Unidad Ejecutora - UE
capítulos de libros
Some interactions of aluminium with erythroid cells
Some interactions of aluminium with erythroid cells. Review en el libro: Advanced Series in Molecular and Supramolecular Bioinorganic Chemistry - Applications in Medical Sciences.
Nova Science Publishers
Año: 2013; p. 91 - 111
ALUMINUM Aluminum (Al) is a widespread element used extensively in contemporary life, but despite its ubiquity, no essential role has been demonstrated for this metal in biological systems. It is not surprising, then, that this nonessential metal was long considered harmless to humans [Sorenson et al., 1974]. The finding of a link between bone and neurological diseases in patients with renal failure under dialysis treatment and Al toxicity changed this belief. Nowadays, plenty of information suggests that, under certain environmental conditions, Al becomes toxic to plants, animals and humans. Further effort focused on this area will almost certainly improve our understanding of the influence of Al on biological systems. Aluminum sources This element is the most abundant metal occurring naturally in air, soil and water, since it comprises 8% of the Earth?s crust. Human exposure to Al is generally ascribed to the extensive presence of the metal in the environment, enhanced by natural Al mobilization by acid rain [Nayak, 2002], and to its growing industrial applications which are responsible for the spectacular increase in the ?aluminum chemistry? [Atwood and Yearwood, 2000]. Contrary to general thought, environmental and occupational exposures are not the exclusive sources of contact. The widespread use of Al in food, nutritive solutions, cosmetics, pharmaceutical and packaging industries, as well as accidental exposures to the metal, enhance the risk of Al accumulation in human beings. Diet may provide variable amounts of Al, being the mean Al intake by the adult man at least 10 mg/day [Flarend et al., 2001]. For instance, vegetables contain a measurable concentration of the metal due to absorption of highly solubilized Al from acid soils [Matsumoto, 2000]. Moreover, Al is frequently employed as food additive in cheese, baking powders and cake preparations [Nayak, 2002]. Other sources related to diet, such as the Al content in drinks and infusions [Marouani et al., 2007], and that coming from cooking utensils and beverage cans [Ai-Ashmawy, 2011] must be added to the Al amounts found in public water. Most natural waters contain negligible amounts of the metal; nevertheless, the use of Al salts in water purification systems leads to non-insignificant amounts of this metal ion in municipal waters [Crisponi et al., 2012]. The dialysis population was the first known to be at risk of Al overload. Prescription of large doses of oral Al-containing phosphate binders and introduction of Al into the blood-stream due to high-Al in dialysis fluids represented an important cause of Al toxicity in chronic renal patients [Abreo et al., 1989; Wills and Savory, 1989]. Although nowadays dialysis facilities provide high-quality water, abnormally high Al levels are still reported among patients on hemodialysis [Berend et al., 2001; Avila-Díaz et al., 2006; Bohrer et al., 2007; Bohrer et al., 2009; Kan et al., 2010]. Most medications for chronic kidney disease, especially those given 1 intravenously, are the primary source of Al for these patients. The metal uptake is reflected in higher blood Al levels [Bohrer et al., 2009]. For the reasons we have just mentioned, Al toxicity continues to be a problem among patients with chronic disease under dialysis treatment. A further underestimated route for Al uptake is its injection as a vaccine adjuvant, which should be considered regarded as an important contributor to body burden [Crisponi et al., 2012]. Additional sources of Al are cosmetics and antiperspirants [Exley, 1998; Flarend et al., 2001]. However, very few studies have related their use to body Al accumulation. One of the major sources of exposure to Al seemed to be provided by pharmaceutical preparations. Al-containing antacids ingested in high amounts by regular consumers considerably increase the risk of Al exposure and contamination of intravenous fluids, such as albumin or other solutions for parenteral nutrition [Nayak, 2002], which identifies another population at risk of Al overload. Children generally have a higher food intake than adults when expressed on a body weight basis, and therefore represent the group with the highest potential exposure to Al per kg body weight [EFSA, 2008]. Clear links have been established between toxicity in infants and parenteral exposure to Al [Burrell and Exley, 2010] since the metal is usually present as a contaminant in formulas received by preterm neonates [Bohrer et al., 2010; de Oliveira et al., 2010]. The high level of Al uptake avoids the intestinal barrier, and the renal immaturity of newborns impairs its elimination.