CRUCIAL PAPER 4: GM soy reduces metabolic rate, speeds up ageing process
Citation: Manuela Malatesta, Federica Boraldi, Giulia Annovi, Beatrice
Baldelli, Serafina Battistelli, Marco Biggiogera, Daniela Quaglino.
(2008)
A long-term study on female mice fed on a genetically
modified soybean: effects on liver ageing.
Histochem Cell Biol. 2008
Jul 22; : 18648843 (P,S,G,E,B,D)
Abstract
Liver represents a suitable model for monitoring the effects of a diet, due to its key role in controlling the whole metabolism. Although no direct evidence has been reported so far that genetically modified (GM) food may affect health, previous studies on hepatocytes from young female mice fed on GM soybean demonstrated nuclear modifications involving transcription and splicing pathways. In this study, the effects of this diet were studied on liver of old female mice in order to elucidate possible interference with ageing. The morpho-functional characteristics of the liver of 24-month-old mice, fed from weaning on control or GM soybean, were investigated by combining a proteomic approach with ultrastructural, morphometrical and immunoelectron microscopical analyses. Several proteins belonging to hepatocyte metabolism, stress response, calcium signalling and mitochondria were differentially expressed in GM-fed mice, indicating a more marked expression of senescence markers in comparison to controls. Moreover, hepatocytes of GM-fed mice showed mitochondrial and nuclear modifications indicative of reduced metabolic rate. This study demonstrates that GM soybean intake can influence some liver features during ageing and, although the mechanisms remain unknown, underlines the importance to investigate the long-term consequences of GM-diets and the potential synergistic effects with ageing, xenobiotics and/or stress conditions.
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Comment
GM Soy, allergies and other effects (Jeffrey Smith, cited with full
references on Celsias web site)
http://www.celsias.com/article/genetically-modified-foods-unsafe-
evidence-that-li/
GM Soy and Allergies Soy allergies jumped 50% in the U.K. just after GM soy was introduced. If GM soy was the cause, it may be due to several things. The GM protein that makes Roundup Ready Soy resistant to the herbicide does not have a history of safe use in humans and may be an allergen. In fact, sections of its amino acid sequence are identical to known allergens. A portion of the transgene from ingested GM soybeans, along with the promoter that switches it on, transfers into human gut bacteria during ingestion. The fact that the transformed bacteria survives applications of Roundup’s active ingredient, glyphosate, suggests that the transgene continues to produce the Roundup Ready protein. If true, then long after people stop eating GM soy they may be constantly exposed to its potentially allergenic protein, which is being created within their gut. (This protein may be made more allergenic due to misfolding, attached molecular chains, or rearrangement of unstable transgenes, but there is insufficient data to support or rule out these possibilities.)
Studies suggest that the GM transformation process may have increased natural allergens in soybeans. The level of one known allergen, trypsin inhibitor, was 27% higher in raw GM soy varieties. More worrisome, it was as much as sevenfold higher in cooked GM soy compared to cooked non-GM soy. Not only is this higher amount potentially harmful, the finding also suggests that the trypsin inhibitor in GM soy might be more heat stable and, therefore, even more allergenic than the natural variety. It is also possible that changes in GM soy DNA may produce new allergens. Although there has never been an exhaustive analysis of the proteins or natural products in GM soy, unpredicted changes in the DNA were discovered. A mutated section of soy DNA was found near the transgene, which may contribute to some unpredicted effects. Moreover, between this scrambled DNA and the transgene is an extra transgene fragment, not discovered until years after soy was on the market. The RNA produced is completely unexpected. It combines material from all three sections: the full- length transgene, the transgene fragment, and the mutated DNA sequence. This RNA is then further processed into four different variations, which might lead to the production of some unknown allergen.
Another study verified that GM soybeans contain an IgE-binding allergenic protein not found in nonGM soy controls, and that one of eight subjects who showed a skin-prick allergic reaction to GM soy had no reaction to nonGM soy. Although the sample size is small, the implication that certain people react only to GM soy is huge. The increased residue of Roundup herbicide in GM soy might contribute to increased allergies. In fact, the symptoms identified in the U.K. soy allergy study are among those related to glyphosate exposure.
The allergy study identified irritable bowel syndrome, digestion problems, chronic fatigue, headaches, lethargy, and skin complaints including acne and eczema. Symptoms of glyphosate exposure include nausea, headaches, lethargy, skin rashes, and burning or itchy skin. It is also possible that glyphosate’s breakdown product, AMPA, which accumulates in GM soybeans, might contribute to allergies. Finally, mice fed GM soy had reduced levels of pancreatic enzymes. When protein-digesting enzymes are suppressed, proteins may last longer in the gut, allowing more time for an allergic reaction to take place. Any reduction in protein digestion could therefore promote allergic reactions to a wide range of proteins, not just to the GM soy.
Animal feeding studies with Roundup Ready soy indicated toxic livers, altered sperm cells, significant changes in embryo development, and a fivefold increase in infant mortality, among others.
Other references:
Malatesta, M. et al. Ultrastructural analysis of pancreatic acinar cells from mice fed on genetically modified soybean. J. of Anat. 201, no. 5 (Nov 2002): 409.
Malatesta, M. et al. Fine structural analyses of pancreatic acinar cell nuclei from mice fed on GM soybean. Eur. J. Histochem. 47 (2003): 385–388.
Malatesta, M. et al. Ultrastructural morphometrical and immunocytochemical analyses of hepatocyte nuclei from mice fed on genetically modified soybean. Cell Struct. Funct. 27 (2002): 173–180.
Vecchio, L. et al. Ultrastructural analysis of testes from mice fed on genetically modified soybean. Eur. J. of Histochem. 48, no. 4 (Oct– Dec 2004):449–454.
Oliveri et al. Temporary depression of transcription in mouse pre- implantion embryos from mice fed on genetically modified soybean. (48th Symposium of the Society for Histochemistry, Lake Maggiore, Italy, Sept 7–10, 2006).
Ermakova, I. Genetically modified soy leads to the decrease of weight and high mortality of rat pups of the first generation. Preliminary studies. Ecosinform 1 (2006): 4–9.