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In dit hoofdstuk komen eerst de voedingsnormen voor vitamines, de begrippen aanbevolen dagelijkse hoeveelheid (ADH) en adequate inname (AI), en de wijze waarop deze tot stand komen aan de orde. Wat de inname van afzonderlijke nutriënten vanuit de voeding betreft heeft zich de afgelopen decennia een belangrijke verandering in denken en beleidsontwikkeling voorgedaan, namelijk een verschuiving van richtlijnen, gebaseerd op voedingsstoffen, naar richtlijnen, gebaseerd op voedingsmiddelen en voedingspatronen. Naast vitamines die van nature in voedingsmiddelen voorkomen, kunnen ook voedingssupplementen en producten waaraan vitamines zijn toegevoegd bijdragen aan de behoefte. Er bestaan diverse supplementen die een of meerdere vitamines bevatten. Het is belangrijk om onderscheid te maken tussen voedingskundige en farmacologische toepassing van vitamines. In het laatste deel van dit hoofdstuk wordt ingegaan op een aantal algemene aspecten van het analyseren van vitamines in bloed (of serum, plasma). Daarbij gaat het vooral om het nut van dergelijke bepalingen, hun mogelijkheden en beperkingen.

Een adequate vitamine-inname is zeker niet vanzelfsprekend, en deficiënties door bijvoorbeeld ondervoeding, eenzijdige voeding, medicijngebruik of andere factoren blijven wereldwijd een probleem. Voor sommige vitamines is de optimale inname of concentratie nog steeds onderwerp van discussie. In dit hoofdstuk ligt de nadruk op de fysiologische aspecten van vitamines, hun opname en effecten in het lichaam. Het is vooral gericht op de diëtist die zich wil verdiepen in de basisprincipes, achtergronden en recente ontwikkelingen rond vitamines. Dertien voor de mens relevante vitamines komen één voor één aan de orde, daarbij aantekenend dat het belang van hun onderlinge samenhang in de voedingsmatrix en het eetpatroon maakt dat we ze eigenlijk niet afzonderlijk zouden moeten bespreken. De laatste jaren is over sommige vitamines meer geschreven en gediscussieerd dan over andere. Voorbeelden zijn vitamine B6 (vooral in verband met overdosering), vitamine B12, vitamine C, vitamine D en vitamine K2. Deze ontwikkelingen krijgen in dit hoofdstuk daarom extra aandacht.

Introduction: Strenuous physical stress induces a range of physiological responses, the extent depending, among others, on the nature and severity of the exercise, a person's training level and overall physical resilience. This principle can also be used in an experimental set-up by measuring time-dependent changes in biomarkers for physiological processes. In a previous report, we described the effects of workload delivered on a bicycle ergometer on intestinal functionality. As a follow-up, we here describe an analysis of the kinetics of various other biomarkers. Aim: To analyse the time-dependent changes of 34 markers for different metabolic and immunological processes, comparing four different exercise protocols and a rest protocol. Methods: After determining individual maximum workloads, 15 healthy male participants (20-35 years) started with a rest protocol and subsequently performed (in a cross-over design with 1-week wash-out) four exercise protocols of 1-h duration at different intensities: 70% W max in a hydrated and a mildly dehydrated state, 50% W max and intermittent 85/55% W max in blocks of 2 min. Perceived exertion was monitored using the Borg' Rating of Perceived Exertion scale. Blood samples were collected both before and during exercise, and at various timepoints up to 24 h afterward. Data was analyzed using a multilevel mixed linear model with multiple test correction. Results: Kinetic changes of various biomarkers were exercise-intensity-dependent. Biomarkers included parameters indicative of metabolic activity (e.g., creatinine, bicarbonate), immunological and hematological functionality (e.g., leukocytes, hemoglobin) and intestinal physiology (citrulline, intestinal fatty acid-binding protein, and zonulin). In general, responses to high intensity exercise of 70% W max and intermittent exercise i.e., 55/85% W max were more pronounced compared to exercise at 50% W max . Conclusion: High (70 and 55/85% W max ) and moderate (50% W max ) intensity exercise in a bicycle ergometer test produce different time-dependent changes in a broad range of parameters indicative of metabolic activity, immunological and hematological functionality and intestinal physiology. These parameters may be considered biomarkers of homeostatic resilience. Mild dehydration intensifies these time-related changes. Moderate intensity exercise of 50% W max shows sufficient physiological and immunological responses and can be employed to test the health condition of less fit individuals.

Glucagon like peptide-1 (GLP-1) and serotonin are both involved in food intake regulation. GLP-1 release is stimulated upon nutrient interaction with G-protein coupled receptors by enteroendocrine cells (EEC), whereas serotonin is released from enterochromaffin cells (ECC). The central hypothesis for the current study was that nutrient-induced GLP-1 release from EECs is modulated by serotonin through a process involving serotonin receptor interaction. This was studied by assessing the effects of serotonin reuptake inhibition by fluoxetine on nutrient-induced GLP-1, PYY and CCK release from isolated pig intestinal segments. Next, serotonin-induced GLP-1 release was studied in enteroendocrine STC-1 cells, where effects of serotonin receptor inhibition were studied using specific and non-specific antagonists.Casein (1% w/v), safflower oil (3.35% w/v), sucrose (50 mM) and rebaudioside A (12.5 mM) stimulated GLP-1 release from intestinal segments, whereas casein only stimulated PYY and CCK release. Combining nutrients with fluoxetine further increased nutrient-induced GLP-1, PYY and CCK release.Serotonin release from intestinal tissue segments was stimulated by casein and safflower oil while sucrose and rebaudioside A had no effect. The combination with fluoxetine (0.155 μM) further enhanced casein and safflower oil induced-serotonin release.Exposure of ileal tissue segments to serotonin (30 μM) stimulated GLP-1 release whereas it did not induce PYY and CCK release. Serotonin (30 and 100 μM) also stimulated GLP-1 release from STC-1 cells, which was inhibited by the non-specific 5HT receptor antagonist asenapine (1 and 10 μM). These data suggest that nutrient-induced GLP-1 release is modulated by serotonin through a receptor mediated process. © 2016 The Authors.

Over het effect van geneesmiddelgebruik op de voedingsstatus bij ouderen is relatief weinig bekend. Ondanks de hoge prevalentie van ondervoeding en deficiënties in deze kwetsbare leeftijdsgroep, worden de klinische gevolgen van voedingstekorten bij oudere patiënten vaak niet opgemerkt, of gezien als symptomen van ouderdom of comorbiditeit. Daarnaast is in geneesmiddelonderzoek evaluatie van voeding-geneesmiddelinteracties (VGI's) niet verplicht. Vijf verschillende klassen van VGI's worden besproken: het effect van nutriënten, voeding of voedingstoestand op geneesmiddelwerking en het effect van geneesmiddelgebruik op voedingstoestand of deficiënties, met de focus op vitamine D, foliumzuur, magnesium en vitamine B12. Deze systematische benadering van VGI's is een tool voor uitbreiding van dit kennisgebied in onderzoek en implementatie van deze materie in de praktijk.

Background. Anorexia is a common symptom among cancer patients and contributes to malnutrition and strongly impinges on quality of life. Cancer-induced anorexia is thought to be caused by an inability of food intake-regulating systems in the hypothalamus to respond adequately to negative energy balance during tumour growth. Here, we show that this impaired response of food-intake control is likely to be mediated by altered serotonin signalling and by failure in post-transcriptional neuropeptide Y (NPY) regulation.MethodsTwo tumour cachectic mouse models with different food intake behaviours were used: a C26-colon adenocarcinoma model with increased food intake and a Lewis lung carcinoma model with decreased food intake. This contrast in food intake behaviour between tumour-bearing (TB) mice in response to growth of the two different tumours was used to distinguish between processes involved in cachexia and mechanisms that might be important in food intake regulation. The hypothalamus was used for transcriptomics (affymetrix chips).ResultsIn both models, hypothalamic expression of orexigenic NPY was significantly higher compared with controls, suggesting that this change does not directly reflect food intake status but might be linked to negative energy balance in cachexia. Expression of genes involved in serotonin signalling showed to be different between C26-TB mice and Lewis lung carcinoma-TB mice and was inversely associated with food intake. In vitro, using hypothalamic cell lines, serotonin repressed neuronal hypothalamic NPY secretion while not affecting messenger NPY expression, suggesting that serotonin signalling can interfere with NPY synthesis, transport, or secretion.ConclusionsAltered serotonin signalling is associated with changes in food intake behaviour in cachectic TB mice. Serotonins' inhibitory effect on food intake under cancer cachectic conditions is probably via affecting the NPY system. Therefore, serotonin regulation might be a therapeutic target to prevent the development of cancer-induced eating disorders.

Background and Purpose N-docosahexaenoylethanolamine (DHEA) is the ethanolamine conjugate of the long-chain polyunsaturated n-3 fatty acid docosahexaenoic (DHA; 22: 6n-3). Its concentration in animal tissues and human plasma increases when diets rich in fish or krill oil are consumed. DHEA displays anti-inflammatory properties in vitro and was found to be released during an inflammatory response in mice. Here, we further examine possible targets involved in the immune-modulating effects of DHEA. Experimental Approach Antagonists for cannabinoid (CB)1 and CB2 receptors and PPAR¿ were used to explore effects of DHEA on NO release by LPS-stimulated RAW264.7 cells. The possible involvement of CB2 receptors was studied by comparing effects in LPS-stimulated peritoneal macrophages obtained from CB2-/- and CB2+/+ mice. Effects on NF-¿B activation were determined using a reporter cell line. To study DHEA effects on COX-2 and lipoxygenase activity, 21 different eicosanoids produced by LPS-stimulated RAW264.7 cells were quantified by LC-MS/MS. Finally, effects on mRNA expression profiles were analysed using gene arrays followed by Ingenuity® Pathways Analysis. Key Results CB1 and CB2 receptors or PPARs were not involved in the effects of DHEA on NO release. NF-¿B and IFN-ß, key elements of the myeloid differentiation primary response protein D88 (MyD88)-dependent and MyD88-independent pathways were not decreased. By contrast, DHEA significantly reduced levels of several COX-2-derived eicosanoids. Gene expression analysis provided support for an effect on COX–2-mediated pathways. Conclusions and Implications Our findings suggest that the anti-inflammatory effects of DHEA in macrophages predominantly take place via inhibition of eicosanoids produced through COX-2.

Background - In rodent models, caloric restriction (CR) with maintenance of adequate micronutrient supply has been reported to increase lifespan and to reduce age-induced muscle loss (sarcopenia) during ageing. In the present study, we further investigated effects of CR on the onset and severity of sarcopenia in ageing male C57BL/6¿J mice. The aim of this study was to investigate whether CR induces changes in behaviour of the animals that could contribute to the pronounced health-promoting effects of CR in rodents. In addition, we aimed to investigate in more detail the effects of CR on the onset and severity of sarcopenia. Methods - The mice received either an ad libitum diet (control) or a diet matching 70 E% of the control diet (C). Daily activity, body composition (dual energy X-ray absorptiometry), grip strength, insulin sensitivity, and general agility and balance were determined at different ages. Mice were killed at 4, 12, 24, and 28¿months. Skeletal muscles of the hind limb were dissected, and the muscle extensor digitorum longus muscle was used for force-frequency measurements. The musculus tibialis was used for real-time quantitative PCR analysis. Results - From the age of 12¿months, CR animals were nearly half the weight of the control animals, which was mainly related to a lower fat mass. In the control group, the hind limb muscles showed a decline in mass at 24 or 28¿months of age, which was not present in the CR group. Moreover, insulin sensitivity (oral glucose tolerance test) was higher in this group and the in vivo and ex vivo grip strength did not differ between the two groups. In the hours before food was provided, CR animals were far more active than control animals, while total daily activity was not increased. Moreover, agility test indicated that CR animals were better climbers and showed more climbing behaviours. Conclusions - Our study confirms earlier findings that in CR animals less sarcopenia is present. The mice on the CR diet, however, showed specific behavioural changes characterized by higher bursts of activity within a short time frame before consumption of a 70 E% daily meal. We hypothesize that the positive effects of CR on muscle maintenance in rodents are not merely a direct consequence of a lower energy intake but also related to a more active behaviour in a specific time frame. The burst of activity just before immediate start of eating, might lead to a highly effective use of the restricted protein sources available

Contains fulltext : 32642.pdf (Publisher’s version ) (Closed access) In this study the anti-inflammatory properties of zilpaterol, a beta2-adrenergic receptor (AR) agonist specifically developed as a growth promoter in cattle were investigated. Although zilpaterol has a different structure compared with the beta2-AR agonists known to date, it was noted that it was able to bind to both the beta2-AR (Ki = 1.1 x 10(-6)) and the beta1-AR (Ki = 1.0 x 10(-5)). Using lipopolysaccharide (LPS)-exposed U937 macrophages, the production of cyclic adenosine-3',5'-cyclic monophosphate (cAMP) and tumor necrosis factor alpha (TNF-alpha) were investigated. Zilpaterol inhibited TNF-alpha release and induced intracellular cAMP levels in a dose-dependent manner. The inhibition of TNF-alpha release and induction of cAMP production was mainly mediated via the beta2-AR, as indicated by addition of beta1- and beta2-specific antagonists. The effects of zilpaterol were investigated in LPS-treated male Wistar rats after pretreatment with zilpaterol. Zilpaterol dosed at 500 microg/kg body weight reduced the TNF-alpha plasma levels. In conclusion, zilpaterol is a beta2-adrenergic agonist and an inhibitor of TNF-alpha production induced by LPS both in vivo and in vitro.

On September 29, 2011, acknowledged experts in the field of vitamin D, mainly European, were brought together in order to discuss the recent scientific advances in relation to vitamin D: the current requirements and associations with various health outcom

N-3 long chain polyunsaturated fatty acids (n-3 LC PUFAs), in particular a-linolenic acid (18:3n-3), eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) are receiving much attention because of their presumed beneficial health effects. To explain these, a variety of mechanisms have been proposed, but their interactions with the endocannabinoid system have received relatively little attention so far. However, it has already been shown some time ago that consumption of n-3 LC PUFAs not only affects the synthesis of prototypic endocannabinoids like anandamide, but also stimulates the formation of specific n-3 LC PUFA-derived conjugates with ethanolamine, dopamine, serotonin or other amines. Some of these fatty amides show overlapping biological activities with those of typical endocannabinoids, whereas others possess distinct and sometimes largely unknown receptor affinities and other properties. The ethanolamine and dopamine conjugates of DHA have been the most investigated thus far. These mediators may provide promising new leads to in the field of inflammatory and neurological disorders and for other pharmacological applications, including their use as carrier molecules for neurotransmitters to target the brain. Furthermore, combinations of n-3 LC PUFA-derived fatty acid amides, their precursors and FAAH inhibitors offer possibilities to optimise their effects in health and disease.

In 2007 publiceerden Wageningen-UR, TNO en RIVM samen met ZonMW het rapport 'Wat gaan we eten?' Een van de aanbevelingen was om tot meer samenhang en afstemming in het onderzoek te komen. Sindsdien stemmen de drie kennisinstituten hun activiteiten voor de ministeries van VWS en LNV op elkaar af. Het parapluproject dat sindsdien is opgestart 'Gezondheidseffecten van groenten en fruit', heeft tot doel de kennisbehoefte van overheid, maatschappelijke praktijkgerichte organisaties en wetenschap in kaart te brengen. In dit geval met betrekking tot obesitas, een belangrijk probleem waarmee de maatschappij zich geconfronteerd ziet

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Het voorkómen van ongewenste interacties tussen medicatie en voeding zou onderdeel moeten zijn van de behandeling van patiënten met chronische hart- en vaatziekten. De diëtist moet dan wel beschikken over meer kennis over geneesmidddelen.

De nadruk van dit rapport ligt op de volgende twee vragen: 1) In hoeverre kan voeding het gebruik van geneesmiddelen in het algemeen in verpleeghuizen beïnvloeden? Hierbij valt onderscheid te maken in: a) Wat is de rol van omgevingsinvloeden (sociale context)? b) Voedingsproducten: welke specifieke producten kunnen medicijngebruik verminderen? 2) Wat is de kostenefficiëntie van de vervanging van medicijnen door gezonde voedingsproducten? In hoeverre betekent investeren in voeding een besparing op medicijnen of verpleging?

In hoeverre kan de voeding een rol spelen bij de behandeling van een ziekte of mogelijk zelfs de genezing bevorderen? Waar houdt de rol van voeding op en waar begint de farmacotherapie? De kloof tussen voeding en farma wordt echter smaller en op sommige terreinen is er sprake van een verregaande integratie. Het vakgebied van de klinische voeding ontwikkelt zich erg snel

In hoeverre kan de voeding een rol spelen bij de behandeling van een ziekte of mogelijk zelfs de genezing bevorderen? Waar houdt de rol van voeding op en waar begint de farmacotherapie? De kloof tussen voeding en farma wordt echter smaller en op sommige terreinen is er sprake van een verregaande integratie. Het vakgebied van de klinische voeding ontwikkelt zich erg snel

The introduction of the concept of systems biology, enabling the study of living systems from a holistic perspective based on the profiling of a multitude of biochemical components, opens up a unique and novel opportunity to reinvestigate natural products. In the study of their bioactivity, the necessary reductionistic approach on single active components has been successful in the discovery of new medicines, but at the same time the synergetic effects of components were lost. Systems biology, and especially metabolomics, is the ultimate phenotyping. It opens up the possibility of studying the effect of complex mixtures, such as those used in Traditional Chinese Medicine, in complex biological systems; abridging it with molecular pharmacology. This approach is considered to have the potential to revolutionize natural product research and to advance the development of scientific based herbal medicine. Copyright © 2005 John Wiley & Sons, Ltd.

In this study the anti-inflammatory properties of zilpaterol, a β2-adrenergic receptor (AR) agonist specifically developed as a growth promoter in cattle were investigated. Although zilpaterol has a different structure compared with the β2-AR agonists known to date, it was noted that it was able to bind to both the β2-AR (K i = 1.1 × 10-6) and the β1-AR (Ki = 1.0 × 10-5). Using lipopolysaccharide (LPS)-exposed U937 macrophages, the production of cyclic adenosine-3′, 5′-cyclic monophosphate (cAMP) and tumor necrosis factor alpha (TNF-α) were investigated. Zilpaterol inhibited TNF-α release and induced intracellular cAMP levels in a dose-dependent manner. The inhibition of TNF-α release and induction of cAMP production was mainly mediated via the β2-AR, as indicated by addition of β1- and β2-specific antagonists. The effects of zilpaterol were investigated in LPS-treated male Wistar rats after pretreatment with zilpaterol. Zilpaterol dosed at 500 μg/kg body weight reduced the TNF-α plasma levels. In conclusion, zilpaterol is a β2-adrenergic agonist and an inhibitor of TNF-α production induced by LPS both in vivo and in vitro. © 2005 Blackwell Publishing Ltd.

Two-dimensional difference gel electrophoresis (DIGE) in combination with univariate (Student's t-test) and multivariate data analysis, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to study the anti-inflammatory effects of the β2-adrenergic receptor (β2-AR) agonist zilpaterol. U937 macrophages were exposed to the endotoxin lipopolysaccharide (LPS) to induce an inflammatory reaction, which was inhibited by the addition of zilpaterol (LZ). This inhibition was counteracted by addition of the β2-AR antagonist propranolol (LZP). The extracellular proteome of the U937 cells induced by the three treatments were examined by DIGE. PCA was used as an explorative tool to investigate the clustering of the proteome dataset. Using this tool, the dataset obtained from cells treated with LPS and LZP were separated from those obtained from LZ treated cells. PLS-DA, a multivariate data analysis tool that also takes correlations between protein spots and class assignment into account, correctly classified the different extracellular proteomes and showed that many proteins were differentially expressed between the proteome of inflamed cells (LPS and LZP) and cells in which the inflammatory response was inhibited (LZ). The Student's t-test revealed 8 potential protein biomarkers, each of which was expressed at a similar level in the LPS and LZP treated cells, but differently expressed in the LZ treated cells. Two of the identified proteins, macrophage inflammatory protein-1beta (MIP-1β) and macrophage inflammatory protein-1 alpha (MIP-1α) are known secreted proteins. The inhibition of MIP-1β by zilpaterol and the involvement of the β2-AR and cAMP were confirmed using a specific immunoassay. © 2005 American Chemical Society.

This review discusses some of the recent developments in genomics and its current and future relevance for veterinary pharmacology and toxicology. With the rapid progress made in this field several new approaches in pharmacological and toxicological research have developed and drug discovery and drug development strategies have changed dramatically. In this review, the term genomics is used to encompass the three sub-disciplines transcriptomics, proteomics and metabolomics (or metabonomics) to describe the formation and fate of mRNA, proteins and metabolites, respectively. The current status and methods of the technology and some applications are briefly described. Although the DNA sequencing programmes are receiving considerable attention, the real value of genomics for pharmacology and toxicology is brought by the parallel developments in bio-informatics, bio-statistics and the integration of biology with mathematics and information technology. The ultimate level of integration is now mostly called systems biology, where mRNA, proteins and metabolites are being analysed in parallel, using a complete arsenal of analytical techniques (DNA-array, LC-MS/MS, GC-MS/MS, NMR, etc.). The information thus collected is analysed, integrated, linked to database information and translated to pathways and systems. This approach offers an enormous potential to study disease mechanisms and find new drug targets. Thus far, genomics and systems biology have not been introduced significantly in typical veterinary pharmacological and toxicological research programmes. The high costs and complexity connected to these large projects often form major obstacles for research groups with limited budgets. In other veterinary areas and disciplines, including infectious diseases, animal production and food-safety more examples of application are available. Genomics and bio-informatics provide outstanding opportunities to study pharmacology and toxicology in a more holistic way, taking into account the complexity of biological systems and based on the basic principles of physiology and the concept of homeostasis. Knowledge of biology, in vivo and in vitro models, and comparative pharmacology/toxicology is essential here, creating excellent opportunities for the veterinary trained scientist. © 2005 Blackwell Publishing Ltd.

The discovery of new anti-inflammatory drugs is often based on an interaction with a specific target, although other pathways often play a primary or secondary role. Anti-inflammatory drugs can be categorized into classes, based on their mechanism of action. In this article we investigate the possibility to characterize novel anti-inflammatory compounds by three holistic methods. For this purpose, we make use of macrophage-like U937 cells which are stimulated with LPS in the absence or presence of an anti-inflammatory compound. Using micro-arrays, 2-D gel electrophoresis and a LC-MS method for lipids the effects on the transcriptome, proteome and metabolome of the exposed cells is investigated. The expression patterns are subsequently analyzed using in-house developed pattern recognition tools. Using the methods described above, we have examined the effects of six anti-inflammatory compounds. Our results demonstrate that different classes of anti-inflammatory compounds show distinct and characteristic mRNA, protein, and lipid expression patterns, which can be used to categorise known molecules and to discover and classify new leads. The potential of our approach is illustrated by the analysis of several beta (2)-adrenergic agonists (β2-agonists). In addition to their primary pharmacological target, β2-agonists posses certain anti-inflammatory properties. We were able to show that zilpaterol, a poorly characterized β2-agonist, gives rise to an almost identical expression pattern as the β2-agonists clenbuterol and salbutamol. Furthermore we have identified specific mRNA, protein and lipid markers for the anti-inflammatory compounds investigated in this study. © 2004 Elsevier B.V. All rights reserved. Chemicals/CAS: 4 (4 fluorophenyl) 2 (4 methylsulfinylphenyl) 5 (4 pyridyl)imidazole, 152121-47-6; clenbuterol, 21898-19-1, 37148-27-9; dexamethasone, 50-02-2; formoterol, 73573-87-2; salbutamol, 18559-94-9; Adrenergic beta-Agonists; Anti-Inflammatory Agents; Lipids; lipopolysaccharide, Escherichia coli 0111 B4; Lipopolysaccharides; Proteome; Receptors, Adrenergic, beta-2; RNA, Messenger

Objective and Design: To investigate the effects of β2- adrenoceptor (β2-AR) stimulation on endotoxin-induced liver damage and systemic cytokine levels in rats. Subjects: Standard male Wistar rats. Treatment: A disease-model of lipolysaccharide (LPS)-induced acute systemic inflammation was used. The β2-selective AR agonist clenbuterol was administered before, during, and after LPS-challenge to investigate its effects on the acute inflammatory response and associated liver-failure. Methods: The following parameters have been measured in plasma: TNFα, IL-1β, IL-6, IL-10, AST, ALT, and Bilirubin. Liver histological examination was performed to look for changes in tissue morphology. Results: Administration of clenbuterol (p.o.) one hour before, or intravenous at the same time as LPS-challenge resulted in a marked reduction of plasma levels of TNFα, IL-1β, and IL-6. A change both in plasma-level and in time-concentration profile of the anti-inflammatory cytokine IL-10 was found. Clenbuterol minimized LPS-induced liver damage, as represented by significantly lowered concentrations of several parameters for liver-failure (AST, ALT, Bilirubin), and improved hepatic tissue morphology. Clenbuterol administration after LPS challenge failed to inhibit TNFα-release but reduced liver-damage. Simultaneous use of the β2-AR antagonist propranolol augmented LPS-induced liver failure, suggesting a role of endogenous adrenoceptor-agonists in prevention of organ-failure during systemic inflammation. Conclusions: The results indicate that a selective β2-AR agonist might be used as an additional therapeutic agent in the clinic for the treatment of (acute) systemic inflammatory disorders in order to reduce or prevent subsequent liver failure.

Previous research has shown that β-adrenoceptor (β-AR) agonists have potent anti-inflammatory capabilities, e.g. represented by suppression of release of the proinflammatory cytokines. Aim of this research was to determine whether the effects of β-agonists on LPS-induced TNFα and IL-10 release are influenced by their different stereochemistry. In addition, the role of the β-AR subtypes was studied. The effect of two stereoisomers of the selective β2-AR agonist TA2005 [(R,R)- and (S,S)-] on the LPS-induced TNFα and IL-10 release by U937 macrophages was compared. The (R,R)-stereoisomer was 277 times more potent in inhibiting the TNFα release than the (S,S)-form. The (R,R)-stereoisomer also appeared to be more potent in increasing the IL-10 release. In radioligand binding studies the affinity of (R,R)-TA2005 for the β-adrenoceptor was 755 times higher than the (S,S)-TA2005 stereoisomer. In addition, the elevation of intracellular cAMP in U937 cells appeared to be stereoselective: (R,R)-TA2005 was more potent in elevating intracellular cAMP. The effect of both stereoisomers on the LPS-induced TNFα release could almost completely be antagonized by preincubation with the selective β2-AR-antagonist ICI-118551. Further evidence that the effect of the β-agonists is mediated via the β2-adrenoceptor subtype exclusively was acquired by incubation of U937 cells with selective β1- and β3-agonists. None of these receptor subtype agonists showed significant suppressive effect on TNFα release. This study provides additional proof that the anti-inflammatory effects of β2-agonists are mediated via the β2-adrenoceptor and indicates that these effects are highly dependent on the stereoselectivity of the ligand.

Current veterinary residue analysis mainly focuses on the monitoring of residues of the administered parent compound. However, it is possible that larger amounts of metabolites are excreted and that they can have a prolonged excretion period. In order to unravel specific metabolic steps and to identify possible biological markers, two in vitro liver models were used, i.e. monolayer cultures of isolated hepatocytes and liver microsomes, both prepared from liver tissue of cattle. Clostebol, boldenone, norethandrolone (NE) and ethylestrenol (EES) were used as model substrates. Results show that the metabolic profiles derived from in vitro experiments are predictive for the in vivo metabolic pathways of the steroids evaluated in this study. By means of this strategy, it is possible to identify 17α-ethyl-5β-estrane-3α, 17β-diol (EED) as a common biological marker for NE and EES. By in vivo experiments it was shown that EED is particularly important for the detection of the abuse of NE or EES because of its high excretion levels and its prolonged presence as compared with the parent compounds or any other metabolite.