EFSA scientific advice to EC on new scientific information in relation to the risk assessment of genetically modified organisms

Transcription

1 TECHNICAL REPORT APPROVED: 29 October 2015 PUBLISHED: 03 November 2015 Abstract EFSA scientific advice to EC on new scientific information in relation to the risk assessment of genetically modified organisms European Food Safety Authority Following a request of the European Commission, the European Food Safety Authority (EFSA) reviewed a recent publication by Ayyadurai and Deonikar, 2015 (Do GMOs Accumulate Formaldehyde and Disrupt Molecular Systems Equilibria? Systems Biology May Provide Answers). The main arguments presented by the authors were the significant accumulation of formaldehyde and concomitant depletion of glutathione in Roundup Ready soybeans due to the genetic modification when applying computational model simulation of important biological pathways. EFSA considers that the applied computer model is exclusively based on theoretical considerations, and that no empirical evidence is provided to support the model predictions. EFSA addressed one-by-one the technical issues involved, related to the model chosen, the lack of empirical data, and accumulation of formaldehyde and concomitant depletion of glutathione. Considering that the authors do not provide information on the input data and the algorithm used in the model, that the model is not validated, and that no empirical studies have been presented to support the predictions of the model, EFSA is of the opinion that the author s conclusions are not supported. Therefore, EFSA considers that its previous risk assessment conclusions on EPSPSexpressing herbicide tolerant GM soybean events remain valid. European Food Safety Authority, 2015 Key words: soybean, Roundup Ready, formaldehyde, glutathione. Requestor: The European Commission Question number: EFSA-Q Correspondence: gmo@efsa.europa.eu EFSA Supporting publication 2015:EN-885

2 Acknowledgements: EFSA wishes to thank its staff: Hermann Broll, Franco Maria Neri and Claudia Paoletti for the preparation of this technical report. Suggested citation: EFSA (European Food Safety Authority), EFSA scientific advice to EC on new scientific information in relation to the risk assessment of genetically modified organisms. EFSA supporting publication 2015:EN pp. European Food Safety Authority, 2015 Reproduction is authorised provided the source is acknowledged. 2 EFSA Supporting publication 2015:EN-885

3 Summary This technical report is the response to a mandate from the European Commission (EC) to evaluate scientific issues raised by a recent publication by Ayyadurai and Deonikar (2015) 1. By applying systems biology and using a computational model, the authors predicted that a significant accumulation of formaldehyde and concomitant depletion of glutathione might occur in Roundup Ready soybeans due to the genetic modification. The study described in the publication is exclusively based on theoretical considerations and on the use of a combination of literature search together with computational modelling of the C1 metabolism pathway and oxidative stress. EFSA addressed one-by-one the technical issues involved, related to the model chosen, the lack of empirical data, and accumulation of formaldehyde and concomitant depletion of glutathione. Considering that the authors do not provide information on the input data and the algorithm used in the model, that the model is not validated, and that no empirical studies have been presented to support the predictions of the model, EFSA is of the opinion that the author s conclusions are not supported. Therefore, EFSA considers that its previous risk assessment conclusions on EPSPSexpressing herbicide tolerant GM soybean events remain valid. 1 Ayyadurai, V.A.S. and Deonikar, P Do GMOs accumulate formaldehyde and disrupt molecular systems equilibria? Systems biology may provide answers. Agricultural Sciences, 6, EFSA Supporting publication 2015:EN-885

4 Table of contents Abstract...1 Summary Introduction Background and Terms of Reference as provided by the requestor Data and Methodologies Data Methodologies Assessment Summary of the publication Background Evaluation of the study performed and the conclusions made by the authors Conclusions...7 Documentation provided to EFSA...8 References...8 Abbreviations EFSA Supporting publication 2015:EN-885

5 1. Introduction 1.1. Background and Terms of Reference as provided by the requestor The EC mandate to analyse the publication made by Ayyadurai and Deonikar (2015) was received on 4 August 2015 (Ayyadurai and Deonikar, 2015). The timeline for receiving EFSA s reply was originally indicated as mid-september 2015, and upon agreement extended to 31 October EFSA was mandated 2 by the EC to evaluate scientific issues raised by a recent publication by Ayyadurai and Deonikar (2015) and whether or not the new scientific report will lead to reconsider the outcome of its previous opinions for GMOs. By using a computational systems biology model, the authors predicted that a significant accumulation of formaldehyde and concomitant depletion of glutathione might occur in Roundup Ready soybeans due to the genetic modification. The study described in the publication is based on theoretical considerations and the use of a combination of literature search together with a computer model of the C1 metabolism pathway and oxidative stress. This technical report is the response to a mandate from the European Commission (EC) 2. Data and Methodologies 2.1. Data In delivering this technical report, EFSA considered the data and conclusions reported in the scientific publication by Ayyadurai and Deonikar (2015) 3 along with data in all EPSPS-expressing herbicide tolerant soybean events for which the EFSA GMO panel has already issued a scientific opinion (Table 1). Table 1: Overview of GM soybean applications expressing EPSPS protein conferring herbicide tolerance to glyphosate previously assessed by the EFSA GMO Panel GM Plant Application Event Scope Reference EFSA-GMO-RX Soybean Import/Processing EFSA (2010) (8.1b_20.1b) (8.1a and 20.1a) EFSA-GMO-NL Soybean Import/Processing EFSA (2012a) EFSA-GMO-NL MON Soybean Import/Processing EFSA (2008) EFSA-GMO-UK Soybean Import/Processing EFSA (2011b) EFSA-GMO-NL MON x MON Import/Processing EFSA (2012c) Soybean EFSA-GMO-NL MON Soybean Import/Processing EFSA (2012b) EFSA-GMO-NL MON x MON Import/Processing EFSA (2015a) Soybean EFSA-GMO-BE FG72 Soybean Import/Processing EFSA (2015b) EFSA-GMO-NL MON x MON Soybean Import/Processing EFSA (2015c) EFSA-GMO-NL MON x MON Soybean Import/Processing EFSA (2015d) 2 Mandate M (Question number EFSA-Q ) 5 EFSA Supporting publication 2015:EN-885

6 2.2. Methodologies EFSA took into account the appropriate principles described in its guidelines for the food and feed risk assessment of GM plants (EFSA, 2006, 2011a). 3. Assessment 3.1. Summary of the publication In the publication Do GMOs Accumulate Formaldehyde and Disrupt Molecular Systems Equilibria? Systems Biology May Provide Answers, V. A. Shiva Ayyadurai and Prabhakar Deonikar (2015) describe the application of systems biology for safety evaluations of genetically modified organisms (GMO). The authors used a computational system biology approach, integrating models for C1 metabolism and oxidative stress in soybean. The results of the computer simulations predict a significant accumulation of formaldehyde and a concomitant depletion of glutathione in the GM soybean, with a potential negative impact on health and safety Background The EFSA assessment described below considers the three main aspects mentioned in the publication by Ayyadurai and Deonikar (2015): (a) the increased levels of formaldehyde, (b) decreased glutathione levels in GM soybeans and (c) the C1 metabolism used in the computer model. (a) Formaldehyde is a naturally-occurring organic compound with the formula CH 2 O. In view of its widespread use, toxicity, and volatility, formaldehyde is of great relevance for human and animal health. Formaldehyde is ubiquitously present in living organisms. Formaldehyde exposure also has endogenous sources it is produced in humans as a component of the one carbon pool intermediary metabolism pathway. It is formed in the metabolism of endogenous amino acids and is found in the bloodstream of humans and other primates at concentrations of approximately 0.1 millimolar. Formaldehyde does not accumulate in the environment, because it is broken down within a few hours by sunlight or by bacteria present in soil or water. Humans metabolize formaldehyde quickly, so it does not accumulate, converting it to formic acid in the body. There is sufficient evidence of carcinogenicity from studies of humans based on consistent epidemiologic findings on nasopharyngeal cancer, sinonasal cancer, and myeloid leukemia for which chance, bias, and confounding factors can be ruled out with reasonable confidence. Background levels of formaldehyde in food products are very variable and range from values below 1 mg/kg in milk to over 200 mg/kg in some fish species. Considering the wide variability of formaldehyde concentrations in food, daily exposure to formaldehyde would not exceed 100 mg per kilogram of food and per person (EFSA, 2014). (b) Glutathione is a compound containing three amino acids, glutamate, cysteine and glycine. It functions in the body as an antioxidant. It is a vital component in the destruction of free radicals and the detoxification of harmful substances within the body. According to Griffith (Griffith, 1999), the intracellular glutathione concentration in mammalian is app. 1 8 mm. The largest amount of glutathione is found in the liver (5 10 mm), lining of the lungs, kidneys, heart and brain. Glutathione is necessary for the liver to detoxify toxic substances. In humans, the effectiveness of an oral supplementation with glutathione is very controversial also due to the poor absorption by the oral route manly due to the activity of the intestinal enzymes, which degrades glutathione (Schmitt et al., 2015). Oral glutathione did not significantly increase the glutathione level in the blood, as demonstrated in oral glutathione supplementation studies (Schmitt et al., 2015; Witschi, 1992). (c) The C1 metabolism is an essential biological process in organisms responsible for providing onecarbon units for proteins, nucleic acids, methylated compounds, and other biomolecules. It is found in plants, bacteria, fungi, and mammals. Many important biomolecules are synthesized in C1 metabolism such as methionine, formyl-methionine-trna, pantothenate, thymidylate, adenosine, and serine. The C1 metabolism process is also essential for DNA methylation, which controls plant growth and development, with a particular involvement in regulation of gene expression and DNA replication (Vanyushin, 2006). 6 EFSA Supporting publication 2015:EN-885

7 3.3. Evaluation of the study performed and the conclusions made by the authors The EFSA doesn t agree with the methodology used and evidence in the conclusions made by Ayyadurai and Deonikar (2015). The publication is exclusively based on in silico (computer simulation) modelling and not on empirical data derived from laboratory studies. The following arguments were considered not in line with high scientific standards: The authors claimed that online databases including PubMed and Google Scholar were searched in order to identify pathways potentially affected by the genetic modification. Although Ayyadurai and Deonikar (2015) assert that they aggregated data from over six thousand studies, the origin of the data and their validity (peer- or not peer-reviewed publications) is not described and cannot be evaluated by EFSA. The computational model used (CytoSolve Collaboratory ) has not been validated using real data, comprising e.g. natural variability of individual endpoints for a given species. Like all predictive computer modelling studies, the validity of the results depends on the integrity of the input data, the appropriateness of the model and the algorithm used. No such information is given. Therefore, EFSA is not in a position to evaluate the appropriateness of the computational study. As claimed by the authors, a computational study should be the basis for a hypothesis-driven laboratory study, which would serve to support or reject the predictions of the computer simulations. Such empirical study was neither provided nor is it planned to be conducted by the authors. Part of the input of the model is based on scientific publications that investigate differences in protein levels and enzyme activity between a single variety of conventional soybean and a single variety of GM soybean, under a single growing condition. Before using such data as input for a model, it is a prerequisite to establish the reproducibility of the differences in protein levels and enzyme activities in different varieties and growing conditions. The authors find that the genetic modification is a stress factor affecting the whole organism, but such prediction is made based a single pathway (here: C1 metabolism). The interplay of the only pathway considered with the complex network of pathways in the plant and the interaction of such network with the environment are completely ignored. 4. Conclusions EFSA addressed one-by-one the technical issues involved, related to the model chosen, the lack of empirical data, and accumulation of formaldehyde and concomitant depletion of glutathione. Considering that the authors do not provide information on the input data and the algorithm used in the model, that the model is not validated, and that no empirical studies have been presented to support the predictions of the model, EFSA is of the opinion that the author s conclusions are not supported. Therefore, EFSA considers that its previous risk assessment conclusions on EPSPSexpressing herbicide tolerant GM soybean events remain valid. 7 EFSA Supporting publication 2015:EN-885

8 Documentation provided to EFSA 1. Letter, dated 03 August 2015, from the European Commission to the EFSA Executive Director requesting for scientific advice from EFSA on new scientific information in relation to the risk assessment of genetically modified organisms. 2. Acknowledgement letter, dated 11 September 2015, from the EFSA Executive Director to the European Commission. References Ayyadurai, V.A.S. and Deonikar, P Do GMOs accumulate formaldehyde and disrupt molecular systems equilibria? Systems biology may provide answers. Agricultural Sciences, 6, A. Witschi, S. Reddy, B. Stofer, B. H. Lauterburg, The systemic availability of oral glutathione. European Journal of Clinical Pharmacology. Volume 43, Issue 6, pp B.F. Vanyushin, DNA Methylation in Plants. Current Topics in Microbiology and Immunology, 301, B. Schmitt, M. Vicenzi, C. Garrel, F. M. Denis, Effects of N-acetylcysteine, oral glutathione (GSH) and a novel sublingual form of GSH on oxidative stress markers: A comparative crossover study. Redox Biology 6, EC, Regulation (EC) No 1829/2003 of the European Parliament and of the Council of 22 September 2003 on GM food and feed. Official Journal of the European Union, L EFSA (European Food Safety Authority), Guidance Document of the Panel on Genetically Modified Organisms (GMO Panel) for the risk assessment of genetically modified plants and derived food and feed. The EFSA Journal 2006, 99, doi: /j.efsa EFSA (European Food Safety Authority), Opinion of the Scientific Panel on Genetically Modified Organisms (GMO Panel) on application (reference EFSA-GMO-NL ) for the placing on the market of the glyphosate-tolerant genetically modified soybean MON 89788, for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. The EFSA Journal 2008, 758, EFSA Panel on Genetically Modified Organisms (GMO), Scientific Opinion of the Panel on Genetically Modified Organisms on applications (EFSA-GMO-RX ) for the renewal of authorisation for the continued marketing of (1) food containing, consisting of, or produced from genetically modified soybean ; (2) feed containing, consisting of, or produced from soybean ; (3) other products containing or consisting of soybean with the exception of cultivation, all under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2010;8(12):1908, doi: /j.efsa EFSA Panel on Genetically Modified Organisms (GMO), 2011a. Guidance for risk assessment of food and feed from genetically modified plants. EFSA Journal 2011; 9(5): pp. doi: /j.efsa EFSA Panel on Genetically Modified Organisms (GMO), 2011b. Scientific Opinion on application (EFSAGMO-UK ) for the placing on the market of herbicide tolerant genetically modified soybean for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Pioneer. EFSA Journal 2011;9 (7):2310, 40 pp. doi: /j.efsa EFSA Panel on Genetically Modified Organisms (GMO), 2012a. Scientific Opinion on an application (EFSAGMO-NL ) for the placing on the market of the herbicide tolerant genetically modified soybean for cultivation under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2012;10(6):2753, 110 pp. doi: /j.efsa EFSA Panel on Genetically Modified Organisms (GMO), 2012b. Scientific Opinion on application EFSAGMO-NL for the placing on the market of herbicide tolerant genetically modified soybean MON for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2012;10(10):2909, 34 pp. doi: /j.efsa EFSA Supporting publication 2015:EN-885

9 EFSA Panel on Genetically Modified Organisms (GMO), 2012c. Scientific Opinion on application (EFSA- GMO-NL ) for the placing on the market of insect resistant and herbicide tolerant genetically modified soybean MON MON for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. The EFSA Journal 2012;10(2):2560, 34pp. doi: /j.efsa European Food Safety Authority, Endogenous formaldehyde turnover in humans compared with exogenous contribution from food sources. EFSA Journal 2014;12(2):3550, 11 pp. EFSA GMO Panel (EFSA Panel on Genetically Modified Organisms), 2015a. Scientific Opinion on an application (EFSA-GMO-NL ) for the placing on the market of MON MON soybean, genetically modified to contain stearidonic acid and be tolerant to glyphosate for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2015;13(10):4256, 25 pp. doi: /j.efsa EFSA GMO Panel (EFSA Panel on Genetically Modified Organisms), 2015b. Scientific Opinion on an application (EFSA-GMO-BE ) for the placing on the market of herbicide-tolerant genetically modified soybean FG72 for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Bayer CropScience. EFSA Journal 2015;13(7):4167, 29 pp. doi: /j.efsa EFSA GMO Panel (EFSA Panel on Genetically Modified Organisms), 2015c. Scientific Opinion on an application (Reference EFSA-GMO-NL ) for the placing on the market of the herbicidetolerant, increased oleic acid genetically modified soybean MON MON for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2015;13(7):4178, 30 pp. doi: /j.efsa EFSA GMO Panel (EFSA Panel on Genetically Modified Organisms), 2015d. Scientific Opinion on application (EFSA-GMO-NL ) for the placing on the market of the herbicide-tolerant genetically modified soybean MON MON for food and feed uses, import and processing under Regulation (EC) No 1829/2003 from Monsanto. EFSA Journal 2015;13(6):4136, 26 pp. doi: /j.efsa EU, Commission Implementing Regulation (EU) No 503/2013 of 3 April 2013 on applications for authorisation of GM food and feed in accordance with Regulation (EC) No 1829/2003 of the European Parliament and of the Council and amending Commission Regulations (EC) No 641/2004 and (EC) No 1981/2006. Official Journal of the European Union L 157, 8 June 2013, pp 52. O. W. Griffith, Biologic and pharmacologic regulation of mammalian glutathione synthesis. Free Radical Biology & Medicine, 6, pp EFSA Supporting publication 2015:EN-885

10 Abbreviations EFSA EU European Food Safety Authority European Union 10 EFSA Supporting publication 2015:EN-885