace elements such as selenium and zinc are critical for the observed effects.
Dendritic cells (DCs) are the cutting edge in innate and adaptive immunity. The major functions of these antigen-presenting cells are the capture, endosomal processing and presentation of antigens, providing them an exclusive ability to provoke adaptive immune responses and to induce and control tolerance. Immature DCs capture and process antigens, migrate towards secondary lymphoid organs where they present antigens to naive T cells in a well-synchronized sequence of procedures referred to as maturation. Indeed, recent research indicated that sphingolipids are modulators of essential steps in DC homeostasis. It has been recognized that sphingolipids not only modulate the development of DC subtypes from precursor cells but also influence functional activities of DCs such as antigen capture, and cytokine profiling. Thus, it is not astonishing that sphingolipids and sphingolipid metabolism play a substantial role in inflammatory diseases that are modulated by DCs. Here we highlight the function of sphingosine 1-phosphate (S1P) on DC homeostasis and the role of S1P and S1P metabolism in inflammatory diseases.
Background: The phagocytic enzyme myeloperoxidase (MPO) acts as a front-line defender against microorganisms. However, increased MPO levels have been found to be associated with complex and calcified atherosclerotic lesions and incident cardiovascular disease. Therefore, this study aimed to investigate a predictive role of MPO, a biomarker of inflammation and oxidative stress, for total and cardiovascular mortality in patients referred to coronary angiography.
Methods and results: MPO plasma concentrations along with eight MPO polymorphisms were determined in 3036 participants of the Ludwigshafen Risk and Cardiovascular Health study (median follow-up 7.75 years). MPO concentrations were positively associated with age, diabetes, smoking, markers of systemic inflammation (interleukin-6, fibrinogen, C-reactive protein, serum amyloid A) and vascular damage (vascular cellular adhesion molecule-1 and intercellular adhesion molecule-1) but negatively associated with HDL-cholesterol and apolipoprotein A-I. After adjustment for cardiovascular risk factors MPO concentrations in the highest versus the lowest quartile were associated with a 1.34-fold risk (95% CI: 1.09–1.67) for total mortality. In the adjusted model the hazard ratio for cardiovascular mortality in the highest MPO quartile was 1.42 (95% CI: 1.07–1.88). Five MPO polymorphisms were positively associated with MPO concentrations but not with mortality. Using Mendelian randomization, we did not obtain evidence for a causal association of MPO with either total or cardiovascular mortality.
Conclusions: MPO concentrations but not genetic variants at the MPO locus are independently associated with risk for total and cardiovascular mortality in coronary artery disease patients.
The small leucine-rich proteoglycans (SLRPs) are biologically active components of the extracellular matrix (ECM), consisting of a protein core with leucine rich-repeat (LRR) motifs covalently linked to glycosaminoglycan (GAG) side chains. The diversity in composition resulting from the various combinations of protein cores substituted with one or more GAG chains along with their pericellular localization enables SLRPs to interact with a host of different cell surface receptors, cytokines, growth factors, and other ECM components, leading to modulation of cellular functions. SLRPs are capable of binding to: (i) different types of collagens, thereby regulating fibril assembly, organization, and degradation; (ii) Toll-like receptors (TLRs), complement C1q, and tumor necrosis factor-alpha (TNFα), regulating innate immunity and inflammation; (iii) epidermal growth factor receptor (EGF-R), insulin-like growth factor receptor (IGF-IR), and c-Met, influencing cellular proliferation, survival, adhesion, migration, tumor growth and metastasis as well as synthesis of other ECM components; (iv) low-density lipoprotein receptor-related protein (LRP-1) and TGF-β, modulating cytokine activity and fibrogenesis; and (v) growth factors such as bone morphogenic protein (BMP-4) and Wnt-I-induced secreted protein-1 (WISP-1), controlling cell proliferation and differentiation. Thus, the ability of SLRPs, as ECM components, to directly or indirectly regulate cell-matrix crosstalk, resulting in the modulation of various biological processes, aptly qualifies these compounds as matricellular proteins.
End-stage renal disease has been denominated a vasculopathic state, owing to the accelerated arterial stiffening, which occurs in addition to and independent of atherosclerosis and bears an increased cardiovascular risk. The altered metabolic milieu in uraemia leads to an increased oxidative stress, heightened inflammatory burden, and an abnormal calcium-phosphate metabolism, which are thought to be responsible for the vascular changes. The pulse wave velocity (PWV) is a widely employed surrogate parameter of arteriosclerosis. The purpose of this study was to gain more insight into the pathogenesis of arterial stiffness, by investigating the influence of markers of oxidative stress, procoagulation, and inflammation, and of the calcium-phosphate product on the PWV. We conducted a cross-sectional study in 53 stable patients aged 59 ± 16 years, who had been on haemodialysis for at least 4 months (68 ± 48). Carotid-radial PWV was measured using a semi-automated device, Complior SP (Artech Medical, France). Advanced glycosylation end-products (AGE) and advanced oxidation protein products (AOPP), were quantified according to previously described methods. High sensitive CRP was measured using ELISA, whereas the other biochemical parameters, i.e. fibrinogen, albumin, calcium, phosphate, cholesterol, and triglycerides, were determined using routine methods. For statistical calculations we employed SPSS (Statistical Package of Social Science, 12.0, 2003). The correlations between PWV, as the dependent variable, and many dependent variables were assessed by means of multiple regression analysis, in which we controlled for the influence of the traditional cardiovascular risk factors and some of the patients’ medication (calcium-channel blockers and statins). PWV was found to be significantly correlated to serum CRP (p=0.003), LDLcholesterol (p<0.001), triglycerides (p<0.001), AGE (p=0.002), calcium (p<0.001), phosphate (p=0.001), and fibrinogen (p=0.020). Between PWV and dialysis duration (months) an interesting quadratic relationship (p=0.058) was noted. Against expectation, regression analysis showed a negative correlation between AOPP and PWV (p=0.001). We failed to confirm the correlation between PWV and age, systolic blood pressure, or heart rate. Among traditional cardiovascular risk factors only LDL-cholesterol was positively correlated to PWV. In this cross-sectional analysis we could put forward that PWV correlates positively and significantly with fibrinogen, CRP, AGEs, calcium, phosphate, and LDL-cholesterol in haemodialysis patients. It seems procoagulatory and proinflammatory pathways, oxidative stress, and the calcium-phosphate product exert a synergistic effect on disturbances of vascular architecture in ESRD patients.
Atherosklerotische Stenosen der Karotiden sind eine häufige Erkrankung mit variablem Verlauf und stellen durch ihre potentielle Emboligenität einen wichtigen Risikofaktor für zerebrale Ischämien dar. Klinische und paraklinische Parameter helfen, das individuelle Schlaganfallrisiko bei Patienten mit hochgradigen ACI-Stenosen einzuschätzen, das unmittelbar nach einem thrombembolischen Ereignis besonders hoch ist. Als histomorphologisches Korrelat dieser "Vulnerabilität" wird die Ruptur der fibrotischen Deckplatte der Plaque propagiert, die häufiger bei symptomatischen Patienten nachzuweisen ist. Sie korreliert mit der Infiltration der Gefäßwand durch aktivierte Leukozyten, die über molekulare und zelluläre Interaktionen die Zell- und Bindegewebskomposition der Plaque verändern können. Die strukturelle Integrität atherosklerotischer Läsionen beruht auf der extrazellulären Vernetzung von kollagenem Bindegewebe, das überwiegend von phänotypisch veränderten glatten Gefäßmuskelzellen produziert wird. Eine Hypothese besagt, dass die im Rahmen der Inflammation stattfindende Zunahme proapoptotischer Mediatoren über eine Ausdünnung der zellulären und bindegewebigen Strukturen zu einem Verlust an mechanischer Stabilität führt und somit eine symptomatische Ruptur begünstigt. Da der Nachweis einer Ruptur mit Exponierung des thrombogenen nekrotischen Kerns allerdings nur in einem Teil der symptomatischen Plaques und umgekehrt auch in einem Teil der asymptomatischen nachgewiesen werden kann, ist aber bislang unklar, ob o.g. Abläufe in der humanen Karotis-Atherosklerose tatsächlich mit einer klinischen Relevanz einhergehen. In der vorliegenden Arbeit wurde daher das Auftreten der Apoptose von glatten Gefäßmuskelzellen (mittels DNA in situ end labeling Technik, TUNEL-Färbung) in 38 prospektiv gesammelten Endarterektomie-Präparaten hochgradiger Karotisstenosen quantitativ erfasst und statistisch in Beziehung gesetzt zu Parametern der Plaque-Instabilität, klinisch definiert durch kürzliche (< 60 Tage zurückliegende) ischämische Ereignisse (n=19) und histopathologisch definiert über den Nachweis einer Plaque-Ruptur (n=14). Außerdem wurde eine morphometrische Analyse der einzelnen Plaque-Komponenten durchgeführt und deren Ergebnisse zu den zellulären und klinischen Parametern in Beziehung gesetzt. Die Morphometrie ergab keine signifikanten Unterschiede zwischen symptomatischen vs. asymptomatischen und rupturierten vs. unrupturierten Plaques was die Größe der fibrotischen Deckplatte, die durchschnittliche Dicke (Kern-Lumen-Distanz) und die dünnsten bzw. dicksten Stellen der Deckplatte anbelangt. Anzahl und Konzentration apoptotischer glatter Muskelzellen war deutlich (p<0,001) erhöht in symptomatischen, klinisch instabilen, Karotisplaques. Allerdings waren die Apoptose-Raten in Präparaten, die eine Plaque-Ruptur aufwiesen, nicht signifikant erhöht. Darüber hinaus fand sich kein Hinweis darauf, dass erhöhte Apoptose-Raten zu einem quantifizierbaren Verlust glatter Gefäßmuskelzellen in der fibrotischen Deckplatte führen. Auf dem Boden dieser Ergebnisse kann gefolgert werden, dass erhöhten Apoptose-Raten glatter Gefäßmuskelzellen in der humanen Atherosklerose offenbar eine tragende Bedeutung bei der Entwicklung thrombembolischer Ereignisse zukommt. Allerdings wird die Annahme, dass erhöhte Apoptose-Raten über einen Verlust an glatten Gefäßmuskelzellen Einfluss auf die morphometrischen Eigenschaften der fibrotischen Deckplatte atherosklerotischer Karotis-Läsionen nehmen und zu deren Ausdünnung führen durch die vorliegende Untersuchung nicht gestützt. Vielmehr scheint es plausibel, dass die Apoptose glatter Muskelzellen im Rahmen inflammatorischer Prozesse Einfluss auf die Komposition der Karotisplaque nimmt und so über eine Desintegration der zellulären und bindegewebigen Bestandteile zu reduzierter mechanischer Widerstandskraft und Rupturneigung führt.