Immunology & Immunological Disorders Poster Session
Ethylene diamine tetra-acetic acid (EDTA) is a chelator for metal ions that has found widespread application in modern medicine and pharmacy. It is used for the treatment of heavy-metal poisoning (such as, lead, cadmium, nickel, mercury), as an anticoagulant, and as a non-specific inhibitor of discrete enzymes, such as serum-stimulated lipoprotein lipase (1). It is also often used in analytical chemistry for complexometric titrations and many other purposes. Because the compoundīs toxicity is considered low and acceptable, it is used as a food additive to bind metal ions. The toxicity and limitations of EDTA in some of its clinical applications and animal experiments have been well studied (2,3). The possible cytotoxic effects of this agent, when used with biological human samples to be employed for laboratory studies, need to be carefully considered and adequate measures taken to minimise them. Though the genotoxicity of EDTA was confirmed much earlier in plant and animal cells, it was suggested that it might be harmless against human cells (4). Contrary to this opinion, genotoxic effects of EDTA have been noted on peripheral blood lymphocytes, when used as an anticoagulant, including increased sister-chromatid exchanges, cell-cycle kinetics, and mitotic indices (5).
EDTA is a known detergent with toxic effects on bacterial lipopolysaccharide envelopes and tissue cells. It has been shown to enhance the permeability of bacterial cell envelopes to various toxic chemicals and the enzyme lysozyme (6,7). EDTA also enhances the permeability of the cornea to glycerol (8).
Human breastmilk (HBM) consists of 2-5% lipid fraction, and a suspension of diverse proteins and cellular elements. Breastmilk also contain live cells in the form of macrophages (30-80%), neutrophils (20-60%), and lymphocytes (5-10%), as well as secretory and other epithelial cells, including colostral corpuscles (1-3%) in colostrum. The total leucocyte count in the term colostrum is similar to the level in the blood. This count drops to less than 200,000/ml in the mature milk after 4-6 weeks of lactation and then remains relatively constant throughout the period of lactation (9). Breast-milk is also peculiar in that it possesses structural units of biological cell membrane enclosing milk lipids, which consist mainly of triglycerides. This milk fat globule membrane (MFGM) is derived from the apical region of the mammary gland epithelial cells and is budded off around the milk lipids upon secretion. It is similar to other eukaryotic cell membranes (10).
Few studies have examined the cytotoxic side-effects of EDTA in the course of various laboratory analyses. The toxic effect of EDTA on breast-milk cellular components is hereby described, when EDTA was used as an inhibitor of complement activation in the human breast-milk samples to be employed for in-vitro assays. The evaluation of the mechanisms by which this agent mediates its toxicity might allow for a more sensible laboratory use and clinical application.
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|Ogundele, M.O.; (1998). Cytotoxicity of EDTA Used in Biological Samples: Effect on Some Breast-milk Studies. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/immunology/ogundele0175/index.html|
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