University Medical Center Tuebingen

Tübingen, Germany

University Medical Center Tuebingen

Tübingen, Germany
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Siemoneit U.,University of Tübingen | Koeberle A.,University of Tübingen | Rossi A.,University of Naples Federico II | Dehm F.,University of Tübingen | And 9 more authors.
British Journal of Pharmacology | Year: 2011

Background and Purpose Frankincense, the gum resin derived from Boswellia species, showed anti-inflammatory efficacy in animal models and in pilot clinical studies. Boswellic acids (BAs) are assumed to be responsible for these effects but their anti-inflammatory efficacy in vivo and their molecular modes of action are incompletely understood. Experimental Approach A protein fishing approach using immobilized BA and surface plasmon resonance (SPR) spectroscopy were used to reveal microsomal prostaglandin E2synthase-1 (mPGES1) as a BA-interacting protein. Cell-free and cell-based assays were applied to confirm the functional interference of BAs with mPGES1. Carrageenan-induced mouse paw oedema and rat pleurisy models were utilized to demonstrate the efficacy of defined BAs in vivo. Key Results Human mPGES1 from A549 cells or in vitro-translated human enzyme selectively bound to BA affinity matrices and SPR spectroscopy confirmed these interactions. BAs reversibly suppressed the transformation of prostaglandin (PG)H2to PGE2mediated by mPGES1 (IC50= 3-10 μM). Also, in intact A549 cells, BAs selectively inhibited PGE2generation and, in human whole blood, β-BA reduced lipopolysaccharide-induced PGE2biosynthesis without affecting formation of the COX-derived metabolites 6-keto PGF1αand thromboxane B2. Intraperitoneal or oral administration of β-BA (1 mg·kg-1) suppressed rat pleurisy, accompanied by impaired levels of PGE2and β-BA (1 mg·kg-1, given i.p.) also reduced mouse paw oedema, both induced by carrageenan. Conclusions and Implications Suppression of PGE2formation by BAs via interference with mPGES1 contribute to the anti-inflammatory effectiveness of BAs and of frankincense, and may constitute a biochemical basis for their anti-inflammatory properties. © 2010 The British Pharmacological Society.


Pergola C.,Friedrich - Schiller University of Jena | Jazzar B.,University of Tübingen | Rossi A.,University of Naples Federico II | Northoff H.,University Medical Center Tuebingen | And 3 more authors.
British Journal of Pharmacology | Year: 2012

Background and purpose Leukotrienes (LTs) are pro-inflammatory mediators produced by 5-lipoxygenase (5-LO). Currently available 5-LO inhibitors either lack efficacy or are toxic and novel approaches are required to establish a successful anti-LT therapy. Here we provide a detailed evaluation of the effectiveness of the plant-derived alkaloid tryptanthrin as an inhibitor of LT biosynthesis. Experimental approach We analysed LT formation and performed mechanistic studies in human neutrophils stimulated with pathophysiologically relevant stimuli (LPS and formyl peptide), as well as in cell-free assays (neutrophil homogenates or recombinant human 5-LO) and in human whole blood. The in vivo effectiveness of tryptanthrin was evaluated in the rat model of carrageenan-induced pleurisy. Key results Tryptanthrin potently reduced LT-formation in human neutrophils (IC50= 0.6 μM). However, tryptanthrin is not a redox-active compound and did not directly interfere with 5-LO activity in cell-free assays. Similarly, tryptanthrin did not inhibit the release of arachidonic acid, the activation of MAPKs, or the increase in [Ca2+]i, but it modified the subcellular localization of 5-LO. Moreover, tryptanthrin potently suppressed LT formation in human whole blood (IC50= 10 μM) and reduced LTB4levels in the rat pleurisy model after a single oral dose of 10 mg·kg-1. Conclusions and implications Our data reveal that tryptanthrin is a potent natural inhibitor of cellular LT biosynthesis with proven efficacy in whole blood and is effective in vivo after oral administration. Its unique pharmacological profile supports further analysis to exploit its pharmacological potential. © 2011 The British Pharmacological Society.


Schaible A.M.,Friedrich - Schiller University of Jena | Koeberle A.,Friedrich - Schiller University of Jena | Northoff H.,University Medical Center Tuebingen | Lawrenz B.,University Hospital of Tuebingen | And 4 more authors.
Prostaglandins Leukotrienes and Essential Fatty Acids | Year: 2013

Pregnancy is accompanied by major immunological changes to maintain both tolerance for the fetus and immune competence. Leukotrienes are powerful 5-lipoxygenase-derived inflammatory mediators and the characteristics of leukotriene-related diseases (e.g., asthma, allergic rhinitis) change during pregnancy. Here, we show that pregnancy affects leukotriene synthesis in human blood and leukocytes. 5-Lipoxygenase product formation in stimulated blood of pregnant women was significantly higher than in non-pregnant females. Although a pregnancy-related increase in neutrophil and monocyte counts may explain these observations, granulocytes of pregnant donors have lower leukotriene-synthetic capacities. On the other hand, granulocytes from non-pregnant woman produced more leukotrienes when resuspended in plasma of pregnant women than of non-pregnant females. Together, we show that leukotriene biosynthesis in maternal blood is increased by the interrelations of higher leukocyte numbers, lower cellular capacity for leukotriene synthesis and stimulatory effects of plasma. This bias may affect leukotriene-related diseases during pregnancy and their pharmacological treatment. © 2013 Elsevier Ltd.


Pergola C.,Friedrich - Schiller University of Jena | Schaible A.M.,Friedrich - Schiller University of Jena | Nikels F.,Friedrich - Schiller University of Jena | Dodt G.,University of Tübingen | And 2 more authors.
Pharmacological Research | Year: 2015

5-Lipoxygenase (5-LO), the key enzyme in the biosynthesis of pro-inflammatory leukotrienes (LTs) from arachidonic acid, is regulated by androgens in human neutrophils and monocytes accounting for sex differences in LT formation. Here we show that progesterone suppresses the synthesis of 5-LO metabolites in human primary monocytes. 5-LO product formation in monocytes stimulated with Ca2+-ionophore A23187 or with lipopolysaccharide/formyl peptide was suppressed by progesterone at concentrations of 10-100 nM in cells from females and at 1 μM in cells from males. Progesterone down-regulated 5-LO product formation in a rapid and reversible manner, but did not significantly inhibit 5-LO activity in cell-free assays using monocyte homogenates. Also, arachidonic acid release and its metabolism to other eicosanoids in monocytes were not significantly reduced by progesterone. The inhibitory effect of progesterone on LTs was still observed when mitogen-activated protein kinases were pharmacologically blocked, stimulatory 1-oleoyl-2-acetyl-sn-glycerol was exogenously supplied, or extracellular Ca2+ was removed by chelation. Instead, suppression of PKA by means of two different pharmacological approaches (i.e. H89 and a cell-permeable PKA inhibitor peptide) prevented inhibition of 5-LO product generation by progesterone, to a similar extent as observed for the PKA activators prostaglandin E2 and 8-Br-cAMP, suggesting the involvement of PKA. In summary, progesterone affects the capacity of human primary monocytes to generate 5-LO products and, in addition to androgens, may account for sex-specific effects on pro-inflammatory LTs. © 2015 Elsevier Ltd. All rights reserved.


Maier S.,Albert Ludwigs University of Freiburg | Szalkowski A.,Albert Ludwigs University of Freiburg | Kamphausen S.,Albert Ludwigs University of Freiburg | Kamphausen S.,University Medical Center Tuebingen | And 8 more authors.
PLoS ONE | Year: 2012

Recent studies have begun to carve out a specific role for the rostral part of the dorsal medial prefrontal cortex (dmPFC) and adjacent dorsal anterior cingulate cortex (dACC) in fear/anxiety. Within a novel general framework of dorsal mPFC/ACC areas subserving the appraisal of threat and concomitant expression of fear responses and ventral mPFC/ACC areas subserving fear regulation, the rostral dmPFC/dACC has been proposed to specifically mediate the conscious, negative appraisal of threat situations including, as an extreme variant, catastrophizing. An alternative explanation that has not been conclusively ruled out yet is that the area is involved in fear learning. We tested two different fear expression paradigms in separate fMRI studies (study 1: instructed fear, study 2: testing of Pavlovian conditioned fear) with independent groups of healthy adult subjects. In both paradigms the absence of reinforcement precluded conditioning. We demonstrate significant BOLD activation of an identical rostral dmPFC/dACC area. In the Pavlovian paradigm (study 2), the area only activated robustly once prior conditioning had finished. Thus, our data argue against a role of the area in fear learning. We further replicate a repeated observation of a dissociation between peripheral-physiological fear responding and rostral dmPFC/dACC activation, strongly suggesting the area does not directly generate fear responses but rather contributes to appraisal processes. Although we succeeded in preventing extinction of conditioned responding in either paradigm, the data do not allow us to definitively exclude an involvement of the area in fear extinction learning. We discuss the broader implications of this finding for our understanding of mPFC/ACC function in fear and in negative emotion more generally. © 2012 Maier et al.


Pergola C.,Friedrich - Schiller University of Jena | Jazzar B.,University of Tübingen | Rossi A.,University of Naples Federico II | Buehring U.,University of Tübingen | And 5 more authors.
Journal of Pharmacology and Experimental Therapeutics | Year: 2011

Lipoxygenases (LOs) are iron-containing enzymes that catalyze the conversion of arachidonic acid into hydroperoxyeicosatetraenoic acids (HPETEs) and other bioactive lipid mediators. In mammals, 5-LO, 15-LO, and 12-LO enzymes seem to have distinct roles in pathophysiological contexts, which have emphasized the need for selective inhibitors. Cinnamyl-3,4-dihydroxy-α- cyanocinnamate (CDC) has been proposed as potent and selective inhibitor of platelet-type 12-LO (p12-LO). Here, we re-evaluated the selectivity profile of CDC on LOs, and we show that CDC is a potent and direct inhibitor of 5-LO. CDC reduced 5-LO activity in cell-free assays (purified human recombinant enzyme or leukocyte homogenates), with IC50 values in the low nanomolar range (9-25 nM) and a selectivity index of approximately 35 and 15 over p12-LO and 15-LO1, respectively. Likewise, CDC inhibited 5-LO product formation in intact human polymorphonuclear leukocytes and monocytes (IC50 = 0.45-0.8 μM). A lower potency was observed for 15-LO1, whereas p12-LO activity in platelets was hardly affected. In human whole blood, CDC efficiently reduced the formation of 5-LO products, and similar effects were observed for 12(S)-H(P)ETE and 15(S)-H(P)ETE. Finally, CDC (3.5 and 7 mg/kg i.p.) was effective in vivo in the platelet-activating factor-induced shock in mice and reduced formation of the 5-LO product leukotriene B4 in the rat carrageenan-induced pleurisy after a single oral dose of 10 mg/kg. Together, our data demonstrate that CDC is a potent inhibitor of 5-LO with efficacy in vivo and encourage further development of CDC as the lead compound. Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics.


Maier S.J.,Albert Ludwigs University of Freiburg | Szalkowski A.,Albert Ludwigs University of Freiburg | Kamphausen S.,University Medical Center Tuebingen | Feige B.,Albert Ludwigs University of Freiburg | And 7 more authors.
Psychological Medicine | Year: 2014

Background Emotional dysregulation is becoming increasingly recognized as an important feature of attention deficit hyperactivity disorder (ADHD). In this study, two experiments were conducted investigating the neural response to either verbally instructed fear (IF) or uninstructed (classically conditioned) fear (UF) using the skin conductance response (SCR) and functional magnetic resonance imaging (fMRI). Method In the conditioning phase of the UF experiment (17 ADHD and 17 healthy controls), subjects experienced an unconditioned stimulus (UCS, unpleasant electrodermal stimulation) paired with a former neutral conditioned stimulus (CS+), whereas a control stimulus (CS-) was never paired with the UCS. In the subsequent test phase, only the CS+ and the CS-were presented. In the IF experiment (13 ADHD and 17 healthy controls), subjects were only told that an independently experienced UCS might occur together with the CS+ but not the CS-during testing. No UCS was presented. Results Groups did not detectably differ in SCR or neural responses to UF. In IF, ADHD patients showed a trend-line decreased SCR and significantly decreased activation of the dorsal anterior cingulate cortex (dACC), a region prominently involved in fear responding, to the CS+. This was accompanied by higher amygdala activation to the CS-. Conclusions During IF, ADHD patients showed deficits in regions centrally involved in fear learning and expression in terms of diminished CS+-related dACC and increased CS-related amygdala signals. This suggests an impaired processing of verbally transmitted aversive information, which is central for conveying fear information in social contexts. This result extends the growing literature on emotional alterations in ADHD. © 2013 Cambridge University Press.


PubMed | University Medical Center Tuebingen, University of Ulm, University of Mannheim, Albert Ludwigs University of Freiburg and University of Heidelberg
Type: Journal Article | Journal: Journal of cancer education : the official journal of the American Association for Cancer Education | Year: 2016

End-of-life care is an essential element of quality cancer care. Nevertheless, a majority of physicians and nurses working at cancer centers feel unprepared for this task. As part of a larger survey study, we investigated what suggestions experienced physicians and nurses have to improve education/training on end-of-life care. In an open question, participants were requested to suggest changes to the end-of-life curriculum for physicians and nurses. Answers to this question were content analyzed using the qualitative data analysis software MAXQDA. Physicians and nurses at 10 cancer centers throughout Baden-Wuerttemberg were surveyed. From the total 1131 survey participants, 675 (483 nurses, 167 physicians, 25 unknown) responded to the open question regarding suggestions for education/training in end-of-life care. Two main categories were inductively developed: (1) format (i.e., structure and method of teaching) and (2) content (i.e., knowledge and know-how required for care of the dying). Regarding format, both professional groups most often wished for more practical experiences with dying patients (e.g., internships at hospices). Regarding content, physicians and nurses most frequently requested (1) more basic information on palliative care, (2) increased skills training in communication, and (3) knowledge of how to appropriately care for patients caregivers. The results of our analysis reflect already trained physicians and nurses interest in furthering their knowledge and skills to care for dying patients. The suggestions of experienced physicians and nurses should be integrated into the further development of palliative care curricula.


PubMed | University Medical Center Tuebingen
Type: Journal Article | Journal: Artificial organs | Year: 2016

The catheter-based Impella 5.0 left ventricular assist device is a powerful and less invasive alternative for patients in cardiogenic shock. The use as second-line therapy in patients with precedent extracorporeal life support (ECLS) has not been described before now. We analyzed our experience of consecutive patients treated with this alternative strategy. From April 2014 to December 2014, eight patients had been implanted as a second-line option after ECLS support. The reason for the change from ECLS to Impella 5.0 was absence of cardiac recovery for primary weaning and complications of ECLS therapy. The mean time of ECLS support prior to Impella implantation was 127 days. The implantation of the Impella 5.0/CP was technically successful in all patients, and the ECLS could be explanted in all eight patients who received Impella implantation as a second-line treatment. The second-line Impella 5.0 therapy resulted in two patients who turned into left ventricular assist device (LVAD) candidates, two primary weaning candidates, and four patients who died in the setting of sepsis or absent cardiac recovery and contraindications for durable LVAD therapy. Thereby, the overall hospital discharge survival as well as the 180-day survival was 50% for Impella 5.0 implantations as second-line procedure after ECLS. The latest follow-up survival of this second-line strategy after ECLS was three out of eight, as one patient died after 299 days of LVAD support due to sepsis. The use of Impella 5.0 constitutes a possible second-line therapeutic option for those patients who do not show cardiac recovery during prolonged ECLS support or suffer from complications of ECLS therapy. This treatment allows additional time for decisions regarding cardiac recovery or indication for durable LVAD therapy.


PubMed | University of Tübingen, Friedrich - Schiller University of Jena and University Medical Center Tuebingen
Type: | Journal: Pharmacological research | Year: 2015

5-Lipoxygenase (5-LO), the key enzyme in the biosynthesis of pro-inflammatory leukotrienes (LTs) from arachidonic acid, is regulated by androgens in human neutrophils and monocytes accounting for sex differences in LT formation. Here we show that progesterone suppresses the synthesis of 5-LO metabolites in human primary monocytes. 5-LO product formation in monocytes stimulated with Ca(2+)-ionophore A23187 or with lipopolysaccharide/formyl peptide was suppressed by progesterone at concentrations of 10-100 nM in cells from females and at 1 M in cells from males. Progesterone down-regulated 5-LO product formation in a rapid and reversible manner, but did not significantly inhibit 5-LO activity in cell-free assays using monocyte homogenates. Also, arachidonic acid release and its metabolism to other eicosanoids in monocytes were not significantly reduced by progesterone. The inhibitory effect of progesterone on LTs was still observed when mitogen-activated protein kinases were pharmacologically blocked, stimulatory 1-oleoyl-2-acetyl-sn-glycerol was exogenously supplied, or extracellular Ca(2+) was removed by chelation. Instead, suppression of PKA by means of two different pharmacological approaches (i.e. H89 and a cell-permeable PKA inhibitor peptide) prevented inhibition of 5-LO product generation by progesterone, to a similar extent as observed for the PKA activators prostaglandin E2 and 8-Br-cAMP, suggesting the involvement of PKA. In summary, progesterone affects the capacity of human primary monocytes to generate 5-LO products and, in addition to androgens, may account for sex-specific effects on pro-inflammatory LTs.

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