BIOM-32. DNA METHYLATION SUBCLASSES PREDICT THE BENEFIT FROM GROSS TOTAL TUMOR RESECTION IN IDH-WILDTYPE GLIOBLASTOMA PATIENTS

DNA methylation-based tumor classification allows an enhanced distinction into subgroups of glioblastoma. However, the clinical benefit of DNA methylation-based stratification of glioblastomas remains inconclusive. We performed a multicentric cohort study including 430 patients with newly diagnosed glioblastoma whose tumors were subjected to DNA methylation profiling. The primary outcome was overall survival (OS) and progression-free survival (PFS). Secondary outcomes were the prognostic relevance of EOR and MGMTpromoter methylation status as well as surgical benefit for recurrent glioblastoma. After stratifying patients in accordance with their DNA methylation subclasses RTK I, RTK II, and mesenchymal (MES), outcome analyses revealed no significant differences between these three methylation subclasses (p = 0.06). RTK I or RTK II tumors who underwent gross-total resection (GTR) or near GTR had a longer OS and PFS than partially resected patients (p < 0.01). In the MES subclass, no survival benefit for a maximized EOR was found (p = 0.33). In multivariate analysis, the therapy response-predictive value of MGMT promoter methylation was evident for RTK I (p < 0.01) and RTK II (p = 0.02) but failed to be an independent factor in the MES subclass (p= 0.06). For local recurrence, re-resection conveyed a progression-to-overall survival (POS) benefit (p < 0.01), which was evident in the RTK I (p = 0.03) and RTK II (p < 0.01) subclasses, but not in the MES subclass (p = 0.33).This study demonstrates a survival benefit from maximized EOR at surgery for newly diagnosed and recurrent glioblastomas of the RTK I and RTK II subclass but not the MES subclass. Hence, it needs to be carefully considered whether the MES subclass should be treated with maximal surgical resection, especially when located in eloquent areas and at time of recurrence.

Towards quantum simulations in particle physics and beyond on noisy intermediate-scale quantum devices

We review two algorithmic advances that bring us closer to reliable quantum simulations of model systems in high-energy physics and beyond on noisy intermediate-scale quantum (NISQ) devices. The first method is the dimensional expressivity analysis of quantum circuits, which allows for constructing minimal but maximally expressive quantum circuits. The second method is an efficient mitigation of readout errors on quantum devices. Both methods can lead to significant improvements in quantum simulations, e.g. when variational quantum eigensolvers are used. This article is part of the theme issue 'Quantum technologies in particle physics'.

Methylation and Expression of Mutant FUS in Motor Neurons Differentiated From Induced Pluripotent Stem Cells From ALS Patients

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive disease leading to degeneration of motor neurons (MNs). Epigenetic modification of gene expression is increasingly recognized as potential disease mechanism. In the present study we generated motor neurons from induced pluripotent stem cells from ALS patients carrying a mutation in the fused in sarcoma gene (FUS) and analyzed expression and promoter methylation of the FUS gene and expression of DNA methyltransferases (DNMTs) compared to healthy control cell lines. While mutant FUS neural progenitor cells (NPCs) did not show a difference in FUS and DNMT expression compared to healthy controls, differentiated mutant FUS motor neurons showed significantly lower FUS expression, higher DNMT expression and higher methylation of the proximal FUS gene promoter. Immunofluorescence revealed perceived proximity of cytoplasmic FUS aggregates in ALS MNs together with 5-methylcytosin (5-mC). Targeting disturbed methylation in ALS may therefore restore transcriptional alterations and represent a novel therapeutic strategy.

Long-term effects of chromium on morphological and immunological parameters of Wistar rats

Hexavalent chromium raises high concern because of its wide industrial applications and reported toxicity. Long-term (135 days) oral exposure of Wistar rats to chromium in the form of K₂Cr₂O₇ (exposed group~20 mg/kg/day) led to a decrease in thymus mass and thymocytes' number and caused structural and functional changes in the lymph nodes and spleen, namely lymphoreticular hyperplasia and plasmocytic macrophage transformation. Programmed cell death was increased in both thymocytes and splenocytes and decreased in lymphocytes in the T-zones of spleen and lymph nodes. Moreover, Cr (VI) administration decreased myeloid cells' and neutrophils' number, while it increased lymphoid and erythroid cells' number in bone marrow. Cr (VI) immune system effects seem to be related to oxidative stress induction, as depicted by the increased levels of diene conjugates and malondialdehyde in the spleen and liver and by the decreased activity of catalase and superoxide dismutase in rats' erythrocytes. In addition, exposure to Cr (VI) decreased copper, nickel and iron concentrations in blood and liver, while Cr levels in blood, spleen and liver were increased, as expected. The observed changes in the series of immunological parameters studied contribute to the development of new approaches for the prevention of low level Cr exposure toxicity.

G-CSF - an anti-inflammatory cytokine

We have previously reported that in various macrophage populations prepared from G-CSF treated rats LPS-inducible TNF release was suppressed. In vitro, LPS induced liver cell death only when hepatocytes were cocultured with liver macrophages. Rat Kupffer cells from G-CSF treated donor animals were less potent in mediating LPS-inducible hepatocytotoxicity in vitro than cells from control animals. These ex vivo findings were confirmed in vivo by demonstrating that G-CSF treatment attenuated LPS-inducible circulating TNF levels and protected from liver injury and mortality.

We extended these observations to humans in two studies with G-CSF treated volunteers. In a pilot study, 11 subjects were treated single-blindly with 480 μg G-CSF s.c. (n = 7) or saline placebo (n = 4). Blood was taken at different time-points relative to G-CSF injection and cytokine release capacity was assessed in LPS stimulated whole blood incubations. In blood from G-CSF treated volunteers, we found reduced LPS-inducible TNF formation while the release of both soluble TNF receptor (sTNF-R) and interleukin 1 receptor antagonist (IL-1ra) were increased. In a second double-blind, randomized and controlled study, three groups of seven volunteers were treated once or twice 24 h apart with G-CSF or solvent placebo. Besides LPS, various stimuli were included to initiate cytokine release in a whole blood assay. The reduction of TNF formation (mean 53 % at 24 h after G-CSF) was different with the various stimuli. All stimuli increased IL-1ra (mean 14-fold) and sTNF-R (mean 3-fold) at 24 h after G-CSF. LPS-inducible IFN-γ and GM-CSF were significantly reduced. Our data indicate that the pattern of cytokines produced by human whole blood taken after G-CSF treatment in response to a variety of stimuli is shifted from pro- to anti-inflammatory mediators. These findings extend the knowledge on the pharmacology of G-CSF in animal models of the systemic inflammatory response syndrome and prompt a trial of G-CSF prophylaxis with this indication.

A LUHMES 3D dopaminergic neuronal model for neurotoxicity testing allowing long-term exposure and cellular resilience analysis

Several shortcomings of current Parkinson’s disease (PD) models limit progress in identification of environmental contributions to disease pathogenesis. The conditionally immortalized cell line LUHMES promises to make human dopaminergic neuronal cultures more easily available, but these cells are difficult to culture for extended periods of time. We overcame this problem by culturing them in 3D with minor medium modifications. The 3D neuronal aggregates allowed penetration by small molecules and sufficient oxygen and nutrient supply for survival of the innermost cells. Using confocal microscopy, gene expression, and flow cytometry, we characterized the 3D model and observed a highly reproducible differentiation process. Visualization and quantification of neurites in aggregates was achieved by adding 2 % red fluorescent protein-transfected LUHMES cells. The mitochondrial toxicants and established experimental PD agents, rotenone and MPP⁺, perturbed genes involved in one-carbon metabolism and transsulfuration pathways (ASS1, CTH, and SHTM2) as in 2D cultures. We showed, for the first time in LUHMES, down-regulation of mir-7, a miRNA known to target alpha-synuclein and to be involved in PD. This was observed as early as 12 h after rotenone exposure, when pro-apoptotic mir-16 and rotenone-sensitive mir-210 were not yet significantly perturbed. Finally, washout experiments demonstrated that withdrawal of rotenone led to counter-regulation of mir-7 and ASS1, CTH, and SHTM2 genes. This suggests a possible role of these genes in direct cellular response to the toxicant, and the model appears to be suitable to address the processes of resilience and recovery in neurotoxicology and Parkinson’s disease in future studies.

The development of new concepts for assessing reproductive toxicity applicable to large scale toxicological programmes

Large scale toxicological testing programmes which are currently ongoing such as the new European chemical legislation REACH require the development of new integrated testing strategies rather than applying traditional testing schemes to thousands of chemicals. The current practice of requiring in vivo testing for every possible adverse effect endanger the success of these programmes due (i) to limited testing facilities and sufficient capacity of scientific/technical knowledge for reproductive toxicity; (ii) an unacceptable number of laboratory animals involved (iii) an intolerable number of chemicals classified as false positive. A key aspect of the implementation of new testing strategies is the determination of prevalence of reproductive toxicity in the universe of industrial chemicals. Prevalences are relevant in order to be aware on the expected rate of false classification during the toxicological testing and to implement appropriate measures for their avoidance. Furthermore, a detailed understanding on the subendpoints affected by reproductive toxicants and the underlying mechanisms will lead to more science based testing strategies integrating alternative methods without compromising the protection of consumers.

Bruton's tyrosine kinase together with PI 3-kinase are part of Toll-like receptor 2 multiprotein complex and mediate LTA induced Toll-like receptor 2 responses in macrophages

Lipoteichoic acid (LTA) of Gram-positive bacteria initiates innate immune responses via Toll-like receptor-2 (TLR2), resulting in the activation of intracellular signaling and production of inflammatory cytokines in macrophages. Although Bruton's tyrosine kinase (Btk) is biologically important molecule implicated in immune regulation and recently in TLR signaling its importance for LTA-TLR2 mediated responses has not been evaluated. In this study, we detected Btk in the LTA signaling complex with TLR2 and PI 3-kinase (PI3K). The constitutive interaction of these proteins was mediated via PI3K Src homology (SH3) -domain. Both Btk and PI3K were activated by LTA stimulation and the LTA induced cytokine expression was differentially modulated by these kinases. LTA induced the activation of nuclear factor kappaB (NFkappaB), however, only Btk inhibition affected the LTA induced Ser536 phosphorylation and DNA-binding of NFkappaB. In conclusion, our results demonstrate that Btk and PI3K occupy important roles in TLR2-induced activation of macrophages, resulting in selective regulation of cytokines.

In vitro tests to evaluate immunotoxicity: A preliminary study

The implementation of Registration, Evaluation and Authorisation of new and existing Chemicals (REACH) will increase the number of laboratory animals used, if alternative methods will not be available. In the meantime, REACH promotes the use of in vitro tests and, therefore, a set of appropriated alternative testing methods and assessment strategies are needed. The immune system can be a target for many chemicals including environmental contaminants and drugs with potential adverse effects on human health. The aim of this study was to evaluate the predictivity of a set of in vitro assays to detect immunosuppression. The tests have been performed on human, rat and murine cells. Different endpoints have been assessed: cytotoxicity, cytokine release, myelotoxicity and mitogen responsiveness. For each of these endpoints IC50s values have been calculated. Six chemical substances, representative of the full range of in vivo responses and for which good human and/or animal data are available either from databases or literature, have been selected: two chemicals classified as not immunotoxic (Urethane and Furosemide), and four (tributyltin chloride (TBTC), Verapamil, Cyclosporin A, Benzo(a)pyrene) with different effect on immune system. All the tests confirmed the strong immunotoxic effect of TBTC as well as they confirmed the negative controls. For one chemical (Verapamil) the IC50 is similar through the different tests. The IC50s obtained with the other chemicals depend on the endpoints and on the animal species. The clonogenic test (CFU-GM) and the mitogen responsiveness showed similar IC50s between human and rodent cells except for Cyclosporin A and TBTC. All different tests classified the compounds analyzed in the same way.

Toward an evidence-based toxicology

The increasing demands on toxicology of large-scale risk assessment programmes for chemicals and emerging or expanding areas of chemical use suggest it is timely to review the toxicological toolbox. Like in clinical medicine, where an evidence-based medicine (EBM) is critically reviewing traditional approaches, toxicology has the opportunity to reshape and enlarge its methodology and approaches on the basis of compounded scientific knowledge. Such revision would have to be based on structured reviews of current practice, ie, assessment of test performance characteristics, mechanistic understanding, extended quality assurance, formal validation and the use of integrated testing strategies. This form of revision could optimize the balance between safety, costs and animal welfare, explicitly stating and, where possible, quantifying uncertainties. After a self-critical reassessment of current practices and evaluation of the thus generated information, such an evidence-based toxicology (EBT) promises to make better use of resources and to increase the quality of results, facilitating their interpretation. It shall open up hazard and also risk assessments to new technologies, flexibly accommodating current and future mechanistic understanding. An EBT will be better prepared to answer the continuously growing safety demands of modern societies.

A Staphylococcus aureus lipoteichoic acid (LTA) derived structural variant with two diacylglycerol residues

Based on 1,2-O-isopropylidene-sn-glycerol five chiral building blocks containing differently modified glycerol residues were required for the synthesis of the target molecule 2. One of these building blocks is diacylglyceryl beta-gentiobioside carrying a phosphite residue at 6b-O position. Ligation of these five building blocks led to the desired glycerol phosphate backbone to which d-alanyl residues were attached, thus generating after O-deprotection the target molecule 2, a bisamphiphilic structural variant of Staphylococcus aureus LTA. This compound displayed higher potency in terms of cytokine release by human blood leukocytes than the monoamphiphilic variant LTA.

Pyrogen testing of lipidic parenterals with a novel in vitro test--application of the IPT based on cryopreserved human whole blood

The European Pharmacopoeia has made the testing of small volume parenterals (< 15) obligatory since 2004. This concerns many formulations, e.g. vitamins, steroids and hormones, many of which are applied intramuscularly using a lipidic carrier. Lipopolysaccharides, the best established endotoxins from Gram-negative bacteria, bind strongly to lipophilic substances, which mask them in Limulus amebocyte lysate assays. End-product testing, therefore, can only be carried out in rabbit pyrogen tests. This will lead to a pronounced increase in animal experiments if no alternative procedures become available. We have described a novel in vitro pyrogen test (IPT) based on human whole blood, which has recently been validated in a collaborative study including the European Pharmacopoeia. Here, the utility of the IPT for lipophilic substances and lipid-containing end-products was assessed. For a variety of lipids commonly added to formulations of injectable endproducts, namely peanut oil, sesame oil, miglyol and paraffin, a protocol which allows interference-free testing was established applying the pharmacopoeial criterion of 50 to 200% retrieval of an LPS spike. Furthermore, end-product testing for three sample formulations was possible. In all, a method could be established which allows the determination of given or calculated ELC (endotoxin limit concentrations) according to Pharmacopoeia. It is concluded that monocytes do react to lipid-bound LPS, indicating that immune responses to contaminated endproducts must be anticipated, and that the IPT is suitable for endproduct control of these formulations.

The effects of solvents on embryonic stem cell differentiation

Dimethyl sulfoxide (DMSO) and ethanol are common organic solvents used for dissolving lipophilic substances for in vitro testing. However, DMSO is known to induce differentiation in embryonic stem (ES) and embryonic teratocarcinoma (EC) cells. In order to clarify if solvents like DMSO and ethanol have an influence on in vitro developmental toxicity test systems, the presented study has evaluated their effects on differentiation by using different test systems. ES and EC cells were transfected with a construct containing the mTert promoter combined with the green fluorescent protein gene (GFP). A down-regulation of mTert, a marker for undifferentiated cells, results in a lower expression of GFP, which could be measured by flow cytometry. Taking the specific characteristics of ES and EC cells into account this effect could be a hint for the interaction of DMSO with embryonic development. Additionally, the effects of the solvents ethanol and DMSO on Oct-4 expression, another marker for undifferentiated cells, were measured in wild-type ES cells. Both selected molecular markers demonstrated an induction of differentiation after exposure to DMSO; in wild-type ES cells at a concentration of 0.125% and in transgenic EC cells at a concentration of 0.25% DMSO. All other differences from controls, including those which attained a level of statistical significance, were minor or not dosage related in degree, or were not consistent over time and are, therefore, considered to be of little toxicological importance. In addition, a cytotoxicity test demonstrated that the solvents affected the employed molecular markers in non-cytotoxic concentrations. The ES cells were the most sensitive towards the cytotoxic effects of the solvent DMSO while the EC cells were more sensitive when treated with the solvent ethanol.

Highly purified lipoteichoic acid from gram-positive bacteria induces in vitro blood–brain barrier disruption through glia activation: Role of pro-inflammatory cytokines and nitric oxide

The co-culture of bovine brain capillary endothelial cells and rat primary glial cells was established as an in vitro blood-brain barrier model to investigate the mechanisms by which the Gram-positive bacterial cell wall components lipoteichoic acid and muramyl dipeptide induced injury of blood-brain barrier structure and function. We found that highly purified lipoteichoic acid disrupted blood-brain barrier integrity in a concentration- and time-dependent manner indirectly, through glia activation. Low trans-endothelial electrical resistance and high permeability to fluorescein isothiocyanate-inulin observed in the presence of lipoteichoic acid-activated glial cells were potentiated by muramyl dipeptide and could be reversed only when glial cells were activated by lipoteichoic acid at 10 microg/ml but not with a higher lipoteichoic acid concentration (30 microg/ml). Immunocytochemistry analysis revealed no evident changes in the distribution of the cytoskeleton protein F-actin and tight junction proteins occludin and claudin after lipoteichoic acid treatment. However, the tight junction associated protein AHNAK clearly revealed the morphological alteration of the endothelial cells induced by lipoteichoic acid. Lipoteichoic acid-activated glial cells produced nitric oxide and pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta) that contributed to lipoteichoic acid-induced blood-brain barrier disruption, since the direct treatment of the endothelial monolayer with tumor necrosis factor-alpha or interleukin-1beta increased blood-brain barrier permeability, whereas the pre-treatment of lipoteichoic acid-activated glial cells with antibodies against these two cytokines blocked lipoteichoic acid effects. Additionally, nitric oxide was also involved in blood-brain barrier damage, since the nitric oxide donor itself (diethylenetriamine-nitric oxide adduct) increased blood-brain barrier permeability and inducible nitric oxide synthase inhibitor (1400W) partially reversed lipoteichoic acid-induced trans-endothelial electrical resistance decrease.

The prospects for using (Q)SARs in a changing political environment--high expectations and a key role for the European Commission's joint research centre

Recent policy developments in the European union (EU) and within the Organisation for Economic Cooperation and Development (OECD) have placed increased emphasis on the use of structure-activity relationships (SARs) and quantitative structure-activity relationships (QSARs), collectively referred to as (Q)SARs, within various regulatory programmes for the assessment of chemicals and products. The most significant example within the EU is the European commission's proposal (of 29 October 2003) to introduce a new system for managing chemicals (called REACH), which calls for an increased use of (Q)SARs and other non-animal methods, especially for the assessment of low production volume chemicals. Another development within the EU is the Seventh Amendment to the Cosmetics Directive, which foresees the phasing out of animal testing on cosmetics, combined with the imposition of marketing bans on cosmetics that have been tested on animals after certain deadlines. At the same time, the Existing Chemicals programme within the OECD is investigating ways of increasing the use of chemical category approaches, which depend heavily on the use of (Q)SARs, activity-activity relationships and read-across. Such developments are placing an enormous challenge on industry, regulatory bodies, and on the European commission's Joint Research Centre (JRC), which is responsible for providing independent scientific advice to policy makers in the European Commission and the Member States. This paper reviews the different scientific and regulatory purposes for which reliable (Q)SARs could be used, and describes the current work of the JRC in providing scientific support for the development, validation and implementation of (Q)SARs.

The role of the European centre for the validation of alternative methods (ECVAM) in the validation of (Q)SARs

Under the current chemicals legislation, the regulatory use of structure-activity relationships (SARs) and quantitative structure-activity relationships (QSARs), collectively referred to as (Q)SARs, for the assessment of chemicals is limited, partly due to concerns about the extent to which (Q)SAR estimates can be relied upon. On 29 October 2003, the European Commission adopted a legislative proposal that foresees the introduction of a new regulatory system for chemicals called REACH (Registration, Evaluation, and Authorisation of Chemicals), which will impose equivalent information requirements on both new and existing chemicals. For reasons of practicality, cost-effectiveness and animal welfare, it is envisaged that (Q)SARs will play an important role in the assessment of some 30,000 existing chemicals for which further information may be required under the REACH system. It will therefore be essential that the (Q)SAR models used will produce reliable estimates. To overcome the barriers in the acceptance of (Q)SARs for regulatory purposes, it is widely acknowledged that there needs to be international agreement on the principles of (Q)SAR validation, and that the process of (Q)SAR validation should be managed by independent organisations, with a view to providing independent advice to the regulators who make decisions on the acceptability of (Q)SARs. The European Centre for the Validation of Alternative Methods (ECVAM), which is part of the European Commission's Joint Research Centre (JRC), has a well-established role in providing independent scientific and technical advice to European policy makers. This paper describes progress made at an international level regarding the principles of validation, and explains the role of ECVAM regarding the practical validation of (Q)SARs.

The Use of Embryonic Stem Cells for Regulatory Developmental Toxicity Testing In Vitro - The Current Status of Test Development

The future chemical policy of the European Union as well as the 7th amendment of the cosmetic directive is calling for the development of alternative tests to animal experimentation for toxicological safety testing. In the field of embryotoxicity one of the most promising in vitro models are based on embryonic stem cells. The embryonic stem cell test has already been validated in comparison to in vivo results in an international blind collaboration study. The presented review is discussing the use, limitations and further needs for the test in order to be fully suitable for regulatory acceptance. In this context, it is summarized which requirements for an in vitro embryotoxicity test have to be fulfilled for regulatory toxicity testing. In addition, an overview about the current status of test development of other embryonic stem cell tests is presented. Several workshops have reviewed the progress of in vitro tests for developmental toxicity testing. A general consensus of these workshops has been that one single test will not be sufficient to cover all manifestations of developmental toxicity. The establishment of a test battery for developmental toxicity is required. This will be even more challenging since the principles of a composing test strategy and its validation have not been defined yet. Finally, the unique possibility of combining the human embryonic stem cell technology and the microarray techniques might lead to a deeper understanding of the toxicological mechanisms of human developmental toxicants.

Monitoring of teratogenic effects in vitro by analysing a selected gene expression pattern

The development of in vitro methods for regulatory embryotoxicity testing is challenging since the understanding of chemical effects on the mammalian development is still poor. The aim of the project is to identify marker genes during in vitro cell differentiation of murine embryonic stem cells, in order to predict chemical effects on cell differentiation of specific target tissues. The present study is focusing on the expression pattern by using semi-quantitative reverse transcriptase (RT)-PCR of key genes involved in cardiomyocytes development; i.e. Oct-4, Brachyury, Nkx2.5 and alpha myosin heavy chain (alpha-MHC). Two reference chemicals with well-known in vivo data have been analysed by using this approach: retinoic acid and lithium chloride. Retinoic acid has been selected as a teratogen affecting several target tissues, whereas lithium chloride has been described to affect the development of the cardiovascular system. We demonstrate that retinoic acid already affects in the early stage of germ layer formation, which was demonstrated by a change of Oct-4 and Brachyury gene expression. As we expected, the expression of cardiac specific genes (Nkx2.5, alpha-MHC) has been also modified. In contrary, the Oct-4 and Brachyury expression was not changed by lithium treatment. In this case, we observed a modification in the normal gene expression pattern, for alpha-MHC and Nkx2.5, demonstrating that lithium chloride affects the later stage of heart development. These data suggest that the inclusion of selective target organ genes in an established embryotoxicity test allows to predict effects of chemicals and drugs to the heart development.

[Infestation of ticks with Borrelia, and Lyme borreliosis in Germany]

Currently, borreliosis is the most common tick-borne infectious disease in Europe and the USA. In Europe, three species of Borrelia are known to be pathogenic for humans, each of which apparently give rise to different clinical symptoms. Diagnosis is based in particular on the clinical presentation and history of exposure, and, as a rule, is confirmed by serological methods. It must, however, be remembered that the humoral immune response may appear relatively late, so at an early stage, patients are still serologically negative. Depending on the stage involved, oral or peroral antibiotic treatment is applied--however, eradication of the pathogen is unsuccessful in some cases. In future, adjuvant immunotherapy might close the therapeutic gap.

Three Rs potential in the development and quality control of pharmaceuticals

The intention of a pharmaceutical company is to develop new, efficient products quick and with a minimum of costs. Compared to in vitro methods, animal experiments in general consume much more time and resources (costs as well as time to the market) than in vitro methods. Therefore, the use of whole animal models depends primarily on the judgement of their efficacy in the screening process, but the willingness to incorporate in vitro methods in general is high and is furthered by new developments such as high-throughput screening. Nevertheless, in vitro tests might be politically promoted by increasing their costs (quality controls, requested housing conditions) and duration (time to start of an experiment, sequential performance). Which models are favoured by industry to include them in a screening process: They have to be based on our most recent understanding of the respective disease, well characterised to allow interpretation of results and require only limited development time. All these aspects argue in favour of collaboration between industry and academia, where our understanding of pathophysiology is generated and mechanism based models are developed and characterised. However, technology transfer towards industry represents a bottle-neck for industrial use of these new in vitro models. New platforms to promote this transfer should be developed in order to bring together developer and user of novel in vitro systems and promote demonstration projects. Financing of such collaborations is not the key problem (the development of a single drug makes up to 500 million $) but the dilemma of publication of results: The development advantage compared to competitors depends on the exclusive use of novel models. The protection of intellectual property rights and the public interest in spreading alternatives to animal experiments must be balanced, e.g. by delayed but indispensable publication or advantages for companies employing alternatives in the regulatory approval process for a new drug. Quality control of therapeutic drugs (except hormones and blood products) represents a minor field of animal consumption with the exception of pyrogenicity testing. Despite considerable progress due to the introduction of the Limulus assay which represents the most successful in vitro alternative in use so far. However, some limitations of this in vitro test might be overcome in the near future by the currently validated human whole blood assay. During the last few years considerable progress has been made in the replacement (and deletion) of animal tests required for the potency and safety testing of hormones. This has been made possible by biotechnical production methods, by better-defined products, and because physico-chemical methods can be used for the potency testing of these products. In general, the better defined a drug is, the easier chemical, physical or in vitro techniques can be used for batch control. Control authorities should therefore urge the use of highly standardised components.

Molecular aspects of anti-inflammatory action of G-CSF

Granulocyte colony-stimulating factor (G-CSF) is a cytokine which stimulates the production of neutrophils in the bone marrow and modulates cellular functions of mature neutrophils. Besides neutrophils and their precursors, monocytes are direct target cells of G-CSF action. G-CSF influences monocyte functions in an anti-inflammatory way: The stimulation of monocytes with G-CSF results in an attenuation of LPS-induced release of IL-1beta, TNF-alpha, IL-12 and IL-18. G-CSF exerts its biological functions on neutrophils and monocytes via membrane-bound receptors. Seven different human G-CSF receptor isoforms have been described which are generated by alternative splicing. The physiologic roles of these isoforms and the expression pattern on various cell types are still unknown. The signal transduction pathway of G-CSF receptors involves the activation of JAK tyrosine kinases and STAT transcription factors and the ras/mitogen-activated protein kinase pathway.

Comparison and validation of novel pyrogen tests based on the human fever reaction

The absence of pyrogens (fever-inducing contamination) in injectable drugs is a crucial safety control because pyrogens can pose a life-threatening risk to the patient. The field of applications for pyrogen-testing is expanding and becoming more diverse due to innovative high-tech products such as medical devices, cellular therapies and species-specific agents (e.g. recombinant proteins). The overall aim of the consortium is to develop, evaluate and validate a method based on the human fever reaction to replace the rabbit pyrogen test and the Limulus assay. The network brings together the six most prominent test systems developed recently in Europe for trans-national comparison and subsequent validation of the most promising models. This pre-competitive development will initiate further applications and exploitations for new fields of pyrogen testing such as cellular therapies, medical devices and pyrogen pollution control in the work place. A method for introduction into the European Pharmacopoeia will be developed as a replacement for the rabbit pyrogen test for end-product control.

Lipopolysaccharide and ceramide docking to CD14 provokes ligand-specific receptor clustering in rafts

The glycosylphosphatidylinositol-anchored receptor CD14 plays a major role in the inflammatory response of monocytes to lipopolysaccharide. Here, we describe that ceramide, a constituent of atherogenic lipoproteins, binds to CD14 and induces clustering of CD14 to co-receptors in rafts. In resting cells, CD14 was associated with CD55, the Fcgamma-receptors CD32 and CD64 and the pentaspan CD47. Ceramide further recruited the complement receptor 3 (CD11b/CD18) and CD36 into proximity of CD14. Lipopolysaccharide, in addition, induced co-clustering with Toll-like receptor 4, Fcgamma-RIIIa (CD16a) and the tetraspanin CD81 while CD47 was dissociated. The different receptor complexes may be linked to ligand-specific cellular responses initiated by CD14.

Characteristics of surfactant protein A and D binding to lipoteichoic acid and peptidoglycan, 2 major cell wall components of gram-positive bacteria

Infection with gram-positive bacteria is a major cause of pneumonia. Surfactant proteins A (SP-A) and D (SP-D) are thought to play an important role in the innate immunity of the lung. Both proteins can bind to gram-positive bacteria. Until now, it was not known with which surface component(s) of gram-positive bacteria SP-A and SP-D interact. Lipoteichoic acid (LTA) and peptidoglycan (PepG) are components of the cell wall of gram-positive bacteria. By use of a solid phase-based binding assay, LTA of Bacillus subtilis was shown to be bound by SP-D but not by SP-A. Unmodified PepG of Staphylococcus aureus was bound by SP-D. SP-D binding to both LTA and PepG was calcium dependent and carbohydrate inhibitable. These results indicate that SP-D interacts with gram-positive bacteria via binding to the cell wall components LTA and PepG and that the carbohydrate recognition domain is responsible for this binding.

Anti-TNF-neutralizing antibodies reduce pain-related behavior in two different mouse models of painful mononeuropathy

We investigated the anti-hyperalgesic effect of neutralizing antibodies (AB) to tumor necrosis factor-alpha (TNF) in two murine models of neuropathy, the chronic constrictive sciatic nerve injury (CCI) which has a strong epineurial inflammatory component, and the partial sciatic nerve transection (PST), a 'pure' nerve injury model. In both models a single AB injection intra-operatively as well as on day 4 reduced thermal hyperalgesia significantly, whereas mechanical allodynia was only reduced with intraoperative but not with delayed treatment.

Mistletoe lectin-1 increases tumor necrosis factor-alpha release in lipopolysaccharide-stimulated whole blood via inhibition of interleukin-10 production

We examined the immunomodulatory properties of the mistletoe preparation Lektinol (standardized for mistletoe lectin-1) and recombinant mistletoe lectin-1 (rML-1) in vitro by assessing alterations in the cytokine response of human whole blood. Lektinol or rML-1 alone did not induce any cytokine release in unstimulated whole blood. However, the lipopolysaccharide (LPS)-induced release of tumor necrosis factor (TNF)-alpha was increased, and the secretion of interleukin (IL)-10 was reduced by Lektinol at a mistletoe lectin-1 (ML-1) concentration of 0.5 to 5 ng/ml, whereas the LPS-induced secretion of IL-1 beta, IL-6, IL-12, and interferon-gamma was not affected. Lektinol did not alter the initial phase of TNF-alpha production but sustained TNF-alpha levels longer than in the LPS controls. Recombinant ML-1, but not the recombinant B-chain alone, also increased TNF-alpha release and decreased IL-10 release. We propose that the increase in TNF-alpha release is due to a specific inhibition of IL-10 release by Lektinol. This conclusion is based on the observation that blocking of endogenously formed IL-10 by a neutralizing antibody results in a similar increase of TNF-alpha in the late production phase after LPS stimulation. This hypothesis was also corroborated by the finding that when endogenously formed IL-10 was blocked, Lektinol could no longer increase TNF-alpha release. These results indicate that Lektinol modulates the cytokine response of human whole blood to LPS in a proinflammatory fashion, which can be attributed to ML-1.

Whole blood cytokine response as a measure of immunotoxicity

Immunotoxicity, although increasingly recognized as a potential hazard, still lacks standardized in vivo and in vitro models. The considerable species differences and species-specific effects in immune responses prompt the development of human in vitro test systems. Immunotoxic reactions comprise activation (inflammatory processes, autoaggressive processes, pyrogenicity), sensitization (priming, idiosyncratic reactions) and impairment of immune responses (anergy, immunosuppression). We have previously studied a human whole blood system which allows the study of the release of inflammatory cytokines in response to a variety of stimuli. This model allows the assessment of this basic immune mechanism without preparation artefacts and relatively small interindividual variances. We have used this model previously to assess pyrogens, namely type (1) immunotoxic reactions. The model also proved to be suitable for immunopharmacological studies in vitro as well as ex vivo. Here, we studied the suitability of the test system to study type (3) immunotoxic effects. In order to also allow ex vivo studies, we have transferred the system to murine blood. This report summarizes our own use of this model with special emphasis on immunotoxicological studies. Our own listed bibliography gives access to the variety of applications of the human whole blood model since its introduction in 1982.

The use of genetically engineered cells for assessing CYP2D6-related polymorphic effects

As an example of advanced testing in the field of metabolism in an industrial environment, the introduction of some novel approaches, including the use of genetically engineered cell lines for assessing CYP 2D6-related polymorphic effects is illustrated. In this paper, it is demonstrated that novel in vitro test systems can be developed by using these genetically engineered cell lines for evaluating the potential risks associated with proprietary drugs (especially if their metabolism depends to a high extent on CYP 2D6). Moreover, it is demonstrated that, by the use of these in vitro methods, issues such as polymorphism, for which no animal models are available, can be assessed in such a way that predictions can be made on adverse effects which, up to now, could only be detected during clinical trials. Through the use of these new biotechnological in vitro metabolism models, clinically relevant data can be obtained for a scientifically-based human risk assessment, and animal use can be reduced.