Do GC/MS methods available for furan and alkylfurans in food provide comparable results? - An interlaboratory study and safety assessment of 2-pentylfuran in food

A call for data on the occurrence of alkylfurans in food and feed from EFSA triggered the development of new methods to cover next to furan also 2- and 3-methylfuran, 2,5-dimethyl- and 2-ethylfuran as well as 2-pentylfuran. A significant variability was noticed when comparing analysis of 2-pentylfuran and furans in the same matrix performed by different laboratories. To assess the variability an interlaboratory study including eight laboratories was organised. The highest variabilities were observed when analysing cereals, with measurements of 2-pentylfuran indicating concentrations from 8 mg/kg up to more than 1000 mg/kg in the same sample. This study illustrates that the analysis of 2-pentylfuran requires special attention, and that additional method development would be necessary to ensure reliable and reproducible determination of 2-pentylfuran at contamination level. Moreover, a recent evaluation of the EFSA Panel on Food Additives and Flavourings indicates that concerns for genotoxicity, reason why it was grouped with the shorter alkylfurans, are now ruled out. We question the need and justification to include 2-pentylfuran in the analytical method as requested by EFSA, from both the analytical and the safety perspective.

Coupling the H295R and ERα and AR U2OS CALUX assays enables simultaneous testing for estrogenic, anti-androgenic and steroidogenic modalities

Endocrine active substances, including steroidogenesis modulators, have received increased attention. The in vitro H295R steroidogenesis assay (OECD TG 456) is commonly used to test for this modality. However, current detection methods often fail to capture alterations to estrogen biosynthesis. The present study explored the potential of ERα and AR CALUX bioassays to serve as a detection system for the original H295R assay, as they can quantify lower hormone concentrations and can simultaneously provide information about estrogen- and androgen- receptor activities. Using substances from the original OECD validation study, we obtained lowest observed effect concentrations for steroidogenesis mostly equivalent to those previously reported and sometimes lower for estrogen biosynthesis. However, categorization of many of these substances as receptor (ant)agonists or disruptors of steroidogenesis was difficult because often substances had both modalities, including some where the receptor-mediated activities were identified at concentrations below those triggering steroidogenic effects. When the leading activity was not accounted for, H295R-CALUX assay sensitivity in comparison to the OECD validation study was 0.50 for androgen and 0.78 for estrogen biosynthesis. However, upon reinterpretation of the combined assay results to identify endocrine activities without regard to the modality or direction of effects, assay sensitivity was equal to 1.00. These proof-of-concept study findings indicate the high relevance of this assay for the identification of endocrine active substances with additional valuable mode-of-action information and the capacity to detect smaller changes in estrogen biosynthesis, suggesting that the coupled H295R-CALUX assay has promise for the analysis of samples in a decision-making context.

Incorporation of Metabolic Activation in the HPTLC-SOS-Umu-C Bioassay to Detect Low Levels of Genotoxic Chemicals in Food Contact Materials

The safety evaluation of food contact materials requires excluding mutagenicity and genotoxicity in migrates. Testing the migrates using in vitro bioassays has been proposed to address this challenge. To be fit for that purpose, bioassays must be capable of detecting very low, safety relevant concentrations of DNA-damaging substances. There is currently no bioassay compatible with such qualifications. High-performance thin-layer chromatography (HPTLC), coupled with the planar SOS Umu-C (p-Umu-C) bioassay, was suggested as a promising rapid test (~6 h) to detect the presence of low levels of mutagens/genotoxins in complex mixtures. The current study aimed at incorporating metabolic activation in this assay and testing it with a set of standard mutagens (4-nitroquinoline-N-oxide, aflatoxin B1, mitomycin C, benzo(a)pyrene, N-ethyl nitrourea, 2-nitrofluorene, 7,12-dimethylbenzanthracene, 2-aminoanthracene and methyl methanesulfonate). An effective bioactivation protocol was developed. All tested mutagens could be detected at low concentrations (0.016 to 230 ng/band, according to substances). The calculated limits of biological detection were found to be up to 1400-fold lower than those obtained with the Ames assay. These limits are lower than the values calculated to ensure a negligeable carcinogenic risk of 10^-5. They are all compatible with the threshold of toxicological concern for chemicals with alerts for mutagenicity (150 ng/person). They cannot be achieved by any other currently available test procedures. The p-Umu-C bioassay may become instrumental in the genotoxicity testing of complex mixtures such as food packaging, foods, and environmental samples.

POS1020 BIOLOGICAL DMARD TREATMENT IN PSORIATIC ARTHRITIS IS LIKEWISE EFFECTIVE IN PATIENTS WITH HIGH AND WITH LOW JOINT COUNTS – RESULTS FROM THE SWISS CLINICAL QUALITY MANAGEMENT (SCQM) FOR RHEUMATIC DISEASES COHORT STUDY

Background

Biological and targeted synthetic (b/tsDMARDs) may be used in absent remission in psoriatic arthritis (PsA) independent of a defined number of affected joints. However, minimum three swollen and three tender joints are a common inclusion criterion in trials of b/tsDMARDs, and less is currently known about their effectiveness in PsA patients with low joint counts.

Objectives

To characterize PsA patients with low or high joint counts (LJC/HJC), analyze their drug treatment in routine care, and estimate the effectiveness of a first bDMARD in LJC and HJC patients.

Methods

We defined patients with less than three tender or swollen joints as LJC, and those with at least three tender and swollen joints as HJC patients. Patients were twice categorized according to their joint counts at registration in the registry, and at start of a first bDMARD (Table 1). We compared HJC and LJC at registration for current and future DMARD therapies, and at start of a first bDMARD for treatment effectiveness, using drug retention in univariate and in multivariable Cox regression models.

Table 1.

Selected characteristics of bDMARD naïve PsA patients with a low and with a high number of affected joints at start of their first bDMARD.

VariableLevelsHJC% highLJC% lowN allpbDMARD typeTNFi17692.617588.8351=0.22OMA147.42211.236csDMARD cotherapyyes11761.69045.7207<0.01csDMARD historynaive2312.15527.978<0.01tsDMARD_historynaive17592.117789.8352=0.47Dactylitis historyyes11560.56030.5175<0.01HLA B27yes1211.52823.340=0.02MDAYes00.0178.617<0.01DAPSA remission00.0126.112<0.01DactylitisYes9349.03316.8126<0.01EnthesitisYes6361.85547.0118=0.03BMImean (SD)27.65(5.05)26.58(4.72)333=0.046MASESmean (SD)2.86(3.93)1.61(2.47)219=0.005HAQ-DImean (SD)0.77(0.58)0.60(0.50)292=0.010EQ-5dmean (SD)62.22(20.63)67.22(16.27)294=0.022Patient globalmean (SD)5.93(2.41)4.83(2.58)288<0.001Tender joint countmean (SD)10.15(8.93)4.92(8.17)387<0.001Swollen joint countmean (SD)7.16(4.91)1.37(2.15)387<0.001Patient painmean (SD)5.96(2.47)4.85(2.51)290<0.001

Abbreviations: DAPSA: Disease activity of PsA. BMI: Body mass index, EQ-5d: European Quality of Life Measurement in five dimensions. HAQ-DI. Health assessment questionnaire disability index. HJC: High joint count, LJC: Low joint count, MASES: Maastricht ankylosing spondylitis enthesitis score, MDA: minimal disease activity, OMA: other mode of action than TNFi.

Results

We followed DMARD therapies for median (IQR) 3.2 (1.6, 5.0) in 675 LJC patients and for 3.4 (1.8, 5.2) years in 334 HJC patients. LJC patients at registration as well as at start of a first bDMARD were less often female, with less severe skin, enthesitis, dactylitis and nail involvement. Furthermore, LJC patients had lower disability indices and a more favorable health related quality of life. When defined at registration, LJC were as frequent as HJC patients on csDMARDs, but less often on bDMARDs. During their follow-up, a csDMARD, a first and a second bDMARD were less often and on average later commenced in LJC than in HJC patients. However, when defined at start of a first bDMARD, drug retention did not significantly differ between LJC and HJC patients (Figure 1).

Figure 1.

Multivariable adjusted Cox regression model for discontinuation of a first bDMARD. Abbreviation: JC_group_base: Low and high joint count groups at baseline.

Conclusion

The majority of Swiss PsA patients is in LJC status, which also means a better status in most PsA domains than in HJC patients. LJC status was associated with established bDMARD therapy and with slower treatment escalation. However, bDMARDs were likewise effective in bDMARD-naïve LJC and HJC patients, and should not withhold only for reasons of a low joint count.

References

[1]Gossec et al. 2020, Annals of the Rheumatic Diseases 79 (6): S700–712.

[2]Gladman et al. 2021, The Journal of Rheumatology 48 (12): 1824–29.

Acknowledgements

I acknowledge all patients, physicians and researchers of the Swiss Clinical Quality Management (SCQM) for rheumatic diseases Program, and Celgene for funding of this research.

Disclosure of Interests

Burkhard Moeller Speakers bureau: Novartis, MSD, Synergy, Eli Lilly, Bristol-Myers-Squibb, Janssen-Cilag, AbbVie and Pfizer, Grant/research support from: Celgene, Amgen, Vifor, Adrian Ciurea Speakers bureau: Abbvie and Novartis, Raphael Micheroli: None declared, Michael J. Nissen Speakers bureau: Abbvie, Celgene, Eli-Lilly, Janssen, Novartis and Pfizer, Eleftherios Papagiannoulis: None declared, Almut Scherer: None declared, Godehard Scholz: None declared, Nikhil Yawalkar Speakers bureau: Abbvie, Amgen, Celgene, Janssen, Lilly, Novartis, Pfizer

Limitations of currently available in vitro oestrogenicity bioassays for effect-based testing of whole foods as the basis for decision making

The idea that previously unknown hazards can be readily revealed in complex mixtures such as foods is a seductive one, giving rise to the hope that data from effect-based assays of food products collected in market surveys is of suitable quality to be the basis for data-driven decision-making. To study this, we undertook a comparative study of the oestrogenicity of blinded cereal samples, both in a number of external testing laboratories and in our own facility. The results clearly showed little variance in the activities of 9 samples when using a single method, but great differences between the activities from each method. Further exploration of these findings suggest that the oestrogenic activity is likely an inherent part of the natural food matrix which the varying sample preparation methods are able to release and extract to differing degrees. These issues indicate the current poor suitability of these types of datasets to be used as the basis for consumer advice or food decision-making. Data quality must be improved before such testing is used in practice.

OP0061 A PROOF-OF-CONCEPT STUDY TO ASSESS THE EFFICACY OF TOCILIZUMAB MONOTHERAPY AFTER ULTRA-SHORT GLUCOCORTICOID ADMINISTRATION TO TREAT GIANT CELL ARTERITIS - THE GUSTO TRIAL

Background:

Two randomised controlled trials [1, 2] demonstrated a glucocorticoid (GC)-sparing effect of tocilizumab (TCZ) of at least 50%. Long-term GC treatment leads invariably to numerous side effects, particularly in elderly giant cell arteritis (GCA) patients.

Objectives:

The GUSTO (GCA treatment with ultra-short GC and TCZ) trial was set up to evaluate the efficacy and safety of TCZ-monotherapy after ultra-short GC treatment in new-onset GCA.

Methods:

Eighteen patients with newly diagnosed GCA were enrolled in this investigator-initiated, single-arm, single-center, open-label clinical trial with Simon’s two stage design (NCT03745586). Patients received 500 mg methylprednisolone intravenously for 3 consecutive days. Thereafter, GC treatment was discontinued and TCZ (8 mg/kg body-weight) was administered intravenously, followed by weekly subcutaneous TCZ injections (162 mg) from day 10 until week 52. The primary endpoint was defined as the proportion of patients who achieved remission within 31 days and showed no relapse at week 24; the secondary endpoint included the proportion of patients with complete relapse-free remission of disease at week 52. Remission was defined as disappearance of GCA symptoms, whereas partial remission included the presence of mild symptoms (defined as non-ischemic with NRS<5/10, reported as mild, not occurring on most days of the week). An interim analysis of the primary endpoint was performed after the first 12 patients reached the primary endpoint.

Results:

At baseline there were 12/18 female patients, and the median age was 71 (range 64-78) years. Overall, 15/18 had cranial symptoms (10/18 had jaw claudication, 6/18 had visual symptoms), 10/18 suffered from polymyalgia rheumatica (PMR)-symptoms, 16/18 had positive cranial ultrasound, and 13/18 had positive histopathology.

At interim analysis, only 25% (3/12) of patients achieved remission within 31 days and stayed relapse-free up to week 24. Thus, the null hypothesis that the proportion of responders would be smaller than 40% (p=0.92) was not rejected. Of the 18 patients recruited at the time of interim analysis, 14 achieved remission within 24 weeks (mean duration 11.1 (95% CI 8.3-13.9) weeks) and 13 showed no relapses up to 52 weeks (72%, 95% CI 47-90%). Overall, 3/18 patients were non-responders (2/3 with persistent cranial symptoms including one new-onset of an anterior ischemic optic neuropathy (AION); 1/3 with persistent PMR symptoms) and started on rescue GC-treatment, and 2/18 discontinued the study due to an adverse event (hepatopathy and diverticulitis, respectively; 1/2 after induction of remission).

Figure 1 demonstrates remission status over time.

Conclusion:

After a 3-days pulse of methylprednisolone, ensuing TCZ monotherapy induced and maintained remission until week 52 in 13/18 patients. The data add an important piece of evidence regarding the potency of blocking the interleukin-6 pathway in GCA and suggest that a substantial reduction of concomitant GC treatment in TCZ-treated GCA patients is feasible.

References:

[1]Villiger, P.M., et al., Tocilizumab for induction and maintenance of remission in giant cell arteritis: a phase 2, randomised, double-blind, placebo-controlled trial. Lancet, 2016. 387(10031): p. 1921-7.

[2]Stone, J.H., et al., Trial of Tocilizumab in Giant-Cell Arteritis. N Engl J Med, 2017. 377(4): p. 317-328.

Figure 1.

Disease status of patients at each visit (Day 10 - week 52, n=18).

Disclosure of Interests:

Lisa Christ Shareholder of: F. Hoffmann-La Roche, Grant/research support from: Gilead Sciences; F. Hoffmann-La Roche; Pfizer, Luca Seitz: None declared, Godehard Scholz: None declared, Adela-Cristina Sarbu: None declared, Jennifer Amsler: None declared, Lukas Bütikofer: None declared, Christoph Tappeiner: None declared, Florian Kollert Shareholder of: Roche, Consultant of: Yes (Actelion, BMS, Boehringer-Ingelheim, Pfizer), Grant/research support from: Yes (Gilead, Pfizer), Employee of: Yes, I am currently employed by Roche and previously by Novartis, Stephan Reichenbach: None declared, Peter Villiger Speakers bureau: Roche, MSD, Abbvie, Pfizer, Novartis, Grünenthal, Celgene, Sanofi, Chugai, Consultant of: Roche, MSD, Abbvie, Pfizer, Novartis, Celgene, Sanofi, Grant/research support from: Roche, MSD, Abbvie

OP0149 VISUAL LOSS IN PATIENTS WITH GIANT CELL ARTERITIS TREATED WITH TOCILIZUMAB

Background:

Whether Tocilizumab (TCZ) may prevent vision loss in Giant Cell Arteritis (GCA) to the same extent as glucocorticoids remains a key and unanswered question. A patient cohort observed over up to 8 years addresses this issue.

Objectives:

To investigate the frequency of vision loss/visual impariment in a GCA cohort treated with TCZ.

Methods:

In this observational monocentric study, the courses of 192 patients with GCA treated with TCZ between 01.01.2011 and 31.12.2018 were analyzed. Data were extracted from medical records and collected in a Clinical Trial Unit (CTU) - based registry. Demographic, clinical and laboratory data were analyzed.

Results:

192 patients with GCA were treated with TCZ; 121 (63%) were female, 112 (58%) fulfilled 1990 American College of Rheumatology (ACR) criteria, all others had large vessel vasculitis based on magnetic resonance-angiography (MRA). The cumulative duration of TCZ treatment was 3467 months; the median treatment duration was 13.8 (8.5; 22.8) months. At baseline, visual impairment was present in 71 (37%) and vision loss in 21 (7.8%) patients. Visual loss was associated with higher age (74 (70; 82) vs. 70 (63; 76) years; p=0.029), lower C-reactive protein at baseline (14.0 (3.5; 42.0) vs. 54.5 (21.0; 101.0) mg/l; p<0.001), cranial symptoms (p<0.0001), jaw claudication (p=0.030) and negative MRA of the aorta (p=0.020). Over the observed time span only one patient taking part in a clinical trial developed vision loss. In total 4 (2%) patients with vision impairment showed deterioration and 61 (32%) improvement.

Conclusion:

Collectively, our data suggest that TCZ is able to prevent visual loss and may have a favorable effect on visual impairment.

Disclosure of Interests:

Jennifer Amsler: None declared, Iveta Kysela: None declared, Lisa Christ Consultant of: BMS, Christoph Tappeiner: None declared, Luca Seitz: None declared, Godehard Scholz: None declared, Florian Kollert Employee of: Novartis, Stephan Reichenbach: None declared, Peter Villiger Consultant of: MSD, Abbvie, Roche, Pfizer, Sanofi, Speakers bureau: Roche, MSD, Pfizer

New 2D layered structures with direct fluorine–metal bonds: MF(CH3COO) (M: Sr, Ba, Pb)

New coordination polymers with 2D network structures with fluorine directly coordinated to the metal ion were prepared both via mechanochemical synthesis and fluorolytic sol–gel synthesis.

Exposure assessment of process-related contaminants in food by biomarker monitoring

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario's and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.

[Tapering and termination of immunosuppressive treatment in spondyloarthritides (including psoriatic arthritis)]

BACKGROUND

Immunomodulatory long-term treatment has also become the standard treatment for spondyloarthritides (SpA), including psoriatic arthritis (PsA); however, uncertainty exists about dose reduction or termination of treatment after remission or low disease activity.

OBJECTIVE

When is it possible to reduce medication or terminate treatment for SpA?

MATERIAL AND METHODS

An extensive non-systematic literature search was performed focusing on practice guidelines, systematic meta-analyses and clinical trials on medicinal long-term treatment and voluntary medication reduction in axial and peripheral SpA, including PsA.

RESULTS

The chances of drug-free remission after treatment with biologics for axial SpA and in PsA are low; however, in remission or a state of low disease activity reduction of the cumulative dosage of biologics can be successful in 53-100% of cases without a significant increase in disease activity. The current state and duration of remission, with or without comedication with nonsteroidal anti-inflammatory drugs (NSAID), extra-articular disease manifestations and the results of previous treatment attempts have to be carefully taken into consideration before elective dose reduction.

CONCLUSION

Reduction of long-term treatment is an individualized decision made jointly by patients and physicians. The risk of flares and especially of extra-articular disease manifestations needs to be weighed against the possible advantages of reduced medication. Maintainenance of mediction-free disease remission is too rare in SpA or PsA patients carefully selected for biologics treatment, to allow a later voluntary termination of therapy, without at least a prior cautious attempt at dose reduction.

Evaluation of Interindividual Human Variation in Bioactivation and DNA Adduct Formation of Estragole in Liver Predicted by Physiologically Based Kinetic/Dynamic and Monte Carlo Modeling

Estragole is a known hepatocarcinogen in rodents at high doses following metabolic conversion to the DNA-reactive metabolite 1'-sulfooxyestragole. The aim of the present study was to model possible levels of DNA adduct formation in (individual) humans upon exposure to estragole. This was done by extending a previously defined PBK model for estragole in humans to include (i) new data on interindividual variation in the kinetics for the major PBK model parameters influencing the formation of 1'-sulfooxyestragole, (ii) an equation describing the relationship between 1'-sulfooxyestragole and DNA adduct formation, (iii) Monte Carlo modeling to simulate interindividual human variation in DNA adduct formation in the population, and (iv) a comparison of the predictions made to human data on DNA adduct formation for the related alkenylbenzene methyleugenol. Adequate model predictions could be made, with the predicted DNA adduct levels at the estimated daily intake of estragole of 0.01 mg/kg bw ranging between 1.6 and 8.8 adducts in 10(8) nucleotides (nts) (50th and 99th percentiles, respectively). This is somewhat lower than values reported in the literature for the related alkenylbenzene methyleugenol in surgical human liver samples. The predicted levels seem to be below DNA adduct levels that are linked with tumor formation by alkenylbenzenes in rodents, which were estimated to amount to 188-500 adducts per 10(8) nts at the BMD10 values of estragole and methyleugenol. Although this does not seem to point to a significant health concern for human dietary exposure, drawing firm conclusions may have to await further validation of the model's predictions.

Nanoscopic yttrium oxide fluorides: non-aqueous fluorolytic sol-gel synthesis and structural insights by 19F and 89Y MAS NMR

Nanoscopic yttrium acetate fluorides Y(CH(3)COO)(3-z)F(z) and yttrium oxide fluorides YO(3-z)/(2)F(z )were prepared with tunable Y/F molar ratios via the fluorolytic sol-gel route. All samples were characterized by X-ray diffraction, elemental analysis and thermal analysis. In addition, local structures of all samples were studied by (19)F MAS, (19)F-(89)Y CP MAS and (1)H-(89)Y CP MAS NMR spectroscopy and the respective chemical shifts are given. For both classes of compounds, only the fluorination using one equivalent of F (z = 1) leads to defined, well crystalline matrices: yttrium acetate fluoride Y(CH(3)COO)(2)F and r-YOF.

[Vestibular dysfunction after cochlear implant in adults]

BACKGROUND

According to the literature, clinical vertigo after cochlear implant (CI) occurs in 0.33-75%, a peripheral vestibular loss of function in 20-75%.

MATERIALS AND METHODS

Between 2006 and 2009, 30 adults were implanted with a 22-channel Nucleus Freedom CI (41 operations). Cochleostomy was performed anterocaudal of the round window and the electrode inserted using the "off-stylet" technique into the scala tympani.

RESULTS

Clinical vertigo occurred after 10/41 (24.4%) operations: acutely in 5/41 (12.2%), continuous in 1/41 (2.4%), delayed for 6-18 months in 5/41 (12.2%). In the calorimetry, 3/27 (11.1%) vestibular organs displayed a loss of function (p = 0.16). Three of 8 patients (37.5%) with clinical vertigo after surgery showed a loss of vestibular function (p = 0.08).

CONCLUSION

Using the described techniques and materials, the risk of loss of vestibular function and the incidence of clinical vertigo can be minimized. Postoperative vertigo did not occur more often in patients with preoperative diminished vestibular function than in patients with normal findings. Therefore, preoperative vestibular function tests cannot be an indicator for the frequency of vertigo after CI. If one vestibular organ shows preoperative dysfunction, the non-affected normal vestibular organ should not be implanted.

Prevalidation of the Embryonic Stem Cell Test (EST)-A New In Vitro Embryotoxicity Test

Pluripotent embryonic stem cells (ES cells) of the mouse (cell-line D3) can be maintained in the undifferentiated state in the presence of LIF (Leukaemia Inhibitory Factor). Upon withdrawal of LIF, these cells differentiate into various cell types under appropriate conditions. This property of ES cells allowed us to develop an in vitro embryotoxicity test, the Embryonic Stem Cell Test (EST; In Vitro Toxicology 1997, 10, 119-127), which does not require taking embryonic cells or tissues from pregnant animals. In the EST, the effect of test chemicals on three endpoints is assessed: inhibition of the differentiation of ES cells into contracting myocard, cytotoxicity in ES cells and cytotoxicity in mouse 3T3 fibroblasts, which are serving as differentiated cells in the test. The results of a prevalidation study of the EST are described, which was conducted according to the ECVAM prevalidation scheme. In the first stage of the study (Phase I), a standard operating procedure (SOP) was elaborated. In the second phase (Phase II), the interlaboratory transferability of the EST was assessed using three test chemicals representing three classes of embryotoxicity (a strong, a weak and a non-embryotoxic chemical) in two European laboratories (ZEBET at the BgVV in Berlin, Germany; ECVAM at the JRC in Ispra, Italy) and one US laboratory (Institute for In Vitro Sciences (IIVS) in Gaithersburgh, MA, USA). In the final stage of prevalidation (Phase III), nine test chemicals and a positive control were tested under blind conditions at ZEBET and ECVAM. The statistical evaluation of the results led to the development of an improved prediction model for the EST.

Analytical approaches for MCPD esters and glycidyl esters in food and biological samples: a review and future perspectives

Esters of 2 - and 3-monochloropropane-1,2-diol (MCPD) and glycidol esters are important contaminants of processed edible oils used as foods or food ingredients. This review describes the occurrence and analysis of MCPD esters and glycidol esters in vegetable oils and some other foods. The focus is on the analytical methods based on both direct and indirect methods. Methods of analysis applied to oils and lipid extracts of foods have been based on transesterification to free MCPD and determination by gas chromatography-mass spectrometry (indirect methods) and by high-performance liquid chromatography-mass spectrometry (direct methods). The evolution and performance of the different methods is described and their advantages and disadvantages are discussed. The application of direct and indirect methods to the analysis of foods and to research studies is described. The metabolism and fate of MCPD esters and glycidol esters in biological systems and the methods used to study these in body tissues studies are described. A clear understanding of the chemistry of the methods is important when choosing those suitable for the desired application, and will contribute to the mitigation of these contaminants.

Quantitative comparison between in vivo DNA adduct formation from exposure to selected DNA-reactive carcinogens, natural background levels of DNA adduct formation and tumour incidence in rodent bioassays

This study aimed at quantitatively comparing the occurrence/formation of DNA adducts with the carcinogenicity induced by a selection of DNA-reactive genotoxic carcinogens. Contrary to previous efforts, we used a very uniform set of data, limited to in vivo rat liver studies in order to investigate whether a correlation can be obtained, using a benchmark dose (BMD) approach. Dose-response data on both carcinogenicity and in vivo DNA adduct formation were available for six compounds, i.e. 2-acetylaminofluorene, aflatoxin B1, methyleugenol, safrole, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and tamoxifen. BMD(10) values for liver carcinogenicity were calculated using the US Environmental Protection Agency BMD software. DNA adduct levels at this dose were extrapolated assuming linearity of the DNA adduct dose response. In addition, the levels of DNA adducts at the BMD(10) were compared to available data on endogenous background DNA damage in the target organ. Although for an individual carcinogen the tumour response increases when adduct levels increase, our results demonstrate that when comparing different carcinogens, no quantitative correlation exists between the level of DNA adduct formation and carcinogenicity. These data confirm that the quantity of DNA adducts formed by a DNA-reactive compound is not a carcinogenicity predictor but that other factors such as type of adduct and mutagenic potential may be equally relevant. Moreover, comparison to background DNA damage supports the notion that the mere occurrence of DNA adducts above or below the level of endogenous DNA damage is neither correlated to development of cancer. These data strongly emphasise the need to apply the mode of action framework to understand the contribution of other biological effect markers playing a role in carcinogenicity.

A review on the beneficial aspects of food processing

The manuscript reviews beneficial aspects of food processing with main focus on cooking/heat treatment, including other food-processing techniques (e.g. fermentation). Benefits of thermal processing include inactivation of food-borne pathogens, natural toxins or other detrimental constituents, prolongation of shelf-life, improved digestibility and bioavailability of nutrients, improved palatability, taste, texture and flavour and enhanced functional properties, including augmented antioxidants and other defense reactivity or increased antimicrobial effectiveness. Thermal processing can bring some unintentional undesired consequences, such as losses of certain nutrients, formation of toxic compounds (acrylamide, furan or acrolein), or of compounds with negative effects on flavour perception, texture or colour. Heat treatment of foods needs to be optimized in order to promote beneficial effects and to counteract, to the best possible, undesired effects. This may be achieved more effectively/sustainably by consistent fine-tuning of technological processes rather than within ordinary household cooking conditions. The most important identified points for further study are information on processed foods to be considered in epidemiological work, databases should be built to estimate the intake of compounds from processed foods, translation of in-vitro results to in-vivo relevance for human health should be worked on, thermal and non-thermal processes should be optimized by application of kinetic principles.

Glycolaldehyde-modified β-lactoglobulin AGEs are unable to stimulate inflammatory signaling pathways in RAGE-expressing human cell lines

SCOPE

Advanced glycation endproducts (AGEs) are suspected to stimulate inflammatory signaling pathways in target tissues via activation of the receptor for AGEs. Endotoxins are generally recognized as potential contamination of AGE preparations and stimulate biological actions that are very similar as or identical to those induced by AGEs.

METHODS AND RESULTS

In our study, we used glycolaldehyde-modified β-lactoglobulin preparations as model AGEs and employed two methods to remove endotoxin using either affinity columns or extraction with Triton X-114 (TX-114). Affinity column-purified AGEs retained their ability to stimulate inflammatory signaling as measured by mRNA expression of inflammatory cytokines in the human lung epithelial cell line Beas2b. However, glycolaldehyde-modified AGEs purified by extraction with TX-114 did not show any stimulation of mRNA expression of inflammatory cytokines. The presence of a cell stimulating endotoxin-like activity was demonstrated in the detergent phase after extraction with TX-114, thus indicating that not AGEs but a lipophilic contamination was responsible for the stimulation of inflammatory signaling.

CONCLUSION

Our results demonstrate that glycolaldehyde-modified AGEs are unable to induce inflammatory signaling in receptor for AGE-expressing cells. The observed cell-activating activity can be ascribed to an endotoxin-like lipophilic contamination present in AGE preparations and affinity column purification was insufficient to remove this contamination.

Use of physiologically based biokinetic (PBBK) modeling to study estragole bioactivation and detoxification in humans as compared with male rats

The extent of bioactivation of the herbal constituent estragole to its ultimate carcinogenic metabolite 1′-sulfooxyestragole depends on the relative levels of bioactivation and detoxification pathways. The present study investigated the kinetics of the metabolic reactions of both estragole and its proximate carcinogenic metabolite 1′-hydroxyestragole in humans in incubations with relevant tissue fractions. Based on the kinetic data obtained a physiologically based biokinetic (PBBK) model for estragole in human was defined to predict the relative extent of bioactivation and detoxification at different dose levels of estragole. The outcomes of the model were subsequently compared with those previously predicted by a PBBK model for estragole in male rat to evaluate the occurrence of species differences in metabolic activation. The results obtained reveal that formation of 1′-oxoestragole, which represents a minor metabolic route for 1′-hydroxyestragole in rat, is the main detoxification pathway of 1′-hydroxyestragole in humans. Due to a high level of this 1′-hydroxyestragole oxidation pathway in human liver, the predicted species differences in formation of 1′-sulfooxyestragole remain relatively low, with the predicted formation of 1′-sulfooxyestragole being twofold higher in human compared with male rat, even though the formation of its precursor 1′-hydroxyestragole was predicted to be fourfold higher in human. Overall, it is concluded that in spite of significant differences in the relative extent of different metabolic pathways between human and male rat there is a minor influence of species differences on the ultimate overall bioactivation of estragole to 1′-sulfooxyestragole.